f\r 46713 TUNE IN TO THE 800-MHz SCANNER BAND! I ^ FEBRUARY 1392 TECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE BUILD THIS SCANNER CONVERTER Gives your scanner unrestricted coverage of the 800-MHz \ band f \ BUILD R-E's HYPER r»i nrif You've never seen a clock project like this before! BUILD A SWEEP/FUNCTION CENERATOR AND FREQUENCY COUNTER Upgrade your test bench today! NEW UFE FOR AM RADIO? New standards for AM might help revive our broadcast band DIGITAL-TO-ANALOG Experimenting with the IBM PC S2.95 U.S. S3.7S CAN FLUKE AMD PHILIPS - THH C}LO[JAL ALLIANCE IN TEST & MEASUREMENT PHILIPS PHILIPS Introducing SCOPEMETEK. There's More Than One Reason to Reach for It. In fact, there's every reason to reach for Scope Meter'' Because only Scope fVleter combines the expertise of Fluke and Philips to bring you a duaf-channel digital scope along with everything youVe come to expect from Fluke digital mutlimeters. The result: an integrated scope-and-muitsmeter that lets you see a waveform and digital meter display at the same time from the same input. Or sv/itch between dedicated high-performance Scope and Meter functions v^ith the touch of a key. That makes it faster and easier than ever to capture^ store and analyze precisely what you're looking for. At a price that looks good, too. To get your hands on a ScopeMeter, contact your Fluke sales office or your nearest Fluke distributor For more product information, call 1'8DQ-44-FLUKE. SCOPEMETER. Now there's only one to reach for* Simply Easy* Built to Take It * Connpleteiy sealed against water diist and contaminants. • EMI protected and measures up to GOO volts rms. • Rugged construction with shock- re si St ant holster • Three-year warrantv from Ruke. Double Duty. * 50 UHi digital storage scope and 3000'count digital multimeter fn one hfildheld package. • Precision Min Max Record and 40 ns Glitch Capture make it easy to troubleshool intermittent failures. • Simultaneous waveform and digital dispEay on a backlit screen you can read across the room. * Intuitive front panel layout for simple, straightforward operation. • Pop-up menus and five function keys for easy control. ' Auto set automatically sets voltage, time and thgger functions, " Safety-designed BNC connectors and probes simplify floating measurements. FLUKE 90 SERIES SCOPEMETER SELECIION GUtDf List Pnce Samp!g RaK True RMS Peqc1& I«t Conhnuity Seeper nme-'OrvtSs^n DiQttaE De-lay m Pre-Tnggef Specfa! MuHimeter Modes OscitiDScgpe Cursois G I lien Capture Wavelflrm Wa^.'etorm Memory Set-Up Memory Malhematics Signal Generator Output Coniponen:! Tester OutpLit_ Optic-a5Ey ^sQli!e[J RS-232-C Jrterface Backlit Display FLUKE 97 SI 795 FLUKE 9S 50 UWi Dual Crianne! FLUKE 93 25 Meig35arnpl££/sficofiid_ AulomatiEalt^ set& VQllaQj. Time arJ Tnggef Pii digits. {>3000 Coufltsj^ AC Pf AC* DC u p to 600V { 1 700V PIc-PkJ Up to ;.8V Yas 1 mV/divtplOOWdrv By WtjiTitieT c( Cyctas. Events. Tjme, flf Zoom Mode Win Max Average Record, Relative i;af!)). dBm. ii8V. dBW, Audio Watrs, % Scale. ffgquency. Srr^oo tiling :^ Change k\itn" 12 Measurements, _Display5 SiHultaneously Averaoe, Vinatjle P&rsistence, Wrn Max Record Store and Recall 8 Wave forms Store and Recall 10 Add. Suhtiaci, MuSiiply. Invert Filter or Integrate Waveforms SinEi!'ivave or Voltage or Current Ramp Full Operation by Remote Coi^rrol Said I Elecuoiui^inescenl 5 mVi'etiv to lOff^/iW ByTima Frequency, Smooihinj* Goes Wherever You Go. • Runs on rechargeable fJiCad Batteries, standard C-cells or the included line voltage adapter/battery charger, • Adjustable tilt- stand comes in bandy as a hanger, too. • Compatible v/ith a wide range of Fl uke m u Iti mele r acces sori es . r CIRCLE 121 ON FREE INFORMATION CARD February 1992 Vol. 63 No. 2 I i 1 j I I 1 J 33 BUILD THE HYPERCLOCK Display the time in eight eye-catching modes! Leon Schmidt 42 SCANNER CONVERTER It allows unrestricted coverage of the 8OO-MH2 band! William Sheets and Rudolf F. Graf 53 SWEEP/FUNCTION GENERATOR Measure square, triangle, and sine waves with this inexpensive benchtop instrument. Michael A. Lashansky 65 EXPERIMENTING WITH ADC FOR YOUR PC Add analog inputs to the PC-based analog-to-digital converter. James J. Barbarello PAGE 33 SCANNER CONVEBTER 48 AM TRIES FOR A COMEBACK Will the new AMAX receivers breathe new life into the AM band? Len Feldman 69 WORKING WITH LED'S Our in-depth survey of LED's continues with practical chaser and bargraph circuits. i Ray Marston I PAGE 42 6 VIDEO NEWS What's new in this fast- changing field. David Lachenbruch 16 EQUIPMENT REPORTS Kelvin 100K DMM kit. 77 HARDWARE HACKER Caller ID update, and more. Don Lancaster 86 AUDIO UPDATE More reader questions. Larry Klein 89 DRAWING BOARD Getting back to our oscilloscope. Robert Grossblatt 92 COMPUTER CONNECTIONS Pen-based computing, Jeff Holtzman 106 Advertising and Sales Offices 106 Advertising Index 12 AskR-E 14 Letters 97 Market Center 27 New Lit 22 New Products 4 What's News I S. 9 m s 1 TO I LJU 6 ElcEtniniES The 800-1000 MHz band of UHF frequencies contains many signals of interst to the shortwave and scan- ner enthusiast. However, many scanner can*t receive those frequen- cies. Our scanner converter re- ceives signals from 800-1000 MHz, and outputs them at 400-500 MHz. That allows you to monitor frequen- cies in the 800-1000 MHz range using your 400-500 MHz scanner You can also use it to measure fre- quencies as high as 1000 MHz with a 500-MHz counter. To find out more about our converter, turn to page 42. COMING NEXT MONTH THE MARCH ISSUE GOES ON SALE FEBRUARY 4. MIDI INTERFACE FOR YOUR PC Your passport to thewortd of computer-controlled music. BUILD DIGI-CALL Keep tabs on phone bills and client billing with this intelligent telephone- line monitor. SCANNER CONVERTER: PART II Easy-to-build down converter gives unrestricted coverage of the 800-IVlHz band. ELECTRONIC TEMPERATURE MEASUREMENT An overview of the components and circuits used to measure temperature electronically. As a service io rcjiders, RADIO'ELECTRONICS pubip^ho^ aVdiiljiblo pl^na or irifoitnotiori rfir&tcrt^ to rt^wsworthy prodiycts, tQcKniqueS and scitsnliflc: and lochnolagical d^velopmci'nts, Qoc^nuso of pcssiblo varinncgs in thu qunlity and conditicjri of ri4]teria!s and workmanship us^d by readars, RADIO ELECTRONIOS di$cl|iirri» ^ny lyrspons^bility for thta s founder Larry Steckler, EHF. CET. ediitor- in -chief and publisher EDnrORIAL DEPARTMENT Brian Fenton, editor Marc Spiwak, associate editor Kim Dunleavy, assistant technical etJitor Teri Scadyto. assistant editor Jeffrey K. HoEtzman computer editor ftob^Pt Gross bf^tti circuite editor Larry Kieln, audio editor Oavid Lachenbruch contributing editor Don Lancaster contributing editor Kathy Terenzi, editorial assistant ART DEPAFtTWIEPiT Andre Duzantt art director Itijae L«e, illustrator Russell C. Truetson^ iflustrator PRODUCTlOrtf DEPARTMEOT Riiby M, Yee, production director Janice So*^ editorial production Karen S. Brown ad verb Sing production Marcella Ainoroso production assistant CmCyLATfOISI DEPARTMENT Jacqueline P^ Chee^eboro Circulation director Wendy Al^nko ci rc u laiion artalys t Theresa Lonibardo circulation assistant MicKele Torrillo, reprint bookstore Typography by Mates Graphics Cover photo by Diversified Photo Services BadiO'Electronics is indebted rn Applied Science & Technohgy Index and Readers Guide to Penodicaf Uter- atore. Microfilm & Microfiche editions are available. Contact circulation depart- ment for details. Advertising Sales Offices listed on page 106- RadlO'Electronics Executive and Administrative Offices Subscriber Custom erServTce: 1-800-283-0652. Order Entry for New Subscribers: 1*800-999-7139. ^> The V^^^ Bureau □I CirculaEion mil A Shocking Offer! Now for the ffrst time in ClE's 56 year history you do not have to be enrolled at CIE to receive our Electronics and Electricity Lesson Modules. Available for a limited time to non-students for the shockingly low introductory price of only S99.50. With CfE's patented AUTO- PROGRAMMED method of learning you1l quickly learn and then master the basics of electronics and electricity and then move on to soldering techniques, applications of Kirchhoff's law, voltage and power, printed circuit boards ... and much, much, more. Your commitment to CIE ends with your payment, but CIE's commitment to your success just begins when you receive your lessons, exams, binder and equipment. This special price includes the benefits CIE normally extends to its students and graduates. Youll receive CIE Bookstore privileges, a pat- ented learning method, access to CIE's student, faculty and alumni electronic bulletin board and a free issue of CIE's school newspaper The Electron". 24-Hour grading and unlimited access to CIBs faculty is avaiiable on an optional basis. And best of all, when you decide to continue your electro- nics education in any of CIE's programs, you'll receive a S100.00 CIE tuition credit certificate. All this knowledge and sup- port will put you on the road to understanding digital electronics, microprocessing principles, computer systems, telecommuni- cations, and much, much, mora. • free issue of "The Electron" • Build your personal burglar a farm • Theory and hands-on training iessons and exams covering '"current and voHage*' through "printed circuit boards'* • CIE BootiStore priviieges • Patent teaming method ' Electronic Bui let in Board privileges All This ForOoly! • 4 $100.00 CIE TUITION CREDIT CERTIFICATE ^ Yes, send me CIE's Introductory Electronic and Electricity Lessons and Equipment. A7302 Name: Street: City: _ Apt #: State: Age: , Zip: Phone .)- BOOKSTORE 1776 East 17th Street Cleveland, Ohio 44114 Total MerchandESB: Ohio Residents add 7% Sales Tax: California Residents add 6 1/2% Sates Tax; Total Ihjs order: 899.50 Shipping and Handfing Charges: Method of Payment: Amount Enclosed: ~i Personal Check or Money Order ~i Master Card ~i visa S5.00 Card Expiration Date: Signature: CHARGE BY PHONE! 9 AM to 4:30 PM Eastern Time; 1-800^321-2155 ext. 7302; In Ohio 1-800-523-9109 ext. 7302 JO SP I m O WHAT'S NEWS A review of the latest happenings in electronics. Device for multiple automobiJe air bags Researchers at Sandia National Laboratories (Albuquerque. NM) have invented a low-energy ex- plosive igniter that could make it easier for automobile manufac- turers to install multiple atr bags In their vehicles. The device, called a semiconductor bridge or SC8, re- quires much tess energy than the hot-wire igniters that are tradi- tionally used in air-bag systems. During the rapid deceleration caused by a crash, air bags are elec- trically ignited by a hot-wire device in an explosive cartridge. As the de- vice heats, the sensitive explosive material burns. A hot gas Es pro- duced that enters the stowed air bag and ignites a gas-generating propellant, which then releases a burst of nitrogen gas that quickly inflates the bag. That entire process takes place in just thousandths of a second. When designing air-bag systems, a worst-case scenario of an almost SANDIA'S SEMICONDUCTOR BRIDGE, which could be used in multiple air-bag systems^ Is shown resting on a penny. The penny^s letter give an indrcation of the device's size. depleted battery is used. In such a case, one hot-wire igniter would consume nearly all of the battery s remaining voltage output — which means trouble for systems incor- porating several air bags and ex- plosively activated seat belts. The semiconductor bridge is about one one-hundredth the vol- ume of a conventional hot wire, and can be heated much faster and with much less energy. Because SCB's are processed on a silicon wafer the chip can incorporate extra ctrcuttry for logic, timing, and safety. Multl mill ion dollar Interactive TV/satellite contract The introduction of nationwide in- teractive television is a step closer with the signing of a multimillion contract between TV Answer, a pi- oneer in real-time wireless Interac- tive Video Data Service CIVDS3 technology, and Hughes Network Systems. Inc. (HNS), manufacturer of interactive Very Small Aperture Terminals CVSAT's), Pending FCC approval the TV Answer system would allow television viewer to use their TV's as communication de- vices to pay bills, order take-out food, shop for groceries, do bank- ing transactions, and respond in real time to game shows, TV shopping shows, advertisements, polls, and interactive news and educational programs. In addition, it would serve as a universal remote control, and would provide on-screen TV sched- ules and VCR programming. The system would work with cable, sat- eilite. and roof-top antenna systems and is expected to cost about $12.95 a month. Similar in structure to a cellular phone network, the TV Answer net- work relies on individual cell sites to provide service to a market area consisting of a maximum of 10,000 households. Each cell site includes a VSAT two-way satellite dish earth- station that communicates with TV TV AMSWER^S INTERACTIVE VIDEO DATA SERVICE would use Hughes Net- work Systems' satellite personal earth statfons to provide direct transmission paths between remote cell sites and the hub station. Answer Headquarters via a Hughes satellite, and a TV Answer radio re- ceiver/transmitter that communi- cates with TV Answer home units. The data received via satellite is transformed at the cell site into a radio signal that is transmitted to each home unit. Viewer responses are relayed to the eel! site and then back to headquarters in the same way. There the responses are pro- cessed and appropriate collection, billing, and ordering activities are performed. The January 10, 1991 FCC Notice of Proposed Rulemaking proposed the allocation of Y2-MHz of the radio spectrum — between 218.00 and 219.00 MHz, which is the frequency on which TV Answer's system oper- ates— for an Interactive Video Data Service. The action is expected to be finalized, and technical stan- dards and licensing procedures is- sued, by mid-t992. Under the initial phase of the con- tract between HNS and TV Answer, HNS will build and install 1000 VSAT units for use in cell sites- enough to meet the projected first- year requirement. The initial phase includes a $2.1 million hub and net- work control system at TV Answer headquarters in Reston, VA, TV An- swer estimates that a minimum of 10.000 VAST units will be needed to provide nationwide coverage for its technology. fl-E Ydu Can Always Spot ihE itcHNiciAN Who Doesn't Use nionoNDi, If you're sending technicians and FSEs into the field witfi equipment otfier than Tel(tronix, ^\ ^^^^^^^■■^ dontlDesuiprised to discover some unusual tools in their seivice kits. Signal flares, for instance. On the other hand, portable test gear from Tek gets technicians to the root of ^'"^^^ the problem long before the problem gets to them. Everything from oscilloscopes and spectrum analyzers to handheld DMMs. As a result, your customers will be back on their feet happy for that. Not to mention a whole lot nicer to in what'll seem like no time at all. They'll be work with. For your employees' sake, get in touch with a Tektronix representative today Or keep an eye peeled for signs of distress, TALK HI nK/1-800-42B-22DD Tektronix Tesl and Measurement CIRCLE T90 OH FftEE tNFORMATION CARD VIDEO NEWS WhaVs new in the fast-changing video industry. DAVm LACKENERUCH • Compact Disc-Interactive. Philips has launched its CD-I inter- active audio-video multimedia sys- tem through 5000 stores, and first reports indicated that the players and discs were selling well Philips changed its mind about brand name, and its first products were issued under the "Philips" instead of the "Magnavox" brand. The list price of the pfayer was dn^pped to $1000 from $1400. but for all prac- tical purposes, pfayers are selling at about $800. and discs fn^m $20 to $40, Using the theme, "the Imag- ination Machine," Philips plans ma- jor advertising campaigns for the system throughout 1992. This is the second multimedia CD system aimed at the general public via at- tachments to TV sets, the first being Commodore s CDTV (which stands for Commodore Dynamic Total Vision). Other manufacturers are competing with video and audio CD-ROM systems designed as computer peripherals. • Zenith moves TV. The last ma- jor American-owned TV manufac- turer Will end color-lV manufacture in the United States sometime this year. Zenith Electronics announced that it will start phasing out final as- sembly of sets in its Springfield, MO plant when its union contract expires on March 22. The company, which has been losing money, ex- plained that price erosion has con- tinued in the TV industry and cost- cutting efforts haven't been suffi- cient, despite wage concessions by its union in Springfield. Zenith will move final assembly of large screen TV sets to its cabinet plant in Juarez, Mexico. Its 19- and 20-inch sets are already being as- sembled in Reynosa, Mexico. Some plastic molding and distribution op- j erations will continue in Springfield. Zenith will continue to operate its large-picture-tube plant and head- I quarters in the Chicago. The only other American-owned TV as- sembler, Curtis Mathis Corpora- I tion, has a final assembly plant in Athens, TX. Although the remainder of TV manufacturers are foreign- owned, many of them continue to assemble their large-screen color TV's in the United States, The lead- ers are Thomson Consumer Elec- tronics (French-owned), which as- sembles RCA and GE sets in Bloomington. IN. and Philips (Dutch), which produces Magna- vox, Sylvania, and Philips sets in Gneeneville, TN. Other final TV as- sembly is done in Huntsville, AL, by Goldstar (Korean): by Japanese manufacturers in Anaheim. CA: JVC in Elmwood ParK NJ: Mit- subishi in Santa Ana. CA and Braselton, GA; Orion in Princeton, IN; Sanyo in Forrest City. AR; Sharp in Memphis: Toshiba in Lebanon, TN; and Sony in San Diego and soon in New Stanton, PA. • "Stereo" TV debate. As it promised more than a year ago (Ra- dio-Electronics March 1991), a company called dbx Technology Li- censing has started a public-reta- tions campaign to inform the public that if a television set doesn't con- form with the FCC-backed stereo- TV system, it shouldn't be called "stereo TV/' However, Thomson Consumer Electronics, manufac- turer of RCA and GE brand sets, has challenged dbx. saying that some of its sets contain a new sys- tem called "XS" and qualify as ster- eo even though they don't use the dbx noise-reduction decoding tech- nology that is officially part of the Multichannel TV System CMTS) stereo standard. Although Thomson's higher- priced sets do use dbx decoding, Thomson says that the XS sound system, which uses phase shift to process the sound, qualifies as ' stereo" even though little separa- tion between left and right channels shows up in tests, dbx demon- strated test results that it says shows that some RCA and GE sets don't reconstruct the true sound transmitted by the TV stations. Thomson retorts that its XS system sounds better than dbx in lower- priced sets. In addition to Thomson, dbx Technology found that some Philips and some Sharp sets don't use dbx decoding in their stereo systems. Both of those companies, which use dbx in some of their sets, say they pian to add dbx across the board to all of their sets later this year. Since there is no official defini- tion of "stereo/' the dispute is ex- pected to continue for some time. Stereo systems using various types of phase-shift techniques to en- hance the "presence" effect in- clude Q sound and SRS, the latter developed by Hughes Aircraft and being used tin some high-end sets by Sony and Thomson as an adjunct to MTS stereo, dbx says that's okay, some people may prefer processed sound, but officially MTS sound in- cludes dbx encoding and decoding; therefore, saying that a set included "broadcast TV stereo" or "MTS stereo" is misleading. • TV for computers. For years we've heard about the upcoming merger of TV and the computer The CD-I system is one aspect of it^ — adding computer functions to the TV set. Moving in the opposite di- rection, IBM and others are adding TV functions to the computer. In March, IBM will offer a TV accesso- ry for its PS/2 computers. That is an adaptor that permits the computer's keyboard to be used to select from among 70 TV channels as well as the other normal TV functions. Of course, other video devices may be input as well, including laserdisc ptayers or VCR's. The TV picture may be viewed full-screen or inser- ted in a window — there's nothing iike watching MTV while working on a spreadsheet! The IBM accessory will carry a list price of $495, which may be cheap for a computer add* on. But in TV-land, the same amount will be a 25-inch color TV set with a remote control. R-E Some Breadboards Cost Less Than PROTO-BOARD brand They Should. PROTO BOARD VI n ^ vi V* I PflOlOftOlt PD 3 , : • *t\'.:: - "CE: ttW. lEE'l V| Vi V) ^ At Global Specialties' we make only one kind of breadboard, the very best, PROTO-BOARD brand. American made and guaranteed for life. Sure, save a few dollars today.. .buy cheap... but remember youonly gel what you pay tor! Is it really worth it??? Askyourself...Dolhey perform like PROTO-BOARD brand? Are they as reliable? Wiil Ihey iast like a PROTO- BOARD brand? How can we guarantee PROTO-BOARD brand breadboard for life unconditionally? Because we control every step right in our New Haven factory, and because we are obsessed with quality. That's why we mold our own plastic and stamp our own precision contacts. We even designed our own machine to assemble each breadboard to exacting stan- dards. Assuring ever/ PROTO-BOARD brand is built to perfection when it leaves our USA factory..,., backed by our unconditional "Life-Time" guarantee. The others, they arrive from Taiwan. With good reason, they are made cheaper! So next time you consider a cheaper breadboard, think twice. You'll need too, because even after you have worn out your second imported breadboard our PROTO- BOARD brand wou!d have still been going strong. PROTO-BOARD brand. The breadboard you only buy once Now which one really cost less? PROTO-BOARD" brand breadboards and the complete Global line of test instruments are in stock at fine electronic distributors everywhere. Can t Wait! Call Toll-Free 1-800-572-1028 ^^^^^ GLOBAL SPECIALTIES nan F iTfi HM paf^P ihiPfYFUiatirihi r Anr> GLOBAL SPECIALTIES' ^ n an 70 Fulton Terraca. Now Hslvan, CT 06512 m * ■ 1 9^3 1 I nterplox E locS ronics mnwrpWX All GlobaE Specif] hies' brondha'irdinc; prcdiK^ls iJndUBtfiQS are made \ti New Ha von Ct. A031 company Learn to troubleshoot and service today's computer systems as you build a 3i86sx/20 MHz mini tower computer! Drain the NRI way — and learn to service today^s computers as you build your own 386sx computer system, now with 1 meg RAM^ 40 meg IDE hard driv€y and exciting new diagnostic hardware and software! Jobs for computer service technicians _ will almost double in the next 10 years according to Department of Labor statistics, making computer service one of the top growth fields in the nation. Now you can cash in on this exciting opportunity — either as a fijdl-time industr>^ technician or in a money-making computer service business of your own — once youVe mastered electronics and computers the NRI way. NRFs practical combination of "reason-why"" theory and hands-on building skills starts you with the funda- mentals of electronics, then guides you through more sophisticated circuitry all the way up to the latest ad- vances in computer technology. Train with and keep a powerful 386sx/20 MHz computer system plus popular Microsoft" Works software! Only NRI gives you hands-on training \vith the finest example of state-of-the-art technology: the powerful new West Coast 386sx/20 MHz mini tower computer. As you assemble this 1 meg RAM, 32-bit CPU computer from the keyboard up, you actually see for yourself how each section of your computer works. You assemble and test your computer's "intelligent" keyboard, install the power supply and L2 meg, high- density floppy disk drive, then interface the high-resolu- tion monitor. Your hands-on training continues as you install a powerful new 40 meg IDE hard disk drive — now included in your course to dramatically increase the data storage capacity of your computer while giving you lightning-quick data access. Plus you now go on to work with today's most popular integrated software package, Microsoft Works, learning to use its word processing, spreadsheet, data- base, and communications utilities for your own personal and professional appHcations. But that's not all. . QuickTech X QuickTecti QuifkTtch (flHtekTecn Only NRI gives you hands-on training with the remarkable RA,C.E,K plug^ in diagnostic card and QuickTech diagnostic software from Ultra-X— prr^feHsional^ sta te'Opthe- art diagnostic tools theit make computer trou blesh ooti ng fast and accu- rate. Your NRI computer training includes all thh^ * NRPs unique Discovery Lab' for circuit dcHign and testing * Hand-held digital multimeter with **talk-you-through^ instructions on audio cassette • Digital logic probe that Ictu you visually examine computer circuits • The new West Coa^t SS$sxl20 MHz computer sy stent, featuring a high-speed 80SS6sx CPU^ 1 meg RAM^ 10 J -key ^^intelligent" keyboard^ 1.2 meg high-density floppy drive J and high-resolution monitor • 40 m4.'g IDE hard drive • MS-DOS, GW'BASIC, and Microsoft Works software • RJi.C,EM. plug-in diagnostic card and QuickT(fch menu- driven diagnostic software • Reference manuals with guidelines and schematics printer ports, serial communications ports, video display memory, floppy drives, and hard disk drives. Only NKI gives you such confidence-building, real-world experience. Only NRI gives you both the knowledge and the professional tools to succeed as today^s in-demand computer service technician. No experience needed NRI builds it in NRI training gives you practical, hands-on experience that makes you uniquely prepared to take advan- tage of today's opportunities in computer service. You learn at your own convenience in your own home. No classronm pressures, no night school, no need to quit your present job until youVe ready to make your move. NRI starts you with the basics, building on that foundation step by step until you have the knowledge and skills you need for success. And all throughout your training youVe got the full support of your personal NRI instructor and the entire NRI technical staff, always ready to answer your questions and help you achieve your training goals, FREE catalog tells more. Send today! Send today for NRI's big, free catalog that describes every aspect of NRl's innovative computer training, as well as hands-on training in other growing high-tech career fields. If the coupon is missing, write to: NRI School of Electronics, McGraw-Hill Continuing Education Center, 4401 Connecticut Avenue, NW, Washington, DC 20008. NOW! Training now includes Ultra-X diagnostic hardware and software for quick, accurate troubleshooting! Now you train with andkeepthe latest in diagnostic hardware and software: the extraordinaiy R.A.C.E.R. plug-in diagnostic card and QuickTech diagnostic software, both from Ultra-X, Using these state-of-the- art tools, you learn to quickly identify and f\/\ . sen^ice virtually an^-^ computer problem on XT, AT 80286/80386, and compatible i ^ /X I J machines. ^A^M^H^H You discover how ^ to use the R.A.C.E.R :■ ■ diagnostic card to identify individual defective RAM chips, locate interfacing problems, and pinpoint defective support chips. Plus you learn to use your QuickTech diagnostic software to test the system RAM and such peripheral adapters as parallel IBM IS a reKistered Irademark oriiilerriatieTial Busincs« Machines Corp. R.A CE R. iintl QutckTcch are negislered tradtm^irks ofUllrii-X. h\c. SEND TODAY FOR FREE CATALOG McGnaw-Hill Continuing Education Center 4401 Connecticut Avenue, NW S'^Si Schools Washington, DC 20008 jjjll > 386SX I /check one FREE catalog only I MICIIOCOMPU TER SERVICING I TVWideu/Audio Servicing n Telecommunications □ IndusLriiil Electronics n Security Electronics □ Electronic Music Technology ~~l Basic Electronics n Automotive Servicing For cfirenjr courses approved under Gt Hill l_l check for detxiii». n Computer Protfr am mi □ PC Software Lnf^i ottering Using C □ Desktop Publish inji □ Word Processing Home Business □ Paralegal □ Building Construction □ Bookkeeping & Accounting Name (please print) I City/State/Zip Accredited Member, National Home study Council 3 022 | ASK R E Write to Ask R-E, RadiO'Electronics, 500-B Bi-County Blvd, Farmingdale, NY 11735 MOTOR SPEED CONTROLLER I have a electric model boat and rd like to be able to control the speed of the motor. The cir- cuit should be able to make the motor go from very slow to very fast without stalling. Tve tried all sorts of things but haven*t had any luck— particularly at low speed. The motor is powered by a 7.2 -volt battery pack. Do you have any circuits that can help me?— A. Balsys, Howell, NJ Electric boats aren't my thing but I would have imagined that they all had some way to vary the speed of the motors. Oh well, you live and learn. Controlling the speed of a small DC motor is something IVe talked about several times before but^ judging from the number of times I get asked about it in letters and on the phone, it seems a lot of people are interested in the subject. There ane several ways to get the job done and even some fairly inexpensive commercial products that will do it for you. In this case, particularly with such a low-voltage motor, there s an easy circuit you can buifd that will do the job and operate reliably for the life of the motor The circuit Tm referring to Is shown in Fig, 1 . Despite its apparent simplicity, the circuit will drive the motor over a range of speeds from dead slow to full ahead (that's boat talk, I think), without any stalling at even the lowest speeds. The reason it can do this is that the circuit works ^ by controlling the duty cycle of the g motor rather than, as in other con- ^ tnollers, the supply voltage. I Two of the inverters in the 4049 ■g ane set up as an oscillator whose . frequency is roughly determined by: I F - 1/14RC 1 where R is the total value of the % potentiometer The two diodes iso- ^ late both the positive end negative halves of the output frequency and ^ make the output waveform stick close to a 50-50 duty cycle all 12 through its entire operating range. The remaining inverters in the package are all ganged together in parallel to increase the output drive to the transistor While you can use just about any inverter for the cir- cuit, the 4049 is probably the best choice since it can handle more out- put current than other inverting gate chips. Just make sure you pay at- tention to the fact that the power pin on the 4049 is pin #1— a departure from the other IC's. RG. 1— THIS CIRCUIT WILL DRIVE a small DC motor over a wide range of speeds without stalling by control litig the duty cycle of the motor rather than the supply voltage. Even though the schematic shows the supply voltage to the motor and the circuit on two sepa- rate lines, there's no reason why you can "t use the 7.2-volt battery for both of them. The battery is supply- ing a perfect voltage for CMOS stuff like the 4049. There's nothing critical about the fayout of the circuit and you can build it using any technique you want. In actual fact, it s such a handy circuit you may want to generate a printed circuit board for it so you can easily use the circuil somewhere else WATCH THE SPEED LIMIT I have an XT-corn pat ibte com- puter and, while it works per* feclly, it's turning out to be much too slow for some of the newer software I want to use. Is it pos- sible to speed up the computer by just changing the 14*1318- MHz crystal and are there limits as to how much of a speed in- crease this will give me? — R Geeben, Hunter, IN Before we get into this, f want to make sure you understand that any increase in speed you can get like this is going to be far outweighed by the amount of brain damage it takes to do it. The theory is great but the maximum speed of a motherboard, like an automotive engine, is a con- sequence of how it s designed. They both have red- fine numbers. At the most basic level, the parts on your motherboard were chosen to match the computer s original de- sign specifications. The memory, I/O controller, interrupt controller, and DMA (Direct Memory Access) con- troller have maximum speed ratings and the ones in your computer were ptc .ed to match the speed of the board. The faster any chips speed rating, the more expensive it is. I don't know who made your mother- board but it's a safe bet that the parts on it are only as fast as they have to be. Changing the crystal changes the board s master clock and the more you step on the electronic acceler- ator, the closer you're going to get to the point where these chips first get flaky and finally fail completely The point where that happens is de- termined by the speed rating stamped on the chips and the de* tails of the design of your mother- board. Memory chips have a maximum speed rating as well and it s usually stamped on the top of the IC right after the chip number A suffix of 20 means 200 nanoseconds. 15 means 150 nanosecondSn and so on. If the only crystal on your moth- erboard is a 14.31818-MHz one, it's more than likely that your computer is running, like the original IBM PC. at a speed of 4.77 MHz. This means that your motherboard can operate with mennory as slow as 200 nano- seconds. If that's what you have in your machine, you don't have much of 3 chance of upping the system speed and still maintain much in the way of reliability Its possible you can overcome these problems if the design of your motherboard incorporates enough wait states to do things like memory refresh and other housekeeping chores at an increased speed. But there's still another problem that has to be considered. There are two clock frequencies at the expansion slots and most of the cards you plug into the mother- board are designed to expect the two clocks to be in a particular fre- quency range. Pin #B20 is known as the CLK and on your motherboard it's probably a buffered version of the 8088s clock frequency — 4.77 MHz, That frequency can be higher and you'lf frequently find that it s as high up as 8 MHz. The second frequency is the one that can cause you a problem. In the original PC Cof which yours is a clone), pin #B30 was a buffered ver- sion of the crystal frequency — 14.31818 MHz. That has remained a standard, even up to this day Mea- sure the frequency at that pin on the latest 33-MHz 486 motherboard and you'll find 14.31818 MHz. When you change the crystal on the board, you'll also be changing both frequencies at the expansion slots which can cause a problem with some cards that use the two clocks. The biggest problem will come with floppy-disk controllers since they use those clocks for writing to the disk. Even if you somehow avoid the problem, it's a guaranteed fact that you'll have problems formatting disks. Keeping all this stuff in mind, you can start experimenting with higher- frequency crystals to see how far you can go before you have major problems. My guess is that the most you II be able to get is a 50% increase in speed. If you want to be able to format disks, you have to supply the computer with the origi- nal frequencies so don't get rid of the original crystal Probably the easiest way to do that is to have both the crystals on the mother- board and use a switch to select one or the other We're talking about doing a good deal of work here and the possible rewards are really minimal. A 50% increase in speed may sound like a lot but youMI find that the practical effects are just not all that notice- able. A much better solution to the whole problem is to buy a new motherboard that's been designed fnam the ground up to run faster than the one you have now. R-E "Plant a tree today for all the world to share'' You can make life l>ctter for your children and for the future, loin mc and plant a tree today for all the world to share. For your free lmKhure» write: Trc es for A me ri c a , T he N a t i on a 1 Arbor Day Fouirdatuin. Nebraska City, NE 68410. John Denver for 'Hit* N^itknial ^ Uarn at home In ^pare time. - No prevbu s peri ence n e^ed ed I No costly school. No commutini; to c^la^s. The Original Home- Study course prepares you for the "FCC Commercial Radio- te I cph one L i cense,' 'This valuab 1 e license i s your professional ''ticket*' to thousands of exciting jobs in Communications, Radio- TV, Micro wavCf Maritime, Radar^ Avionics and more.,, even start your own bus mess I You don*t need a college degree to qualify, but you do need an FCC License, No Need to Quit Your Job or Go To School This proven course is easy^ fast and low cost! GUARANTEED PASS— You get your FCC License or money refunded. 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IcM a 1 4inu iinli'} i liMniiif^ iuEiyiHi i an iMniSlii.f'KUiir li'v^ (lian tsl [ .111 M,ir m n f -r S I 'HHiiS Fits INFORMATION PACKAGE cafi Of Write: Toil-Free 1-800-537-0589 Viejo Publications, Inc. 4470-107 Sunsel Blvd. #600 ^ Los Angeies, CA 9(M)27, DepL REG CIRCLE m OH FREE tNFORHATION CARD I m h3 LETTERS Write to Letters, Radio-Electronics, 500-8 Bi-County Blvd., Farmingdale, NY 11735 VEHICLE GENERATORS AND REGULATORS Radio-Electronics and its predecessor, Radio-Craft, have given me much pleasure for 50 years. Robert Grossblatts articles have been favorites, but he fell off the track with his commenL "... (ve^ hide) generators and the regulators that control the current they pro- duce are a really stupid charging system (Drawmg Board. Ra- dio-Electronics. December 1991), Low-cost, high-current silicon rectifiers that made the superior al* ternator available were not de- veloped until after the transistor was invented in 1947. There hap^ pened to be a lot of high technology befons that, Radio. TV. computers, and automobiles ad pre-date the benefits brought by advanced solid- state devices. As I recall, sub- marines, Rolls Royce automobiles, and high-speed aircraft all used gen- erBtorSp and the electnomechanical voltage regulators th^ rBquired. I don't believe the word "stupid" characterizes that use. I suspect the author was just try- ^ ing to interject some lightness— which is all right with me — but his description of the operation of the older voltage regulator is incorrect. The generator s field current was modulated by a voltage-sensing re- lay that inserted varrous values of resistance in the field circuit, not the output lead. The varying field cur- ^ rent would then cause the output g voltage to remain at the desired val- ^ ue. The relay was also designed to § sense the ambient temperatufB and change the generator-charging volt- \ age accordingly. The voltage reg- .| ulator case usually contained a S current-limiting relay to protect the 1 generator fnDm overload, and a re- ^ verse-current relay to prevent the battery from discharging through ^ the generator windings when the engine was not running. 14 These latter two functions were not needed in the alternator, but when they were first installed in new cars, there were no low-cost, high- current transistors developed that could operate at the high-tempera- tunes tn the engine compartment. So the same old electromechanical voltage regulator that had been used for 40 years was used again with the new alternator! The rest of Mr, Grossblatt s arti- cle was well done and informative, as usual. I just didn't want to read your fine magazine for the next 50 years without contributing to its technical exceltencel GEORGE W. HAILS Arlington Heights, tL TESLA COIL IMPOSTORS I have been tennpted several times in the past to write to vanous magazines after the appearance of certain articles on the construction of Tesia coils. Don Lancaster s com- ments on the TesIa coil WardwarB Hacker. Radlo-Electronics. Oc- tober 1991) finally pushed me to fire up the word processon I agree that many "TesIa" coils are essentially nothing more than glorified step-up transformers. The TesIa coil, however, is meanUo gen- erate its high-frequency high volt- age by taking advantage of the special properties of the resonant Cq uarter wavete n g th > t ra ns m i s sion line (also known, somewhat eso* tericatly. as the Ferranti effect). It can be shown that the voltage amplitude V. at the unloaded end of an ideal (i.e.. lossless, uniform, etc.) quarter wavelength transmission line driven by a source of resonant voltage of amplitude Vg. and of im- pedance Z3 at the resonant fre^ quency (assumed mal for notational simplicity) is V = tZo/Zg)V5. where Zq is the characteristic impedance of the line. This is different in numer- ous ways from the standard voltage multiplication of a transformer as it should be; these are quite distinct physical phenomena. Although the physics of the trans- former is pretty amazing, what is more impressive is that a wire Cor more properly, a transmission line) may itself act as a "transformer/* A great experiment that shows this is the construction of a mock trans- mission line using discrete compo- nents to model (mock) the distributed parameters of a real transmission line. In reality, a TesIa coil impostor is pretty easy to spot, It will suffer from a variety of maladies, some of which include impnDper magnetic coupling (making it a transformer instead of a propagating transmission tine) and a marked insensitivity to resonant fre- quency tuning. Generally, even the most heinously constructed "Tesla coils'" will generate hefty attention- grabbing sparks, but they are often missing the "magic and mystery" of the physics of the resonant line that makes it a tme Testa coil. MATTHEW KLEJWA Schaumburg. IL HERE'S TO HOW-TO ARTICLES I'm writing in response to Alex Funk's letter (Radio-Elec* tronics. April 1991J titled "Mac- Hack Attack/' It might be true that ff you add up all the components re- quired for a home-buitt computer system, the final price tag will come close to a dealer- bought system. However, there are quite a few peo- ple in this world who cannot afford to shell out over StOOO at one time, but who can afford to do it piece by piece, [fs a lot easier to spend $25 or $50 at a time than it is to spend $1000. And how can you put a price on your time when you are learning how to build something as useful as a computer system? How much is your time worth when you sit and watch television? Please keep publishing those how-to articles! JOHN CULLIVAN Nties, OH The world is at your fingertips witli... The Grundig Wirld Band Receiver AniiDuncing a revolution an^ brcak- thraugh in world-band radios... from Gnmdig, the leader in German short- wave electronics. This miracle of miniamrization is not ssold in U.S. stores or catalogs— only VVillabec & Ward has it! Tbne in to events around the globe* The RK-709 is the worlds smallest 12^ band receiver —AM, FM, FM sStcrco (with headphones, included), und ail 9 major shortwave bands. Small enough to fit imo a pocket, briefcase, or purse, yet big on feauires. Telescoping antenna pulls signals from aiiy^^'here in the world. Listen to legendary BBC newscasts— the best in the world. Hear what Radio Moscow is saying about Gorbachev; Yeltsin, and President Bush, Listen to the Voice of America when you travel abroad. Follow a crisis or breaking story wherever you are and no matter \vhere it's happening: Baghdad, Patiaiiia, Beijing or Tokyo, You don't have to pack a travel alarm, eitiier. \bu won't need it— this is betten The RK-709 wakes you \viEh the radio or its ingenious "Humane Wake System'" —the tone begins softly and gathers volume until you w^ake up! The digital alarm clock Icatures a sleep timer that turns off the radio 10 to 60 minutes after you rum in! Only $159! Payable in monthly installments. The Grundig RK709 is only SiS9 (plus S7.50 shipping/handling), payable in convenient monthly credit card installments* Includes deluxe carrying pouch and stereo headphones. One year warranu', 30 day money back guarantee. Order today. W'ill^bctr & Ward 47 Rich,irtl* Avenue Ntini ilk, Com^ 06857 CALL TOLL-FREE: 1-800^367-4534 Ext. 623-165 -GrtJirdig RK'709 Pkasc scEid me . World Rand Rcct;ivor(s)- I^oreach receiver, charge 4 instLiilmciits of S4T63* to my credit card: □ MasterCard DVISA □ Discover □Am. Ex. Credit Card # j Name ' Addrc{ng/ CALLTOIl^FREE: 1-800-367-4534 Ext. 623-165 EQUIPMENT REPORTS The Kelvin lOOK Digital Multimeter c B a: 16 Mosf multimeters are ready to use right out oftfie box- but not tlie Kelvin 100K CmCLE to ON FmE INFOHMATION CARD ■ f we were to tell you that this I review is about an inexpensive I muitimeter, you'd probably be in- cltned to turn to the next page. After all multimeters are as common to- day as silicon chips, and the fea- tures found on inexpensive ones have been around for years. So what can we tell you about the K&lvin fOOK digital multimeter that you couldn't already guess? The an- swer is that it's available as a kit. The Kelvin t OOK (Ke\vm Elec- tronics, 7 Fairchild Ave., Plainview, NY 11803) comes with a PC board and all parts that mount on it, a case with a hackstand (that's always handy), a pair of test leads, an owners manual an assembly man- ual, an extra fuse, and even a 9- volt battery, ell for $29.95. The tOOKs features include a 3'/2'digit LCD: DC ranges of 2, 20. 200. and 1000 volts: AC ranges of 200 and 500 volts: resistance ranges of 200 ohms. 2K. 20K, 200K, and 2 megohms; and DC current ranges of 2 nf^, 20 mA. 200 mA. and 10 amps. There s no pn3vision for mea- sunng AC current. The tOOK also hosts a diode test* a low-battery indicator, and a battery test — a handy feature for a general- purpose multimeter In the "battery test" mode, the meter will display the voltage of any 1.5-volt battery under a 100-mA load or the voltage of any 9'Volt battery under a 6 mA load. It's likety that not too many experi- enced kit builders will be interested in building the 100K. mainly because they almost certainly already own a multimeter However, the fOOK kit is perfect for any beginner in elec- tronics or a child who s old enough to attempt soldenng — especially a kid who's always playing with his dad s multimeter! The assembly manual is par- ticularly welt-suited for a classroom environment, as it reads like an elec- tronics lab manual: parts are in- stalled a small group at a time, alternating with precautionary cir- cuit checks, explanations of how each section of the circuit works, troubleshooting tips, and various quizzes on what has been covered so far Experienced kit builders may ac- tually find the assembly manual somewhat irritating, because the sections in which components ane installed are scattered throughout a lot of other explanatory paperv/ork. Remember though, that the kit is aimed at beginners. But this is where the kits one flaw emerges: the assembly manual contains more than just a few typographical emors, A seasoned kit builder should be able to overcome these problems but they may be very confusing to the beginner Let s go over the as- sembly manual and point out any problems we encountered. The manual starts out with an in- troduction to the meter and a table listing all of its specifications. A schematic of the meter's circuitry and a parts list follows. Diagrams of all of the parts are pruvrded to help you quickly identify everything, A parts-placement diagram is next, al- though the PC board is silkscreened with all of the compo- nent designations as well Also in- cluded are charts to help you identify resistor values by their color codes and capacitor values by their numbering. Pinout diagrams are provided, of the 3y2^digit LCD. the 7106 A/D converter, and the quad xoR gate used in the meter. There's a brief discussion on proper soldering techniques and the proper handling of IC s. A list of all tools needed to build the meter is also given. Circuit theory is the last thing to be covered before the actual assembly of the board begins. In the first assembly procedure, certain resistors and capacitors must be soldered to the PC board, and some might find this step con- fusing. You ane instructed to install C14. 10 nR and C16. 0.01 piF— but the two capacitors are actually the same value. And the fact that the parts list shows capacitors C14 and CI 6 to be "0.0 \lF'' only adds to the confusion. Next you have to install the 40-pin 7106 IC so that the A/D circuitry can be tested out. which also re* quires the temporary installation of the battery clip the LCD. and the riotary knob. The LCD and knob re- quire a bit of sub-assembling before attaching them to the meter, and for some reason the sub-assembly in- structions are found much farther on in the manual. The assembly di- agram shows the back of the rotary knob as having six plastic tabs over v^ich you arB to snap on six metal contact clips — but the knob that came with our kit had seven tabs. 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The instrument of- fers basic 24-hour DC ac- curacy of 0,0015 percent, and the best AC accuracy and widest AC bandwidth in its class, according to Hewlett-Rackard, Designed for system and bench applications, the HP3440tA can be incorpo- rated into existing systems with no changes in soft- ware, and includes such system DMM features as dB. null, diode lest, and continuity. HP*IB and RS-232C interfaces are standard. In addition, it pro- vides limit test, minimum/ CfRCU Ifc ON FREE INFORMATION CARD maximum testing results, storage of 512 readings, automatic-reading hold, auto-ranging, display up- dating, and almost in- stantaneous continuity readings. The easy'to-use front panel was designed in re- sponse to extensive user testing, and a menu feature allows the user to easily modify secondary func- tions. An optional strap-on pouch can carry the power cord, interface cables, test probes, user and service manuals^ and other ac- cessories. The carrying handle and bumpers can be removed for rack in- stallation. The HP 3440 J A digital multimeter has a U.S. list price of $995 — Hewlett- Packard Company. Love- land Instrument Division, P.O. Box 301. Loveland. CO 80539: Phone: 1-800-638-8787. CABLE/TV SIGNAL LEVEL METER* Designed for mea- suring performance levels during system con- struction. installation, and maintenance, Leader In- struments' Model 95t CATV signal-level meter can be used by the broad- cast-TV, FM, MATV, and CATV industries. It has an auto-scanning feature that selects 32 channels en- countered and displays measurement results that ane auto-ranged and auto- scaled for storage to Cor re* call from) four groups of eight channeUbargraph data registers. Users can also select and store four memory-scans of picture and/or sound carriers, and measured results. 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Developed to help engineers, techni- cians, and hobbyists de- sign and draw electronic circuits on-screen , AutoSkem CAD Version L4 produces a high-quality printout, eliminating the rough hand-drawn sketch, 9 • ? r □ 7 ^ O < c ^ " ■ * ■ " 1> < t> T> < < m m m m m ^ SYMBOLS CIRCLE 18 ON FREE rNFORMATION CARD Drawings can be con- structed using lines, text, and symbols. A software li- brary of more than 50 pre- defined electronic sym- bols, logic gates, op-amps, transistors, diodes, coils, etc.. is included. Users can cneate their own symbols and organize them into an unlimited number of librar- ies of up to 100 symbols each. Text can be nictated and scaled to five sizes be- fore being placed m a draw- ing. Version 1.4 features improved graphics and drawing features for EGA and VGA systems: "rub- ber-banding" for drawing 48HOUR ELENCO & HITACHI PRODUCTS SHIPPING y^j DISCOUNT PRICES 1-800-292-7711 Hitachi RSO Series (Portable Real-linne Digilal Slortige Oscrlbsc^op^^) VC'6023 - 20US/B _ VC'6024 '50MH2. 20MS/5 VC'6025 - 50MH2, 20MS/S VC'6a45 ■ lOOMHs, 40MSAS _ VC-6145 ■ IOOMH1. tOOMS/S SI ,695 SI, 995 S2,195 S2,995 S4,496 RSO's iTom Hitachi EeaSiiro roll mode, averaging, &av$ memory, smoothing, iniefpolciiliDn, prerngg^nrtg, cuf^ar measurements. These scopes ertab)e more accurate, simpNer observaiion of complex wavetorms, in addittpn to such iu notions as hardcopy via a plotter interface and waveform transfer via (he interface. Enjoy the comfon of analog cind the power (o digiEaL SPECIAL BUY V-212 - 20MHz Scope $425 25MHz Elenco Oscilloscope ^222 $349 S-1325 • Dual Trace * 1mV Sensitivity • 6" CRT * X-Y Operation • TV Sync • (2) Ix, lOx Probes included Hitachi Portable Scopes DC to SOMHz. 2-Chanm\, DC offset tunc- troo, Altemote magnifier funclion V-525 - CRT Readout. Cursor Meas. S995 V-S23 - Delayed Sweep S975 V-522 - Basic Model S875 V'422 ' 40fvlH2 S775 V-223 - 20mz delayed sweep $695 20MH^ deluxe ^ $525 PRICE BREAKTHRU 20 MHz Digital Storage Oscilloscope • Ans^og/D\gii3l Scope • 2K word per cnannel merwry DS2D3 • 1 0MSs sampEinp ra^e $795 i Stale-cl-art lechnDiofly • IndLrdes prot>es HITACHI COMPACT SERIES SCOPES Th^s senes provkJes many new for^Csons su;ch as CRl ReBdcu-:, Cursor measurements {V-iOS5-'i 065A,'665A), Fre- GueiXy Ctr. [VAO&S). Sweneplime ALlorangtng. Deiayed sweep afwl Tripper LocK ustng & 6-inCti CRT. You don't fee! tne compacin^ i^n terms of pfiffoEmance and opemtion. V'650 - 60MHz, Dual Trace $l.i49 V'66SA ' 60MHz. DT. w/GUrsor SI .345 V 1060 - 100MH2. Duai Trace $1,395 V-1065A - lOOMHs. DT, w^cufsor , S1 ,649 V-1085 ' 100MH2, QT. w/cursor $1,995 V-1 1 00 A - 1 0OMHz, Quad Trace S2 J 95 V-1150 - 150MHz, Quad Trace 52,635 Elenco 40MHz Dual Trace Goocilo J495 ^^^"^ S-134Q I^High luminance 6" CRT • ImV Sensitivity ' • lOKV Accel eralion VoCiage # { "jW , 17ns Rise Time " ^^i' * X-Y Operation ' Includes (2) lx, lOx Probes AJI scopes inctLKje probes. scherrtaticsH operators m annual arid 3 ye^ (2 yrs for Etenco s^cpes) world wide warranty on parts & labor. Many aooe^sor^es available for all Hitachi scopes Call or write tor complete sp^iticaiions on these and marry other f jne oscilloscopes. 1 x, lOx Scope Probes: P- 1 65 MHz $ 1 9.95, P'2 1 OOMHl $26.95 B + K TEST EQUIPMENT All Models Available Call for special price Digital Capacitance Meter CM'ISSOB am^ $58,95 91 i ' I 9 Ranged iBJ I .1pf-20,DaDuld |HMj .5% b^sic accy. I j Zero control Case DIgttol LCR Meter LC-1B01 S125 Coils 1uH-200H Caps Ipl^^OOuf Res .01'20M Big 1' Display Muttimeter wttti Capacitance & Transistor Tester $55 CM-1500B Reads Votts^ Ohms CurreM, Capadiors, Transistors and DEodes. / with taso FLUKE MULTIMETERS Alt Modeli Avoiiobie Fluke 70-11 $65 Fluke 77-11 $145 Fluke 79*11. S169 Fluke 87^ S289 Coll tor spec 1 01 price Quod Power Supply XP-580 .$59.95 2- 20V @ 2A 12V @ 1A 5V@ 3A '5V @ .5A Futly regulated and short circuit protected Triple Power Supply XP-620 Assembled $6? Kit $45 210 15V@ 1A. (or 4 to 30V @ lA) and 5V @ 3A All the desired leatures for doin-g experimefiEs. Feature'; $hon circuit prccecti'on, all supplies AM/FM Transistor Radio Kit with Training Course Model AM'FMIOS $26-95 Makes a graat schod prcject Trtie RhlS41/2 Digit Myltfmeter M-700D $135 .05% X Accuracy .1% R*si$lance m\\h Freq. Courtier aid Dq^.\jx6 Ca$e GF-6016 Function Generator wl1h Freq. Counter $249 Siri>e, Squar^s, Triangle Pulse. Ramp, .2 to 2MHz Frflq Counter .1 - lOMNz Int/Ext opardton GF-8015 wtthoui Freq. Meter $179 Function Generator #9600 $28.95 Provides sane, triangle, square wave from t Hz lo 1 MHi AM or FU Ciip ability Learn to Build and Program Computers wltti this Kit Inctudes: All Parts, Assembly and Lessen Manual Model MM*800D Wide Bond Signal Generators $129.00 Sartingtrorn scratch you tiuW a complete system Our !^cn} M^ter trainer leach« you to wrrte into FiAMs, flOMa artd run a 6005 friicroprooos*Qr, which uses similar nnachijie lanuu^ge as IBM PC, SG<9000 $129 Rf Ffflq KOK^SOMHi AM Modula^ tion oi IKHi Variable RF oulpLsl SG-9S00 w/ Digital Display & 15a MHz bullt4n Counter S249 XK-500 Digital / Analog Trainer A complete minl lab jor buMng, testing] prototyping analog and digital dreuita Elonco's Dkgllal f Analog Tramer isspecisljy desjgfied Ior^i:hoo1 proj&cEs, wilh S buiLl in powe; supplies, jnclijdes a lurjciJon genetator with continously v^tiMa, slrve, irlaagulat, squao wave formSr Alt power supplies are regulaled an-d prol^cied against stioris. Power Suppllos ■ Variable Power Si>pply • »i25tE}20VDC@.5Amp (*1 S&lo 1SVDC@ 1 Amp) - t .SS to EOVDC @ .5 Amp (1.2510 -t5VDC@ 1 Amp) • +12VDC@ 1 Arnp . .)2VDC0 \ Amp t kSVDG @ V Amp - 30 VAC Cemer lapped @ 15VAC (g> T Amp Ana tog » Sccllon k Funcdon Goneralor Sin a, Triangular, Square w^vg lorms • Frequsf^cy adjustable In live ranges from 1 to lOOKHi • Fina Iruquency aajjusl • Amplitude adjjusl • DCoM^ei • Modulalion FM AM DIgUal - SocUon • Eigbt data swichfis > Two no bounca logic swrtches • Eiight LED roadauEs TTL bulJeiad • ClocXf^equenc/ t lo JOOKHz • Clock ampljiude 5VPP square wave Bratdboards • Z bJ'Madtgard^, oach contain: 040 tia polms (totaJ 1;680} 23 15 Day Money Back Guarantee 2 Year Warranty prjce^subjecMocnar^ge WRiTE FOR FREE CATALOG CIRCLE 100 ON FREE IMFORMATION CARD straight or diagonal lines; the ability to save the draw- ing configuration file witfi all current program drawing configurations: improved mouse support: and inter- nal high-resolution printer drivers for 9- and 24-pin dot matrix and HP LaserJet printers, and HP Pen Rot- ters. Parallel as well as se- rial interfaces are sup- ported. The program re- quires an IBM PC, XT. AT PS/2, or compatible com- puter running DOS 2.1 or higher: 384K RAM; and CGA. EGA. VGA. or Her- cules graphics. AutoSkem CAD Version 1.4 costs $49.— BSOFT Software, Inc,. 444 Colton Road. Columbus. OH 43207: Phone; 1-800-728 3805. CARTOON-A-DAY PRO- GRAM. A PC calendar pro- CIRCLE 19 ON FREE iNFORSiATiON CARD gram with a tv/ist* the Cartoon-A-Day Calendar Pius from Individual Soft- ware offers DOS and Win- dows users a daily dose of whimsical humor in the form of the farcical drawing of nationally syndicated "Inside Out'" cartoonist Kevin Pope. The daily car- toon can be added to per- sonal calendars* printed correspondence, daily to- do lists* or schedules. The program displays (and prints) personal schedule information by the day. week, month, or year, and even keeps track of vaca- tion time, personal plans, travel time, and holidays. It can also be used to create or update to-do lists. Both versions feature digital and analog clocks: the Win- dows version also features time saving "Quick Memo" and "Quick Fax" functions that generate a memo or fax cover sheet that incorporates the daily connputer right from their computer The DOS ver- sion runs on any IBM-com- patible PC with DOS 3.3 or higher and 51 2K of memo- ry. The Windows version requires Windows 3.0 soft- ware. The Cartoon-A-Day Cal- endar Plus program (for DOS or Windows) costs $29.95,— Individual Sofl- ware. 5870 Stonendge Drive, #t, Pleasonton. OA 94588; Phone: 1-800'822-3522- ROBOTIC PROBE. Aimed at the electronic service in- dustry, where low volume boards, varying device technologies, and a wide range of repair problems exist, the Prober RP388 is a computer-controlled, electro-mechanical probe that automates the testing process for components of various sizes and packag- ing, including surface* CIRCLE 20 ON FREE INFORMATION CARD for Success. Work Smarter for Less ith a B-t-K PRECISION S I I Ui er Portabtfi IC Color Pattern Gdtieralor ■ Battery operated , compact portabte unit ■ 13 patterns incluciing gated rainbow ■ CH 3/CH 4 output crystal controlled ■ Composite video output to 1 Vp-p ■ Progressive scan Model t21lC $229 NTSC Signal Generator ■ NTSC color bars, with or without IWQ ■ Lin ear staircase with high or low chroma m Muttiburst ■ External video, external audio ■ Interlaced scan Model 1251 51,195 NTSe Generator with RGB ■ NTSC color bar pattern ■ t Vp^p or variable composite video outpyt ■ RGB outputs ort BNC or 9'pin D'lype stibm i niatu re con nector ■ Composite sync, veriical sync, and horizontal sync outputs ■ I nta rl aced or prog ra s s i va scan Model124gA 5558 24 Deluxe NTSC Video Signal Generator ■ High accuracy htTSC color bars ■ TCXO master oscillator ■ RGB, Gen Lock, Circle, and Black Buret ■ Multiburstto a MHi. tOO%/&0^ level ■ Interlaced or progressive scan Model 126D Start working smartarr For details on the complete line of B+K PRECISION video generators or tot immediate delrvery, contaa your local distributor or: 0§J^ ^M^gj^Ji^Irf'fca 1 ' Domestic and tnterr^atipnal Sales Of% rrtCWV^^MIV 5470W.CoftlandSL.CNcago. IL6O635 mAi^^tHvamArvmMA.ctmP. 3i2-aB9-1448 • FAX: 312-794-9740 Shortwave Listening Guidebook by Harry Hetms The world is talking on shortwave radio, and here's the book thai tells you how to listen in! In directs nontechnical language, Harry explains how to get the most from your shortwave radio. Its 320 heavily illustratec^ pages are 11 lied with practical advice on: • antennas • when and where to tune • selecting Ihe right radio for you • accessories • reception lechniques Learn how to hear the BBC, Radio Moscow, ham radio operators, ships at ^^ea. even Air Force One! Includes hundreds of frequencies for stations around the wortd and the times you can hear them* Onty $16.95 pfu5 $3.00 shipping (CA residents please inciude TIZB MEtHmar Road sales tax}. s»ita isu san rK«go. ca S2 1 z i HisKText For inforTTiatiori only circle 77 on free informaiion card. For sales assistance circle 210 on free infortnation card. mount devices. According to Huntron Instruments, the robotic probe can set up and test any kind of component on a printed- circuit board faster than using a conventional "'bed- of-naiis ' test system. The Prober RP388, which requires the SfOODS troubleshooting system for operation, consists of a precision electro-mechan- ical probe and a software- controlled videonmaging system. The probe can be driven to the test point with approximately ± 4-miis ac- curacy and the Imaging system shows a detailed, real-time image of the board on the PC monitor Establishing a test routine and troubleshooting is a three*step process using the combination of the SfOODS and the Prober RP388: Teach the Prober the test-point locations: learn and store signatures of good components: and find feylty components by automatically comparing their signatures to the sig- natures stored on the PC hard dnve. On average, a PCB with 39 surface mount devices (14 to 20 pins per component) can be tested in less than 10 minutes, The Prober RP388 costs $23,000; the 5?00DS sys- tem required to operate it starts at $10,000.— Hunt- ron instruments Inc.. 15720 Mill Creek Blvd,, Mill Creek. WA 98012; Phone: 800-426-2965 or 206-743-3171; Fax: 206-743-1360. DIGITAL VOICE CHIP SET Electech Electronics' VCS-t870 allows circuit designers to easily add dig- CIRCLE 21 ON FREE INFOfMATtON CARD itrzed voice to their de- signs. The set consists of the 40-pin DIP VP^tSJO voice^processing chip and the 2rpin SF-700 filter module board. The chip features CVSD encoding at variable sampling rates for natural-sounding voice digitization. Its 8 bit bi-di- rectional interfaces is com- patible with most micro- processors. Digitized voice data is stored in extennal RAM or ROM. The SF-700 is an active band-pass (300^Hz to 3-4-kHz) filter module with pre-amp for microphone or line input signals. Specially designed to v^rk with the VP- 1870. it provides good voice quality and high reliability with greatly reduced compo- nents count, board space, and power consumption. Operation requires a single 3' to 6-volt DC power sup- ply The VCS-}870 digital voice chip set costs $16 in quantities of 1000. — Elec- tech Electronics. 1262 East Katella Avenue, Anaheim, CA 92805: Phone: 714-385-1707; Fax: 714-385-1708. DIGITAL MULTIMETERS. An enhanced line of low-cost, pocket-sized digital mutti- meters from Beckman In- dustrial include features ordinarily found only in more expensive units. For instance. Models DM5XL Train at HOME to be an Eiectmnics Technician \ As. ihe dcnvinct for computers and nutrtjprtH t*NM>iv in busifTCs^i, m^nutattLtringiind tommunic\irt(mv corvtitxues Ic* Rfow, so does rhe necnl kit cju*ilifiial technic kins, H's not unusual ior cKpenofiLiij technicians to Ciim iVom $30,0tK} to more thon $40,000 a VLMr. ' Now through Peoples Collegia oi lndepend*?nt Stud re's you tan mm for Ihi** eH'iting field wilhnut imerruptin>; your iol) or homt' liff. • Etectronicv & Microproce^sof Technnlogy • Industrial Elect ronics & Mkfoproces^ Technology • CommufticJitiQn^ Electronics wiih Miicri> prt>cei50f Technology • Computer Servicmg & Electronics Techrwlpgy « SpccUtized As^tate Degree In EEectrontct Technology Profcssiomt Equlpmerrl Is tncludnf Depending on the program you sekt l, yfw II pefiEect ^"Our skills using ihis advanced equifimenf. included in the price of (ytiion: • IBM-Compjiible Personal Compuier • Digital Multimeter ■ Digital Logic Probe • Elenco Oscilloscope • Portable Cellular Telephone l' S^iLtKr IrS. fiuri'^Li (il lAtmi Milieu) Peoples College iniroduLo suk:^ traming tirsis lo make your learning experierK:!* more comptete * Accelerated LeammR 5>'stem — a ^lentifically proven ^tudy system that Help^ yoix leam faster and ea^K*J than e^t-r hefofe. •Vkfeo Tutoi- Training Taftes — give yoo a pefmanent, visual rtcord or infofmaftve lectures and cfosc-up demonslfattons. • Ijtpenence Labs ~ protesstonatly designed experiments that give yotj hands-ori "bench" e^tp^rience. ■ Industry Certification Training Guide — provided with ftjur of our programs. Prepares you for mi nations you m^y take for your professional lit rnx' or certtficjiion. To help you get sttirtetf on your edutaiirjn. Peoples College has red 1/0x1 tuitt Stale Zip B Phone if Peoples College : Of I >i II MM N i ^ r > T i: p 1 1 s ^ 233 Academy Drive • P.O. Box 421768 , Kis&immee, FL 34742-Uhn , R0292 CIRCLE 197 ON FREE INFORMATtON CARD CIRCLE 22 ON FREE INFORMATJON CARD DMtOXL and DMtOXL each offer tO-amp current fusing to pnolect both the user and the meter safety test leads with shrouded input plugs and text points, a warning beeper when the test leads are placed in the wrong input jacks, large LCD numerals* and in- creased battery life. All three meters measure DC voltage to 1000 voSts. AC voltage (to 500 volts for the DM5XL and to 750 volts for the other two), resis- tance* and diode test, and have a continuity beeper Model DMWXL adds a fea- ture called the "Safety Tester." which detects and displays commonly en- countered AC and DC volt- age levels fnDm 6 to 220 volts. This feature works even when the DMM bat- tery is dead, ensuring that the user can always safely detect the presence of live voltage levels. Model DMfSXL also adds a logrc- measunement function that indicates the presence and polarity of TTL pulses up to 20 MHz, Models DM5XL DMWXL and DMtSXL digital multr- meters cost $34.95, $44.95. and $59.95. re- spectively. — Beckman In- dustrial Corporation. 3883 Ruff in Road. San Diego, CA 92123 1898: Phone: 619-4953218, SEMIANALYZER SIGNAL TRACER. The £03^590 Semianafyzer II from Elec- tronic Design Specialists allows the technician to trace audio, video, digital, or FG signals to the prob- lem area, while simulta- neously monitoring DC voltages along the way on its 31^^-digit voltmeter. Once the technician is in the suspected area, the in- strument will check semi* conductor devices in circuit and display the type, polar- ity. and condition of the de- vice in plain English. Dif- ferent tones beep to ORCLE 23 ON FREE tNFORNiATlON CARD indicate various problems. The Semianalyzer If also checks Zener diodes for their proper voltages, as well as neons. LED's. and capacitors for leakage, noise, and voltage break- down up to 175 volts DC using a built-in "Hi-Pot" tester. For repairing remote controls, an optional in- frared detector probe is available. The Semianalyzer fIcomBs with a thnee-year limited warran- ty and a 60-day money- back trial period. It is also available in kit fomn, without the 60-day trial period. The Semianalyzer ft costs $399 fully as- sembled, and $299 in kit form, with cabinet. — Elec- Ironic Design Specialists, Inc. 275 Rock Island Road. North Lauderdale. FL 33068: Phone or Fax: 305-720-4497. R^E ClRt^LE 50 OM FREE WFORIlATlON CARD An ETCHED circuit board from a Printed PAGE in just 5 Hours The ER'4 PHOTO ETCH"-' KIT fjivos you (he tools, materials and chemicals to make your owf\ circuit boards horn the artwork oftnted in magazines like this one, Yoy can also do origmat IX aft using the enclosed patterns, tapes and draftmg fttm Or try the DIRECT ETCH^'^ system Ulso incliided) to inake single circuit boards without artwork. Vou II need a reflector photoflood and a UV light source (or sunlight } ^iVhy search? Gel an ER- 19 bulb sot with your ER'4 Bulbs use an ordinary 120V socket The ER-4 and ER-t9 are slocked by electronic parts distributors or ardef d irect Add S4 50 for sh ippmg K V and CA residents must add sales (ax . ER^ PHOTO ETCH SET S38 00 ER-19 LIGHT BULB SET 16.45 DATAKCorpordtion • 85 Freepon Blvd. • Sparks, NV 89431 anCLE IffT OH FREE INFORMATION CARD NEW LIT Use The Free In formation Card for fast response. YOUR NATURAL RE- SOURCE: 1992 ANNUAL CAT- ALOG; from Jameco Elec- tronic Components and Computer Products, 1355 Stioreway Road, Belmont, CA 94002; Phone: 800-831-4242; Fax: 800-237^0948; free. This year's catalog from Jameco. printed on re- cycled paper carries the theme "Your Natural Re- source." Intended as a complete source book for electronics hobbyists and computer enthusiasts, the 90-page, full-color catalog includes descriptions of more than 3000 products, CfRCLE 40 ON FREE INFORMATION CARD from electronic compo- nents to test and measure- ment equipment, from ca- bles to complete computer systems. Other features of the catalog include educa- tional information and a RAM cross- reference guide. To further assist customers in making pur- chasing decisions. Jameco offers 24-hour toll-free order placement and toll- free fax and BBS setvjce. TECHNMOOL CATALOG 41; from TechnhTool Inc., 5 Ap- ollo Road, P.O, Box 358, Plymouth Meeting, PA 19462; Phone: 215-941-2400; Fax: 215-828-5623; free. The 240 pages of this catalog are filled with an as- sortment of tools , tool kits, and test equipment that in- cludes more than 18,000 items from 850 manufac- turers. Electronics profes- sionals and hobbyfsts will find items ranging from electro-mechanical and as- sembly devices to elec- tronic, telecommunication, and field-sen/ice tool kits. Also featured are full lines of tools, equipment, and accessories for computer maintenance and for the fast-growing field of sur- face-mount technology. Static control and clean- room items are included. Several new items are high- lighted. Including 100-MHz monolithic oscilloscope CIRCLE 39 ON FREE INFORMATION CARD probes, the ESD heat gun. the Fluke 88 Automotive Meter, and the kit bag with conductive plastic cabinets for easy carrying of small electronic parts. TEST INSTRUMENTS ANA- LOG & DIGITAL; from Sim- pson Electric Company, 853 Dtindee Avenue, Elgin, IL 60120-3090; Phone: 708-697-2260; Fax: 708-697-2272; free. This 44-page, four-color catalog features Simpson s lines of hand-held and benchtop multimeters, CIRCLE 38 ON FREE INFORMATtON CARD special function meters, clamp-on testers^ and other specialized testers for electrical, electronic, and environmental applica- tions. In addition to that equipment, the catalog covers special-function ohmmeters. voltmeters, and ammeters; insulation and temperature testers; testers for microwave and AC current leakage; and sound- and noise-measure- ment instruments and tele- phone-Industry test sets. Capsule descriptions of each item, along with Ifsts of features, ordering infor- continued on page 87 GET YOUR AMATEUR HAM RADIO LICENSE! The New Code-Free Technkan License Is Here! When you pass a 55 question rtiuftiple-dioice test you can: ^TrGnsmit over huncireds of miles wilh handheld two-way radios. Why pay cellular charges for your personal or emergency com- municotions. ★ Enjoy oil Ainateur privileges above 30 MHz dl the my up to the uncharted frontiers of microwave ond amateur television! ★ Access satellite communicptian— talk to aslronauts in orbit . . . make friends through o fleet of amateur satellites. Talk to friends nearby and in faraway places using FM voice repeaters. ^ Use your personal computer ond radio modem to talk to other hums or exchange computer data ond much more! Send for FREE details on how you can pass the Amateur Radio exam . . . fast! Write for FREE mformation toda^. Amateur Radio license Troinmg PO Box 26348 Son Francisco a 94126 0) to 27 Take any when you join the 3158 $2£.95 This book offers up-io-daic iniimciions for troubleshootiiig and rcpsiinrtg dl tnapt brands of cq«ipmc(il» wiib hundreds of diagranu. sprci. and ^homiici^ Coven TVs. VCRs. CD play- ers, and much more. MO pp. m3 $22.95 WHh ibb guide in Hand, readers can produce cfi^p> conci^ papers lb:a! wtfl Icuvc their in^ tended nmk on cummiticcs. pancK. hiwds diraiors. and customers. in>irueuonf on reports, prt»p<»*jK. bt»oLi. and oml presentation.^. 144 pp.. 37 iltus. ' J I •'S ^ll 9255 S97.50 '*Ouisianding. ejitcnsive reference to currcni lechnology of electronics. Covers t%ef>ihin|i^ frtim principle!* tn ap- phcaltons." —Computer [kx>k Review 2,528 pp.. 1.800 Ciiunts as J 1M16 139,95 Design tigJ^ier, mor& complex circuits, on lime 2nd on budget with diis book, one of the Vml to provide a thorough coverage of all aspects of PCS design, including CAD. 320 pp. CiJjmfj oj 2 ELECTROKIC POWER CONTROL " ill 1 I I MCHVlCAl 'llOIISSIOyi lutii iiiii 585885-1 $29.95 Shows how to reposition yourself as a kcv player in today's competitive job market - Communications and interper- sonal IS kills. Technology evalua- tion, career positioning, interviewing strategics are jusi a few nf tlie arcsis reviewed. 330 pp,» ntus. UNEAR IC HANDBOOK : 5158 $60.00 A Gl A NTT 'Tircuil Book" of over 700 of the most widely - used, slate-of-the-an electronic and integraictl cin.niits ever com- piled in jj Mingle wturcc! The perfect sourcebook for all levels of electronics practitioners. 738 pp. Coums as 2 3147 $3g,95 Provider a rendy source of basic information on ui^ing progr4m- mablc coniri^llers to achieve a wide viiriety of manufacturing go;ils. Vtni'il ftiid nt>wcluiTts uml Mcp-hy-^tcp cvplsmnlioni^ to develop, invprove, ntuli monitor procesji cotttrol. 304 pp.. I R7 ill Lis. CituniK m 2 The cssenttal reference for all electrtcal cnginocn Complete- ly revised and updated, thb classic handbook covers the generatiO'n, transmiShSion, distribution, control, conserva- tion, and applicatkm of dcctniad power, 2,416pp.. I,3R8 dins.. 430 Ublcs. 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PresenLs slale-of- I he-art approaches U> analysis, irouhlcshooting^ and impletncn' lation nf new solid-staEc devices. An excellent iiDurccbtiok and a valuable edition to an engineer's libniry. 27Z pp. 2672 $49.5« Thb one- Mop sourcebook bridges Uie gap between data books and ihe designer'^ .search for the right component. Covers how linear ICs arc fabricated, hnw they work, what typc:>^ arc avaihihle, and techniques for designing. 624 pp. \ Electponjcs 00J9S7-7 S49.9S Wiinen for technical personnel, engtaccrs. managers, and opermrs, this is a pisctial guide to design, irttpkmentatkm. and maimcnanoe of cabk TV systons, includs, an overall introdtictioiv to standard NTSC and HDTV systems. ■ICO pp. Cotmli as 2 3589 £27.95 A poetical toolbox refcrawt for anyone tn the dectrooics field. 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Jack permits ''chain" hook- ups. #274-734, Set of 2/1.59 (2) Nylon BInrfing Posts. #27^-662 .... Set of 3/1,59 (3) Micro*Cllp Jumpers. 20" long. /^27e-0r7 , , . Palr/3.49 Super- Bright Strobe Tube. Perfect for photo replacement, hobby projects and experi- ments. Trigger; 4 kV. Anode: 200V min. Bulb is about IV2" long and has leads. 1^272-1145 3.29 (1> High-Speed 12VDC Mo- tor. Up !o 15.200 RPM* About 2- long. #273*255 2.99 (2) Low 'Voltage Motor. For science projects and sotar power demos. Requires Vh to 3VDC. #273-223 99C (1) Lead-Free Solder. 96% tin, 4perClocks eight modes when a digit must be updated, the LED segments representing its old value are di* mmed as the segments for the new value become brighter. Likewise, each LED in the light chaser fades off rather than turns off. This animation is rather relaxing to watch. These display effects are ac- complished by a mixture of mul- tiplexing and duty-cycle modu- lation. The sev^en-segment dis- plays are all common-anode types* so each digit has its own anode-driver transistor In typ- ical multiplexed-display fash- ion, the cathodes of correspond- ing segments of each digit are connected together and share a common driver Like any other multiplexed display when the segment data for a digit is placed "on the seg- ment data lines, the anode driv- er for that digit is activated* and the seven-segment display lights to exhibit the appropriate digit. All the other digits are off at this time. After a short period of time (L83 ms) the segments are turned off via the segment lines and the anode driver is de- activated. The anode driver for the next digit is then activated, the segment data for that digit is placed on the segment lines, and the process continues until all the digits have been lit. Since the human eye is too slow to see the digits turn on and off, it ap- pears as though they are all on simultaneously- Multiplexing the digits in this fashion re- duces the number of pins on the microcontroller needed to con- trol the LED displays* H\perClocks fading effect is created by modulating the duty □ O UU o □ u □ ■r-f: 1^ f] JO n u J r j O g o 'I * * II ' ' — 'f\ r^— h < ( \) M < 1 '.V 1 1 il ii [(# — -^v ^1 FIG. 1— HYPERCLOCK S TIME DISPLAY {a} is unique in that it not only displays time normaily {b). but It can indicate minutes left to the next hour(c)* and blanks the minute displays on the hour {d). cycle of the segment enable sig- nals. When a seven -segment display is enabled* the segment data lines spend part of the time in states corresponding to the current digit to be displayed, and the rest of the time in states corresponding to the next or "future" digit that will be dis- played. Each lime the digit is enabled, the duty cycle will favor the future-digit data more and more, until only the new digit is displayed, and the process re- peats each lime the display must be updated. The microcontroller At the heart of the HyperClock is an Intel 8749 microcontroller. It is programmed to perform a variety of functions, namely: display multiplexing, time- keeping, receiving switch in- put, coordinating the hour and alarm chime, and initiating a power-fail mode that permits the time-keeping functions to continue while blanking the display to conserve backup-bat- tery power. The 8749 has 2K of EPROM. 128 bytes of RAM* 24 L/O pins, a programmable 8-bit timer* and an interrupt-conlrol structure. The custom-program placed In the processor to create Hyper- Clocks special effects exten* slvely exercises all of the chips features; Fig. 2 contains a sim- plified flow^ chart for the Hjper- Clock program. The program is shown divided into two sec- lions: an interrupt routine and a main loop. The interrupt routine is mainly responsible for taking the segment data from the seg- ment-data buffer in the micro- controller and placing it on the display-control lines in a multi- plexed fashion* The interrupt that initiates the routine comes from the 8749s internal timer, which has been programmed to execute the interrupt every 1,83 INTERRUPT HOUTlfJE START INTERRUPT ROUTINE AFTER EVERY 1.83m$ MAIN^FROGRAM LOOP EkAfVK (U5PLAV 1 UPDATE IE DD TH£ SEGMENT ISPLAY FROM | DATA BUFFER | E^JABLE NEXT DISPLAY DtGlT 1 SAfJiPLE LINE CYCLE FROM 1 LINE INPUT 1 SEGMErfT Dm ffiOMKJFFER ( I I 1 i I RETURN TO MAIN PROGRAM I 1 1 I" SEGMENT ^> [ DATA [ I BUFFER I -f I U SEGMENT DAIA TO BUFFER YES UPDATE LE DATAE D SEGMENT 1 BUFFER 1 rUPUT KEY SWITCH ROUTINES FDR PROGBAklMING CLOCK OPERATION CHIME SOFTWARE FUNCTIONS 1 ALARM SOFTWARE FUNCTIONS | FIG- 2— HYPERCLOCK'S SOFTWARE can be broken down into two distinct code segments: a clock-scheduled interrupt routine, and a main -prog ram loop. nis. Using an inter nipt -pro- gram segment in this way al- lows the display's fading elTect to appear gradual because the process of updating the display occurs at regular interv^als. This routine is also responsible for checki ng a powerl i ne-freque ncy input on the microcontroller to determine if a powerl inc cycle has passed. If so» it informs the main loop of the program. The main loop keeps track of the number of cycles that pass so it knows when to update the segment-data buffer or Initiate the alarm or chime. If no powerl ine cycles are detected, the main loop assumes AC power has been terminated and puts the clock in power- fall mode. In that mode II shuts off the display and allows the nii- croeontrolier to "invisibly" keep track oi' lime via a 6-MMz crys* tal. The main loop also pro- cesses input from the clocks switches (well talk more about that later). For all that goes on inside the microcontroUen the functions assigned to its pins by the Hy- pe rClock program (see Fig. 3) are relatively easy to under- stand. Lets take them one group at a time. The pins labeled a through g and ui* (pins 12''19) in Fig, 3 are the outputs for the display-seg- ment data. They indirectly con- trol the cathode drivers for the multiplexed display. Similarly, ■ / XI n A RESET 0 + 5mTS c 50/^ D UHl E SWl F SW2 G SW3 DP SW4 GEO SW5 DEI SW€ 0E2 SW7 DE3 CHIME DE4 GROUND M 1 <1 4 13 5.2^.40 14 15 A V 16 If Til Tf3 la C3 19 in 21 n J 1 22 111 23 33 24 a4 38 7.20 FIG, 3— THE PINS ON THE 9749 micro- controller are assigned various funC' tions by the HyperClock program. the outputs labeled deo-de4 (pins 21-24 and 35) control the anode drivers for the display Ha demultiplexer chips, which well discuss later The pins labeled si^z {pins 27-34) are used as function- switch inputs. The switches connected to those inputs (rMSPLAY MODE. DISPLAY DATE. DIS^ PLAY ALARM, INCREMENT HOUR/ MOfVTH/MODE. INCREMElsrr MINUTE/ DAY. SNOOZEvTIDE ADVANCE, and ALARM TOGGLE* respectively) ac- tivate various chip functions by grounding those pins, A com- plete explanation of the switch- es' functions will be presented later. Low-going pulses from the pin labeled chime (pin 34) acti- vate the chime circuit, which is composed of discrete compo- nents. The microcontroller trig- gers the chime circuit with a 12.8-ms wide low-going pulse at one-second intervals. When not in alarm mode» the chime sig- nals the hour by chiming an ap- propriate number of times, and signaJs each half-hour by chim- ing once. When the microcontroller is in the "alarm" mode, the chime circuitry is used as an alarm an- nunciator. In this mode the clock does not chime on the hour and half hour That per- mits you to use the HyperClock as an alarm clock without the chimes disturbing you until the appointed time. El 6 C83 MS V m . u IT If f f C17 Vv Lisniu. »9 an 1 i m !2_ T -at ti CM 1 CP? t: G d U U ma. 4— THE HYPERCLOCK DISPLAY is controlled by only 13 data Jines from th© miCFDcontroHer. The LINE input (pin 6) is used by the IC to accept a 50- or 60- Hz square wave. The square wave is used for time keeping and to detect AC*power failure as mentioned earlier. The 50Hz/60Hz input (pin 1), teUs the 8749 what frequency to ex- pect at the line input. If pin 6 is low, the 8749 assumes the line signal is at 60 Hz. but if that pin is high the 8749 prepares for 50-Hz operation. As its name implies, the RESET input (pin 4) initializes the microcontroller. A low at that input will erase all modes and settings previously entered. The XI and X2 inputs (pins 2 and 3) need to be connected to the 6-MHz crystal, XTALl, men- tioned previously. Last, but cer- tainly not least* are the 5-volt power inputs (pins 5. 26, and 40} and the grounds (pins 7 and 20), Those inputs of course, are self explanatory^, The display circuit While tiie microcontroller does a great deal, the H^-per- Clock requires some additional circuitry to make it a complete timepiece. For example, the mi- crocontroller cannot provide nearly enough current to drive the LED display, for that reason additional anode and cathode drivers were included in the de- sign. They are shown along with the other display components in Fig, 4. The control signals for the LED cathodes originate from thcA-G and orpins of the micro- controller. The A-G signals are sent to a ULN2003 buffer/driver (IC7) which contains seven high-current drivers. Each out- put is capable of providing 500 mA of peak drive current. Since the ULN2003 contains only seven of the eight cathode driv- ers required, a Darlington driv- er was made out of two 2N2222 transistors to drive the dp line. The DEO through de4 outputs generated by the micro- controller are decoded bv two 74 LSI 45 decoder/driver IC's (ICS and IC6). Only one decoder output is driven low at any time. Each 74LS145 output supplies current to a 2N2907 drive tran- sistor that sources current for the anodes of a group of LED's or a display digit. Note that there are additional LEDls to provide an AM/PM in- KTAL1 r CD 1 L J2EXTERNAL SWflCH CONNECTOR 32 31 MJNUTE olS4 29 S7 S6 S5 S4 S3 B%2 2I_ DIG m\ ,23 DIG EHa ^ 3 24 DIG IH3^ ,35 DIG m\ HOUR \Mom\ mm lC2b DIG £N(0^41 R1 47K ce Hf- TO DISPIAY [SEE FIG.4) BATTERY CLIP "a: 9 csJc C15-L cie-L C6 R7 m CJO 47k:^ ^''^ RIO _ 47K Cl2q^ 560pF — \yr— nil 47K JU2 CHIME VOLUME JUMPER FIG. 5— THIS SCHEMATIC DIAGRAM FOR THE H YPERCLOCK crrcuit (less Ihe display components) shows the support circuitry required by the microcontroner. d teat ion (LED61). tell you if the alarm-mode is active (LED62), and provide a winking second display (LED63 lo LED65). That's all there is to the display circulL The remainder The most noteworthy of the clock's remain in|* circuitry (shown in Fig, 5] is the chime circuit. When the micro- controller generates a low-going pulse on pin 34, il activates 919. That transistor then pro- vldcs sufficient current to drive Ql into saturation. With Ql on, the negative side of C13 is effectively grounded, which causes it to charge. Wlien Ql is turned off. C13 discharges through a 470K resistor (R13K The resistor/capacitor com- bination has a time constant of 0.47 seconds. The exponen- tially decaying signal produced by the discharge is buffered through a unity-gain amplifier [iC3-a) to a 1N914 diode (D3K The cathode of D3 is con- nected to the output of a 50% duty cycle 5-kH/, square-wave oscillator consisting of IC2-a, R7, CIO, and Q2. TVansistor 92 serves to provide a dynamic pull-up for that oscillator since ttie LM393 is an open-collector type comparator. The 5-kHz DO Q. 9 m 37 PARTS LIST All rBsistors am V4-watt, 5%, unless otherwise indicatect. R1. RtO-R12, R16, R17— 47,000 ohms R2, R3. R5. Rt4, R$5, R18^R32, R4i_R57_^700 ohms R4, R13, R5a^70.000 olims R9— 2700 Ohms R33-R40— 330 ohms, l^wall. 5% Capaeitors CI, C2— 20 pF ceramic C3— 1000 16 volts, electmtylic C4, C5, C15. C16— 0.1 [lF. ceramic C6— 22 ikF. 16 volts, electrolytic C7— 2.2 plK 16 volts, electrolytic Cfl. C9— 0.01 jiF, ceramic CIO. C14. C1 7— 0.0033 ^R ceramic Cit C12—560 pR ceramic 013^1 ^iF, 16 volts, tanlatum Semiconductors IC1~IM340T*5 5-volt regulator tC2— LM393 dual-comparator square wave present at the emitter orQ2 is clamped in am- plitude by the buffered expo- nential waveform from lC3-a. so the 5-kHz signal decaj^ in am- pLllude in step with the dis- charge of CI 3, The decaying 5-kHz signal is fed through C14 to a second- order low-pass filter tuned to ap- proximately 5 kHz. The filter is composed of a LM324 op-amp (IC3-d), CIL C12, C14. RIO. and RIL It removes the high-fre- quency components contained in the decaying square wave to smooth it out- From there the signal is passed to two more op- amps (IC3-b and IC3-c) that form a push-pull amplifier, which provides the piezo trans- ducer with a 10- volt peak* to- peak drive signal. While the output signal is not exactly a pure sine wave, the au- dible result sounds pretty much like a small bell If you feel the chime is too loud, you can elimi- nate half of the push-pull ampli- fier by jumpering one side of the transducer to the 5-volt supply which is available via JU2, The entire circuit receives power from a 9-VAC wall-mount transformer The 9-VAC supply is fed to a full-wave bridge rec* tifier and filtered by 03 to act as an unregulated 12-vo!t DC sup- IC3— LM324 quad-op-amp IC4— B749 microcontroller with Hyper- Clock pfogram ICS, IC6— 74LS145 l-of-S decoder driver (07— ICLN2003 hjgh-cun^nl driver D1, D3^INgi4AdJ0de D2— m4001 diode Q^.02. Q17, 018— 2N2222 NPN transistor 03-^16. 019— 2N2907 PWP transistor BR1— 1-amp, 50 volts PIV bridge rectifier DISP1, DISP3— Panasonic LN524RA or similar 7-segment display (for the smaller digits) DISP2— Panasonic LNS26RA or similar 7-segrT^enl display (for the larger digit) LED1-LED6&— {jght-emttting diodes Other componenis XTAL1— 6-MHz crystal Tt— 9-VAC 500-mA wall-mount transfornier BZ1— piezo transducer S1«S7— miniature momenlary-contacl pushbutton switch B1— 9-voil battery ply The 12-volt supply powers the display circuitry, op-amps, the comparators, and an LM340-5 (ICl) 5-volt regulator The regulator in turn powers the 5~volt supply line. If AC power is interrupted, a 9-voll batter)^ connected to Jl sources current to the regulator to keep the HyperClock func- tioning. If you plan to unplug the clock for any length of time, the battery should be discon- nected to conserve its life. A BIT ABOUT TIDES Predicting the tides in any given locale is not a simple job. Tides are affected by many cyclic astronomical forces: the deciination in the ottWs of the moon and sun relative to a potnt on the Earth, and the local geography of the coast line tn the area in which you live, to name a few. HyperClock predicts the tidal levels from the most predominate of these forces, the moon. The moon requires 29,53 days to ort>it Earth, and that combined with the 24- hour solar day causes a high and low tide in every 12 hour and 25.5 minute interval. HyperClock tracks the moons prtmary affect on the tide. You can find out about the level of local tides in your area from your newspaper or library. The infomnation can be used to initially set the tide indication on your HyperClock to a low or high point. From then on the graphic display will be an aid in the determination of the relative level of the tides in your locality Mlscellanious: T-220 style heatsink. PC tJoard or perforated construction Ijoard. battery clip, shortir^ blocks* solder, etc. Kote: The following items are avail- able from SkiTronix. P.O. 96fi5, Spokane, WA 992D9: • A pre-programmed HyperClock 8749 microcontroller with firmware license— S10.QO. • An etched and drilled PC board— S25. 00. • The foil pattern artwork suitable for conversion lo film — $3.00. • Software on floppy disk— S5.0O postpaid • A complete kit of parts Including the PC board, programmed 8749 IC; LED's, displays, electronic components, and the wall-mount tra n s f o rme r— S7fl .00 . A detailed d rawing of the HyperClock wood case, wilt be supplied with all orders. Please Include $3.00 for shipping and handling, Wash- ington residents must include an additional 7.9% sales tax. The line input (pin 6) of the microcontroller cannot be driv- en directly from the 12-VAC wall transformer. So the trans- former signal is conditioned by a Schmitt-t rigger circuit to gen- erate a suitable square wave. First the signal's amplitude is reduced by a v^oltage divider consisting of Rl and R58, and its positive excursions are lim- ited to about 5 volts by DL The limited signal is then sent to the inverting input of the LM393 comparator. Positive feedback is applied to the comparator's non^invertlng input by R4 to prevent it from generating false signals. The comparator drives the microcontrollers line input with the resulting square wave. Construction In order to build a Hyper- Clock, you 11 need a pro- grammed 8749 microcontrolien A preprogrammed and tested microcontroller is available from the supplier mentioned in the parts list. The executable code to program an 8749 is available from the RE-BBS (516-293-2283, 1200/2400, 8NiK as a file called HYPER. HEX. The file is sup- plied in Inters Hex format, which is directly compatible with most EPROM program- L€0€0 LED! ® )^ D!SP3 , LE&30 f\G. 6— DISPLAY-SrOE PARTS-PLACEMENT diagram can be used to Jocate most of the HyperClock's components. mers. The software Is also avail- able on floppy disk from the source mentioned In the parts list. A 6.5- X 6.5-lnch octagon- shaped PC board is also avail- able from that supplier lo help you assemble a HyperClock of your own. If you wisli. you can make your own double-sided prlnted-circuit board from the foil patterns Included in this ar- ticle or using artwork from the supplier listed in the parts list. Of course, you could even use a point-to-point wiring tech- nique « so well discuss that briefly later on. Figures 6 and 7 show the parts-placement diagrams for the HyperClock (6 shows the display side and 7 shows the solder side) for those of you that will use a PC board. All compo- nents, except for the wall- mount transformer, are shown mounted on the circuit board. Note that the switches can be placed on either side of the board, depending on the cab- inet you wish to place the clock in. There are some additional connector pads on the board so you can run wires to the switch- es should your cabinet design require that they be located off the PC board. Figure 8 shows a completed HyperClock board. The design readily lends itself to many different project cases. However make sure that the cabinet you choose has some openings in the back to allow a little cool air to flow around the clocks 5-volt regulator and heat sink. If you like the case used for the prototype, you can build one out of a length of wood molding as the author did. TO FIG. 7— THIS PARTS-PLACEMENT DIAGRAM shouM be used to posttlon the regulator, battery, a capacitor, and th& switches. The PC board was designed to work w ith many different dual- digit displays, so you don t nec- essarily have to restrict j^ourself to the Panasonic units men- tioned in the parts list. Just make sure that whatever you use Is a pin-for-pin same-size re- placement. If you do use the rec- ommended units, be sure to raise the two minute displays up from the board so that their viewing surfaces are flush with that of the hour display. Lastly, the PC board provides some holes for wire ties to hold the 9-volt batteiy and the wall- mount transformer leads. You should take advantage of them. Remember to install the 9-volt backup battery and connect JUl and JU2 to select 50- or 60- Hz operation and the volume of the chime, respectively. Wlien you connect the clock to power it should come up at 12:30 AM and will be ready to accept the current time, alarm time, date, and the *tide level If desired. If you run into any diffi- culty, you may find some of the troubleshooting tips provided in the following section useful. Howeven if all is well, you can proceed to the "operating" sec- tion to prepare the clock for use. Point-to-point wiring Working with perforated con- struction board and point-to- point wiring gives you the free- dom to design your own display layout. One nice alternate de- sign would be to place the 60 LED s in the form of a full cycle of a sine wave, especially if you set the clock to display the tide level An early prototype of the clock was built using wire wrap. Re- gardless of the wiring tech- nique, you should invest in a large enough piece of perforated construction board (at least 6 x 6 inches) so that you can make your custom display with plenty of room to spare for all the sup- port electronics. Furthermore, when you are shopping for the hour and min- ute displays, select minute dis- plays thai are somehow dis- tinctly different than the hour display. That will make the dis- play more easily readable in the "minutes before the hour'' mode. It is also suggested that you don*t place the display compo- nents on the same side of the board as the heatsink/regulator assembly, C3. and the 9-voll battery. Doing so would in- crease the profile of the display side of the board, forcing you to place the LED lens at an un- desirable distance from the dis- play components. Aside from those sugges- tions, layout is not critical, so if you observe good construction and wiring techniques you should not have any problem getting the clock to function. However, if you should encoun- ter some difficulty, the following hints ought to help: • If no LED's are illuminated when you apply power, first check the unregulated supply for a minimum of 10 volts DC. While only 2 to 3 volts of over- head are required to operate the 5-volt regulator, at least 10 volts Is required to drive the LEDs sufficiently. • If the power-supply circuitry is okay, check the wiring around the LM393 (1C2) from the bridge rectifier and going to IC4 pin 6; the microcontroller looks at that line and if there is no line frequency at that input, the clock will shut down the LED drivers [as we explained earlier). Since most of the wiring in the clock runs between the LED drivers and the LED s. it is likely that you could have made an er* ror in one or more of those con- nections. If you observ^e that any active LED segments do not form numbers, then you should check the connections from IC4 to IC 7 and the corresponding connections to the cathodes of the LED displays. A mistake be- tween IC4 to IC5 and ICS will make the displayed digits and/ or seconds appear out of order. An error in wiring from the out- puts of the 74 LSI 45 s to the -ISA TABLE 1— MODES AND THEIR FEATURES FIG. A FINISHED HYPERCLOCK,The PC board makes assembly neal and Straightforward. Feature Mode 0 1 2 3 4 5 7 Faff inn t Jryiatf*s • • • • Plain Updates # • • Before-The-Hour Display • • Plain Display • • • • Trde Ught Chaser • • • • Seconds Ught Chaser • • m • |- m INCHES -j [- m IfiCHES ^ THE DISPLAY-SIDE FOIL PATTERN can be used to generate one THIS FOIL PATTERN can be used to generate the solder side of side of the clock's PC board. the clock's PC board. driver transistors^ which con* nect to the LED anodes* will cause the same effect. Operation The functions performed by S4 and S5 in the HjTperClock depend on the state of the three display switches (SI through S3], tf none of the display switches are depressed, press- ing S4 advances the current hour displayed and pressing S5 advances the minute display That is how you set the time. Pressing and holding down SI (the Display-Mode button) causes the clock to display the number of the current operat- ing mode, which can be aJtened by pressing S4 (S5 will do nothing). The various operating modes and the features they support are listed in T^ble L If you depress and hold switch 82 (the Display-Date button) the current month and day are displayed. With that switch de- pressed, the month and day can be advanced by pressing S4 and S5, respectively. Activating switch S3 will cause the clock to display the time the alarm is set fon By pressing S3 along with S4 you can alter the hour setting, and by pressing S3 and S5 simulta- neously you can change the minute setting* Moving on to the last two switches, the Alarm Toggle switch (S7) determines the state of the alarm and the hour chime of the clock. For example. on power up the hour chime is enabled and the alarm is dis- abled. If S7 is pressed once, the alarm is turned on and the hour chime is disabled. Depressing the switch again w^ill turn off both the alarm and the hourly chime. The Snooz&Tide Switch (S6) ji has a dual purpose. If the Hyper- §" Clocks alarm v/as armed and ^ goes off, that button will silence the alarm for an additional ten ^ minutes. You can forestall the alarm in this way as many times g. as you like. If the alarm is dls- 9 abled. and the clock is in a mode w that supports the tide-level dis- | play (modes 4 through 7), press- | ing S6 will advance the tide indication on the 60-LED dis- play to set its position. R-E 41 I IT 42 WARNING! Piease note that unauthonzea v*'jre ana electronic communications interception and interception ot oral commu^iic^tiDns IS Illegal under Federal and State Law. In addiUon Federal Law renders itiegai ttie intentional manutactunng. assembling, possessing, or selling any electronic, mechanical or otiier device. Iin owing or having reason to knovi/ that 1 he design of such device renders it primarily useful for the purpose of surreptilious intercep- tion or wire, oral or el&cironic commL- nications. Federal law imposes both civil and criminal penalties for vioiations of the applicable statutes. Thus, the use of the Scanner Converter described in this article is intended lor and should be re- stricted to educational, scientific, and or inlormatTonal purposes, This is not in- fended to constitute legal advice and readers are advised to obiain mdepen- dent advice as to the propriety of their use thereof based upon their individual circumstances and jurisdictions SCANNER CONVERTER J Upgrade your scarifier to receive signals in the 800-900 or 900-1000 MHz bands! WILLIAM SHEETS and RUDOLF E GRAF Tlir: HfiU'lUOu MHZ UA'Kn OF KRK- quencies. lyin^ in the portion of the radio spectrum known as the UHF band, has recently be- come populated with many sig- nals of interest to the shortwave listener (SWL) and scanner hob- byist. Originally, the 800-890 MHz portion was allocated to UHF TV broadcasting. Lack of interest in these frequencies (formeriy TV channels 70^83) and a pressing need for spec- trum space was largely respon- sible for re-allocatlon. The port ton of siieclrum now in- eludes business radio, public^ safety (polla% iirt\ etc.) and^^cti- eral-purpose two-way radio. The lower portion is largely used by cellular mobile radio telephone sendees. The upper pt>rl ion {above 900 MHz) is used for two-way radio, industrial ra- dio, amateur radio, and mis- cellaneous purposes, such as wireless video and audio links, studio to transmitter (STL) links, and v^arious Fart 15 ap- plications t low- power license- free uses], and even more! Fig- ure 1 summarizes the current frequency allocations. The frequencies are almost in the microwave region. Until re- cent ly. receivers for this l^and wert! scarce and usually special- [)UT*i)r}sc types, in the past few years, a number of cominunicn- tioiis receivers liave been made available, covering from around 25 MHz or so up to over 1000 tVlHz, Some of the more expen- sive scanners cover portions of the 800-1000 MHz ranoe. while others block out the Ijands, Now you can build a converter that will allow tlie reception of signals from 800-1000 MHz on any scanner that covers fre- quencies in the 400-500 MHz range. The availablUty of high- performance transistors and Monolithic Microwave Inte- f^rated Circuits (MMIC'sK to- getlier with very small compo- nents such as chip capaciiors and prepackaged mixer avssem- S>[ies. have made lliis feasible. The antenna shown in Uie (>[>e^li^g photograph is cut s[)e~ eilieally f[)r (he 800-Mi^z band. Its available from Ihe Cellular Securitv Group, 4 Gerring Road, Gloucester MA 01930, Contact them directlv for infor- low OIGiTAl COMMU^fCATIQr^S WEAK *. SIGNAL WORK BEACONS EARIH-MOOM^EARTH SPACE COMMUtilCATlONS J- 900 902 904 mm SIMPLEX FREQUENCY 906.SMHI mAJtm -TElEVISrON- p — ANO- REPEATEHS WiDEBAfiD, -EXPERiMEtJIAl-* Am SPREAD ^ECTRUM AMATEUR TILEVISIOH j X 910 J L pimrc h— SAFETY. MUNlCm. FlRE-POtffiE S51 8?0 PUBLIC ^SAFETY* iOTELEPHOflEl fjUmiCPAL, RREmCE 395 MQ8IIE [ RADtO- :ElIPHOME-n t -U 300 RfPEATEB OFFSETS USUAUY 45i^H/ CHAHNf L SBvaMG 25 OR llSkUz 9T6 ?20 PART t5 DEVICES VIDEO DATA LINKS BUSfKESS I MISCRAOtO COMMUHlCATfDKS STl (BROADCAST) LtriKS AfilATEUH mm DETAIL f902- 3Z8MHj} fUSAI AIRdlAnAm) fiAvrSAnoM AMATtUB ^ BAND RG. I^THE 800-1000 MHZ UHF BAND has many signals of Interest to the shortwave Itstener. Here Is a summary of the current frequency allccattons. flOOMHz-lGKz ANTENNA NF^UdB 01 Z5t37 GASFfT ISTRF S).&2-3.S2'& GANGED TOGFTHER RlTta -3dB NI^5dB tCi MMIG ?ND RF AMP BANDPASS FILTER '3tlB FILTER 400ORSOOMm FILTER la - iflVAC 02 XTAL OSC AND DOUBLER RECT«R 03 OUAOHLfPLER- QUINTUPLER X EC2 12V RFG t !2V REGULATED TO AIL STAGES FIG. 2— BLOCK DIAGRAM, A GaAsFET feeds a double-tuned filter and a MMtC RF amplifier that feeds a second double-tuned filter. That feeds a double baianced ml )ter, or DBM. The DBM is also fed with a local oscillator signal of either 400-MHz or 500* MHz. AND MAY VARY ftJANY mBi SYSTEM Ma mation on that and other vari- ous UHF antennas. The converter described in this article offers excellent per- rormance (about 0.15 M.V/12dB SINAD — slgnal-to-notse-and- dis tort ion-ratio — sensitivit>' for standard 5-kHz FM)* having an NF (noise figure) of about 2 dB, a gain of 20-25 dB. and an out- put frequency of 400-500 MHz. By simple tuning adjustment it can be set up for 800*900 or 900-1000 MHz ranges and op- timized for any 30-40 MHz seg- ment in the range. It will work well over the entire lOO-MHz range if circuits are stagger- tuned, with only slightly re- duced sensitivity Applications of the converter are as follows: 1. Monitoring 800-900 or 900-1000 MHz ranges. 2. Amateur use for reception of 902-928 MHz. band, downcon- verting to the 420-450 MHz range, 3. Reception of 902-928 MHz Amateur TV. using a standard TV receiver that covers UHF channels 20-23. and reception of wireless TV links operating In the 900-MHz range. 4. In conjunct ion with a 500- MHz counter* the measurement of frequencies in the 800^1000 MHz range. Referring to the block di- agram (Fig. 2). the converter uses a low-noise dual-gate P u Co g. ?^ m 43 GaAsFET [gallium-arsenide field-effect transistor) as an RF preamplifier Tliat feeds a dou- ble-tuned filter and a second RF amplifier using a MMIC. The MMIC feeds a second double- tuned filter. The overall RF gain is about + 27 to 30 dB and the bandwidth Is around 30 MHz. That provides good rejection of out-of-band signals and helps minimize the feedthrough of unwanted signals in the 400-500 MHz range. The RF amplifier feeds a double bal- anced mixer, or DBM, The DBM Is also fed with a local-oscillator signal of either 400-MHz (for 800-900 MHz conversion) or 500-MHz (for 900-1000 MHz conversion). The mixer output is therefore kept in the 400-500 MHz range covered by most scanners. The receiver should be suitable for the type of trans- mission to be received* A scan- ner is generally set to receive narrowband frequency modula- tion (NBFM) signals commonly used in this range in steps of 12,5 kHz. 25 kHz. etc, A TV re- ceiver tuned to the lower UHF channels ( 14—23) can be used to receive TV signals in the 900- MHz range, such as amateur TV (ATV) and the new 900-MHz wireless video links. Converter output is at 50-75 ohms. The local oscillator (LO) is a 50-MHz crystal-based overtone oscillator The second harmonic of the oscillator circuit (at 100 MHz] is used, A fine-tuning con- trol is provided to compensate for any 800-1000 MHz signals not fitting the popular 12,5-kHz channel spacing used by many scanners. The LO can be shifted at least ±6 kHz to act as a fine- tuning controL if needed. Nor- mally, the fine tuning is left set to center position. The 100-MHz oscillator signal is fed to a multiplier stage using a UHF large-signal transistor as a quadrupler (x4) or a quln- tupler ( X 5) stage. The appropri- ate harmonic (4th or 5th) is selected by a triple tuned filter and the signal at 400 or 500 MHz is delivered to the mixer. The filter can select either signal depending on the setting of three variable capacitors, A di- ode detector samples the output TABLE 1^800 TO 100-MHz CONVERTEft SPECIFICATION Freq Range RF Input IF OLTtOUt 400-500 MHz 800-900 or 900-1000 MH2 LO Fneq 400 or 500 MHz, internally selectable Noise RguiB <2dB typical Sensitivity gives 0.15 ^ly12dBSINAD, 5 kHz deviation with typical scanner Power Gain, RF to IF UN — ono ibut - ^ftn mh7 Rg = Rl = 50 n + 22 dB typical RF Bandwidth 40 MHz (a 3dB typical (a 900 MHz Maximirm Input Level -40 dbm @ 1dB compression Tuning Range 800-1000 MHz Dynamic Range AppfOK 90 dB (0.1 ^c to 3000 jav) Voltage and Current + 15-25 VDC {fi 100mA, Neg ground or 12-16 VAC (a 300 mA neak can be modified tor + 12 VDC regulated Fine Tuning Range ± 7 kHz typical PC Board (finished) size 3^^" X 5" X r high RF to IF Feedttirough Isolation (IN-OUT) DB >60dB{a 400 MHz Insertion Loss in dB with converter oft -1dB typical ca 400 MHz -0.3 dB typical^ 30 MHz Switching Built-in of the filter so that a VOM can be used to align the filter stmply by "peaking" the trimmer capaci- tors for maximum output. It is possible to Just use the 400-MHz signal However, for reception of 900-1000 MHz. a receiver capable of tuning 500-600 MHz would be needed. Most scanners cover only up to 512 MHz or thereabouts. There- fore, the 500-MHz signal is nec- essary with these scanners for reception of frequencies over 912 MHz. The converter board contains a switching network for switch- ing the converter in or out. In the "out" position, the input jack. JL simply connects to the output jack, J2, and all frequen- cies from DC to 550 MHz are passed. In this position, the DC line to the converter circuitry is also opened, thus disabling the converter The converter board also con- tains a rectifier and a regulator that delivers + 12 volts IX: to the converter circuitry. Either a + 14.5- to +24'Volt DC, or 12- volt AC supply can be used. Suitable supplies are either a wall transformer or one that mounts inside the converter case. Referring to Fig, 3, let's go over a detailed description of the circuit. Signals enter Jl from the antenna and are routed to SI, a DPDT switch with only one side used. With SI in the "ofT' position (converter off), signals from SI are routed to S2-a, another DPDT switch, (Slide switches SI and 82, al- though mounted at different lo- cations on the PC board, are mechanically linked by an actu- ator rod assembly so that cor- rect switching is maintained,) Next, signals are routed through S2-a to low-pass filter L16-C15, and then to J2. The low-pass filter rejects signals above 600 MHz. A 50-ohm im- PAFrrS LIST Ail resistors are ^A-watt, 5%* un- less otherwise noted. R1— 100,000 ohms. Va-watt R2— 470.000 ohms, '/s^watt R3— 180 ohms, Vfe-watt R4— 180 ohms R5— 390 ohms, Ve-watt R6— 1000 ohms R7— 10,000 ohms, trimmer potentt* ometer with sh^ R8— 10,000 ohms R9— 15,000 ohms RIO— 3900 ohms R11— 330 ohms R12— 100 ohms R1 3— 15,000 ohms R14— 2200 ohms R15^10 ohms, ^/e-watt R16 — 47 ohms R17— 1 megohm R18— 15 ohms, 'A-watt R19— 390 ohms. 1%-watt R20— lOohms Capacitors CI. C8. 09, 013. 014—1-5 pF trimmer C2-C7. C1CM:12, 016, 028, 031— 100 pR 50 volts, chip 015—5.6 pFNPO ±0.25 pF 017— 100 pF NP0,5% 018— 39 pF NFO. 5% 019— 22 pF NPO. 5% 020— 2.2 pF NPO, - 0.25 pF 021, 029—470 pF -^20%. disc 022, 030. 032. 035, C36— 0.01 50 volts, GMV disc' 023— 33 pFNPO ±5% 024— 56 pFNPO ±5% 025— C27— 2-^10 pF trimmer 033— 10 ^iF/16 volts, electrolytic 034— 470 M.F/25 volts, electrolytic Semiconductors 101— MAR-1 UHF amplifier 102— 7812 +12-volt regulator D1— MV2107 varactor diode D2— HP5082-2800 hot carrier diode 03— 1N4007 rectifier diode Q1— 25137 dual-gate GaAsFET Q2— 2N3563 VHF NPN transistor Q3— MPS3866 VHF NPN transistor L6D1— greeo light-emitting diode (optional) LED2— red light-emitting diode (optional) tnductors L1-L5, LI 0-^1 2— part of PC*lX)ard etching LB, L15— ferrite bead L7— 0.2-0.32 fiH (9Me turns #22 enameled wire) LS— 0.05^.1 fiH {3'^ turns #22 enameled wire) L9— O.05-0.1 (3V^ turns #22 enameled wire) L13— lO iiH RF choke LI 4 — ferrite bead on R20 LIS— Vt-tum #22 enameled wire, V* 'inch diameter (see text) Other components J1, J2— female BNO connector M0D1— MOL SBbiX mixer module SI. S2— OPDT PC-mount slide switch XTAL1— 50-MH2 3fd overtone crystal Mlsceilaneous: PC board, small- diameter 50-ohm coaxial cable, project case, 14.5-24-volt DO or 12'V0lt AC 350-mA transformer (see text), hardware as required, brass rod or wire, 2V4-inch mbber grommets, line cord if required, solder, etc. Note: The following items are available from North Country Radio, PO Box 53, Wykagyl Station, New Rochelte, NY 10804: • Converter kit including all parts except case and trans- former — $67,50 f $3.50 S&H • PC board only— $13.50 + $3.50 S&H • Transformer— $9.50 + $3.50 S&H New York State residents must add appropriate sales tax. pedance level is maintained through the converter In the "ofr position to reduce VSWR (voltage standing-wave re tic) and line losses » so that a scan- ner connected to J2 has normal reception when the converter is switched off. Switch S2 b breaks the t2-voU supply line in this position to disable the con- verter circuitry. In the converter "on" posi- tion, signals from Jl in the 800-1000 MHz range are fed througli SI to Li (an inductor that is incorporated in the PC board etching and acts as a short circuit to lower-frequency signals 1 and CI. which are reso- nant at 900 MHz. For matching purposes, at 900 MHz, 01 and LI must form a resonant circuit as weU as an impedance transformer to step up the 50-ohm impedance to somewhere between 800 and 1000 ohms. The input imped- ance of the gate of RF amplifier gi is about 1 to 2K or higher and shunted by about I pF ca- pacitance. The output imped- ance of Ql is between 1000 and 2000 ohms with 0,5-1 pF shunt capacitance. The voltage gain of Ql is about 7.5 from gate 1 to drain, or about 17.5 dB- There is about 1.5 dB loss in the output-coupling network and about 0,5 dB loss in LI, so that a total of about 15 dB gain is observed. The device is rated at 1,1 dB noise figure^ but allow- ing 1 dB (approximate) loss in LI and SI. an actual NF of about 2 dB will be obtained. That is adequate since cable losses in the tjpical antenna system will be around 6 dB an_>Vay. 'H-ansistor Ql is" a dual*gate gallium arsenide field effect transistor (GaAsFET) biased to about 5-10 mA drain current; R3 provides a self bias for QL Chip capacitors C4 and C5 are RF-bypass capacitors soldered directly to the solder side of the PC board for low inductance. They arc the only type of capaci- tor that provides reliable by- passing at 900 MHz. Resistors Rl and R2 bias gate 2 of Ql. The drain of Ql feeds double- tuned lilter C8-L2 and C9-L3, and R4 feeds bias to the drain of QL 'iy[>lcally the tuned circuits in this RF amplifier are tuned to 900 MHz with about 2.5 pF ca- pacitance, and L1-L5 have an equivalent inductance of 0,012 microhenrv^. although these val- ues are typical and cannot really be isolated or measured. Induc- tors L2 and L3 are printed on the PC board and are propor- tioned to give the desired coup- ling and inductance. Their layout is critical and cannot be changed. The signal from L3 is coupled through chip-capacitor CIO to ICL a monolithic microwave IC (MMICJ amplifier with 50-ohm input and outpuL Resistor R5 provides about 17 mA operating bias for ICL which gives about 13 to 15 dB gain at 900 MHz. The output of ICl is coupled via C12 to filter L4-C13 and LS-CH. The five tuned circuits in this I I 4 2 S 6 ■D m C TO LED1 (OPllOfJALi RG. 3— CONVERTER SCHEMATIC. A 50*ohm impedance level is maintained through the converter with SI in the "off" position so that a scanner connected to J2 still has noimai reception. Switch S2-b breaks the 12-vo1t supply line in this position to disable the converter circuitry. converter yield an overall RF bandwidth of 40 MHz at the 3 dB points. The signal from L5, about 28 to 30 dB stronger than the signal at Jl. is applied to a mixer module (MODI), an MCL SBL-IX, where it is mixed with the LO signal at 400-500 MHz. The IF output is then fed to S2- wiiere it is connected to J2 via low-pass filter L16-C15. An LO signal of either 400 or 500 MHz is required by mixer MODI. It is generated' as Ibl- iowsi Q2, a 2N3563. is config- ured as an overtone crystal oseillaton Emitter stabilization is provided by Rll, and R9-R10 provide base bias. Resistor R12 supplies Uie collector voltage fur g2 through L7 and L8. Compo- nents L7 and CIS are nominally tuned to 50 MHz. the frequency ofXTALl. Components C 19 and L8 form a resonant circuit at 100 MHz and therefore have a low impedance to 50- MHz sig- nals. Bypass capacitor C21 RF grounds the bottom (cold end) of L8. There exists a feedback ca- pacitance (about 3 pF) between the collector and emitter of 92. That, in conjunction with CI 7, forms an oscillator: the oscilla- tion of Q2 would tend to take place at the resonant frequency of C 18 (plus strays) and L7 (L7 Is variable by means of a ferriie slug). The base of 92 must t>e RF grounded^ which can only occur at the series- resonant fre- quency of XTALl. L13, and varactor-diode Dl: Dl acts as a capacitor whose value can be varied via the applied DC volt- age from potentiometer R7. Re- sistor R6 limits the lowest voltage to about 1 volt, and R8 provides RF Isolation for DL Varying R7 has the effect of var>''ing the effective frequency of the crystal plus and minus 1000 Hz. When L7 is nominally tuned to 50 MHz, the crystal os- cillator circuit produces a signal of 50.000 MHz. However, we need 100 MHz. Since Q2 operates as class-C and produces harmonics, filter L8-C19 is tuned to 100 MHz. That transfers 2nd harmonic energ>^ (6--i0 dB below the fun- damental 50 MHz) via coupling capacitor C20 to a second 100- NEXT MONTH IN Po pular Electronics MHz tuned circuit (C23, C24. and L9). Capacitors C23 and C24 are chosen so as to match the oscillator to the base of fre- quency multiplier Q3. an MPS3866, That generates har- monics of 100 MHz in the base circuit of 93. Capacitor C24 is chosen to have a low impedance at higher frequencies to encour- age the flow of harmonic cur- rents in the base circuit of Q3. Inductors LIO. Lll, and LI 2 form a filter tuned to either 400 or 500 MHz bv adjustment of C25. C26, and C27. There is sufriclcnt tuning range to cover either 400 or 500 MHz. The fil- ter Is triple- tuned and LIO. LI 1. LI 2, and their coupling coeffi* cients arc determined by the PC board layout which they are pari of. HF energy at 400 (or 500) MHz is taken from a lap on LI 2 and fed to mixer MODI, Without the right test equip- ment, it would be difficult to al- ign 025, C26andC27, However, the problem is solved by diode detector D2. C31. and R17. Re- sistor R17 slightly forward biases D2 to produce about + 0,2V at lest point TP2. When RF drive is applied from L12, a negative voltage is pro* duced at TP2. Wheri the triple- tuned filter is correctly tuned and Q3 is operating properly about - 0*3 volts is produced by D2, since about 300 millivolts of RF is present from L12, This, when added to the +0,2V bias on 1)2, produces -O.IV at TP2. Diode D2 is forward-biased lo improve its sensitivity at low RF levels. Tuning of C25, C26, and C27 simply consists of monitor- ing tlic DC voltage at TP2, and obtaining the most negative voltage possible bv peaking C25, C26. and C27." Regulator IC2, a 7812, pro- vides 12-volts DC power to the circuit; C32 and C33 and C34, 035 help stabilize IC2. Rectifier D3 acts as a protection device in case a negative DC voltage is ap- plied to the circuit, and C36 re- duces 60-Hz buzz caused by switching transients in D3. At least 14-volts DC is required across C34 for IC2 to function. Wlicn we continue next time, we'll build the converter and show you how to align it. R-E Exciting Features, Projects, Reports, & Columns • THE CLASSIC # BUILD A INDUCTION COIL SPEAKER PROTECTOR Make a spark ring and more when you experinient with this powerful high-vollage generator BUILD THE PRINTER SENTRY Use it to keep tabs on all of your printer's functions It saves your expensive loudspeak- ers from amplifier shorts, excessive drive, and tum-on thumps ELECTRONIC TRACKING FOILS CAR THIEVES Get the facts on the new high-tech crime-stopping systems Po pular ElectrMcs And there PRODUCT REVIEWS— Bang & Olufsen Compacl Music System. Memorex Subwoofer/Salellite Speaker System, and many more DX LISTENING— The changing face of Russian shortwave COMPUTER BITS— Low priced, high speed modems f IS morel THINK TANK — a potpourri of auto- motive circuits HAM RADIO — Design and build loaded-dipole antennas SCANNER SCENE— Monitoring movie-set communications CIRCUIT CIRCUS— Some un- usual uses (Of common regulator IC's PICK UP Pb pular Electronics AT YOUR FAVORITE NEWSSTAND, CONVENIENCE STORE, OR SUPERMARKET^ ft] a. 3 3 47 LEN FELDMAN WitI new standards bring of AM radio? AN TRIES FOR rr MAY COME AS SOMETHING OF A SURPRISE TO THOSE OF US who pay little attention to AM radio that this oldest of aU broadcast serv^ices is due for some up- grading. After all, the FM radio service has been the preferred form of radio broadcasting in this coun- tiy for at least two decades, nou^ and even FM radio may some day be obsoleted by digital audio broad- casting, or DAB. In fact» more than a dozen pro- posals for DAB are currently either on the drawing boards or have been demonstrated in prototypes. So why bother with AM radio at this late date? The AM stereo debacle Back in the mid- 1 980 the Federal Communica tions Commission considered several systems for AM stereo broadcasting. Many AM broadcasters felt then that the reason for the decline of AM radio audience was the fact that FM could offer stereo whereas AM could not. initially the FCC selected one of some six systems, the Magnavox proposal, as a "standard. " Faced wi th aH sorts of threats of 11 tiga- tion by other proponents, the FCC reversed itself shortly thereafter and in effect, said, '^let the mar- ketplace decide/' Since then, the field of propo- nents has narrowed down to two — the Motorola C- Quam system (by far the most popular) and the Kahn-Hazeltine system. Many experts maintain that by not coming down In favor of a specific sys- tem, the FCC has discouraged both manufacturers of receivers and AM radio broadcasters from mov- ing to stereo, With AM broadcasting audience on the decline for many years, manufacturers of high quality AM/ FM tuners and receivers have paid little attention to the AM circuitry^ that they incorporate in their prod- ucts. Figure 1 shows the actual frequencj* re- sponse measured for the AM section of a highly reputed AM/FM stereo receiver. No won- der listeners accustomed to playing digital compact discs and FM radios are "turned off by this kind of AM reception! This "after- thought" approach by receiver manufacturers further exacerbated the problem. Another problem of AM has been adjacent channel in- terference — a problem that Is particularly in- tense during evening listening. Many profes- sionals blame the FCC for that problem as well, maintaining that the granting of broad- cast licenses by the FCC has been a poorly administered "pork barrel * affair with httle back the good oV days A COMEBACK attenUon paid to the technical problems that have inevitably resulted from an overcrowding of the broadcast band. NRSC to tlie rescue! As the AM broadcasters situation became worse and worse, the National Association of Broad- casters (NAB) and the Electronic Industries Associ- • atlon (ElA) finally decided to address some of the problems in what amounted to a major cooperative effort between organizations that, up until that time, had pretty well ignored each other The two organizations formed a separate committee known • as the National Radio Systems Committee, or NRSC. In a series of meetings, the NRSC came up with two standards recommendations, known as NRSC-1 and NRSC-2. A proposal to make NRSC-1 a national voluntary standard was issued in Januarys 1990, and in March 1991, the EIA published the contents of NRSC-1 as an interim standard (ELA/ IS-80) entitled l\udio Bandwidth and Distortion • Recommendations for AM Broadcast Receivers/' On a parallel track, the PCC issued a report and order on April 27, 1989 In which compliance with NRSC-1 was made mandatory as of June 30, 1990» while measurement of compliance with NRSC-2 was postponed until June 30, 1994, Both NRSC-1 *and NRSC-2 were designed to address the problems of audio fidelity and Interference mentioned above, NKSC-1 and EIA/IS80 Let s take a look ac the EIA Standard developed for receiver manufacturers first^ Radio receivers that satisfy the technical requirements of this specifica' tlon must have a frequency response of not less than 50 Hz to 7500 Hz, with limits of + L5 dB and - 3.0 dB, referred to 0 dB at 400 Hz. Since "opening up" the bandwidth to this extent might well In- crease interference from adjacent channels— es- pecially in crowded metro- » poll tan areas and during night- time listening — receiver man- ufacturers may choose to offer a switch on their products that would, at the user*s option, re- duce bandwidth. As long as at least one of those switch posi- tions results in the frequency response just slated, the re- ceiver will be considered to com- ply with the new standard . The second part of the NRSC standard deals with harmonic distortion. It states that re* ce Ivors designed to satisfy the standard shall not exhibit more than two percent (2.0%} total harmonic distortion plus noise (THD + N) at all measured fre- quencies between 50 Hz and 7500 Hz. Two percent distortion may sound like a higli nunilier to those of us accustomed to tlie distortion levels of modern au- dio amplifiers and FM tuners, but. in fact, many current non- conforming AM tuners exhibit far higher distortion levels lhan thal!^ — particularly at higher au- dio frequencies. A third recommendation of the standard Involves the incor- poration ofcircuiti^' into AM re- ceivers that attenuates 10,0- kHx adjacent-channel carrier frequencies by 30 dB. or 20 dB when the measurements are madewithpreemphasis charac- teristics inserted at the AlVI in- put of the RF test signal generator To clarify that las I point, we should note that in recent times, recognizing that AM radios had very poor high- frequency response, broad- casters began boosting the au- dio treble response of their transmission chains in an at- tempt to overcome the high fre- quency attenuation present in nearly all AM radios and tuners. Unfortunately no two stations used the same boos! of pre- emphasis characteristic* FYir- t her mo re, an overly extreme use of high-frequency preemphasls made the problems of inter- ference between adjacent chan- nels even worse. So, included In the NRSC-1 recommendation is a fixed prccmphasis charac- teristic that AM radio broad- casters are required to use. The preemphasls characteristic, not unlike the one used by FM broadcasters in the tJ,S., is shown in Fig, 2, Assuming that broadcasters conform (and as of this writings well over half the AM broad- casters in the United Slates have embraced NRSC-1 stan- dards), manufacturers of AM ra- dios are expected to voluntarily incorporate standard, fixed TYPiaL FFlEaUEHCY RESPOWSC OF AH TUNER SECTIOH Of 'Him FIOaiTY' PE£ElVEfl 10. ODD 6.0000 S.DOOD 4.Q00O a. 0000 0.0 -2,000 -4.000 S.OOO B.OOO -10.00 flp \ * \ I / ?0 100 It lOfc 201; FIG, 1— AMPLITUDE VERSUS FREQUENCY, This J5 the response of the AM tuner section of a "hi-fi" AM FM stereo receiver! FIG, 2— BY STANDARDIZING THE PREEMPHASrS CHARACTERISTIC used by AM broadcasters, AM receiver manufacturers are able to incorporate standard deem- phasis networks in thetr products to achieve the desired flat response to 7J kHz or better. deemphasis networks. In mea- suring the frequeney response of an AM radio conforming to the new standards, a laboratory would expect lo obtain a fre- quency response sucii as that sho\\Ti by the dashed line in Fig. 3. The solid lines represent the allowable deviation or tolerance over the range from 50 Hz to 7.5 kHz. Results shown in Fig. 3 presuppose that the appropri- ate preemphasls network is In- stalled between the audio gener- ator and Ihc amplitude modula- tion input terminals of the I^F signal generator. If such a pre- emphasls network is not used in the test* results should be as shown in Fig. 4. RESPOUSE Of DeMOOUUTED OUTPUT FOfl SETS CONFORMING TO HRSC-1 ST*NO*RO ■10.00 '15.00 '».00 '25.00 ?0 100 Ik Ra 3— FREQUENCY RESPONSE of AM dfCuUry thai is required to conform to the NRSC-1 startdard. The dashed line represents an ideal response, with (he soHd lines representing the tolerance limits, (Presumes preemphasis In the RF test generator) f%£5P0f^E OF DEHOQULATEO OUTPUT FOR SETS MHEH NO MOOULJ^TION PftEEMPHASIS IS USED 5.0000 0.0 -5.000 ■10.00 -15.00 ■20.00 ■25.00 20 100 Ik lOt RG. 4--FREQUENCY RESPONSE of AM circuitry that is required to conform to NRSC-1, with no preemphasis in the RF test generator. RG. 5— AMAX LOGOS will identify AM radios that meet the NRSC requfrements. NRSC-2 by 1994 During the interir^ ppfiocl from Jnnp 1990 in Jvfw 1<194. the FCC is going to pre*iutT!P that if a station rnnfnrms to NRSC-U it is also in compliance with NRSC'2, The chief reason for the delay is the lack of appro- prlale* inexpensive test equip- ment needed to confirm com- pliance with all the provisions of NHSC-2. Those provisions man- dale that. NRSC-2 deals pri- marily with attenuation of carrier emissions rather than indirectly with audio response and performance. According to the NRSC-2 rules, emission*^ between 10.2 kHz and 20 kHz removed from the carriers fun- damental RF frequency must be attenuated at least 25 dB below the unmodulated carrier leveL Emissions between 20 kHz and 30 kHz away from the carrier frequency must be attenuated by at least 35 dB below the un- modiilalcd carrier IrvcL Emis* sions I hat are between 30 kHz and 60 kHz away from the car rler frequency must be atlenu- aled by at least 5 + IdB/kHz below the unmdodulated car- rier level. (For example, emis- sions that are 50 kHz away from the carrier frequency would have to be attenuated by 5 + 50. or 55 dB relative to the ievel of the unmodulated carrierl. Fi- nally emissions between 60 kHz and 75 kHz must be attenu- ated by at least 65 dR. More breathing room While the NRSC-1 and NRSC-2 provisions will cer- tainly help alleviate some r*f the problems of interference be- tween stations, it cannot do the whole job in view of the con* gestlon of the AM band t hat now exists in some geographical areas. Accordingly as of Jntv 1, 1991, the FCC nfficialtv ev- panded the AM band bv an addi tional 100 kHz, The band now extends from 535 kHz to 1705 kHz. This additional spectrum space is expected lo accommo- date at ieast 200 AM stations, nationally. Rather than increase the number of licenses tn broad casters, however, it is expected that those stations causing the mntTo Be A Partner In A Group That Has A Multi- Billion Dollar Surplus You Are. Ifyou'reoneof the 133 million working Americans and 6 million employe who con- tribute to Social Security each year, you' re already a partner in a ffoup ttith a multi-billion dollar surplus. Social Security designed to provide ev*er>^ irking member of society with a founda- tion for retirement. In addition, you get disability iasunmce and survivor benefits for your Eamily. It's a partnership you can rely on. Learn more about }vtir benefits. Write: Dept. 37, Pueblo, Colorado 81009. There's Sifdv friOurNuiiibeis most severe Interference will be asked to move up into the new frequencies- In order to retain their audiences, however, it is likely that those stations whose frequencies are reallocated to this new portion of the band will be allowed to "simulcast" on their existing frequencies for some time until a sufficient number of new AM radios are purchased by the listening pub- lic. Manufacturers (and par- ticularly makers of car audio systems) have already incorpo- rated the new swath of frequen* cies in their products and it turns out that the cost of doing so is minimal. A new symbol of escellence As tiiese attempts to improve AM transmission and reception were being formulated, the NAB and the EIA came up with the idea that It would be nice to have some visible means of Identification displayed on radi- os that meet the requirements of the new standards. After nearly two years of agonizing over the design of a symbol, the organizations have come up with a decal to be called the "AMAX" symbol* which stands for "AM Radio at Its maximum potential/* The certification logo could be affixed to radios that meet basic eligibility crite- ria including the equalization standards, variable bandwidth and other requirements de- scribed earlier TWo types of logos will be available. The sec- ond one. reading "AMAX Ster- eo." will be applied to improved AM radios that also have stereo capability Ulustratlons of both logos appear in Fig. 5. The "AMAX" program does not mandate a particular stereo AM format — only that the radio be capable of receiving and de- coding some kind of AM stereo transmission. Of course, the decision to market AMAX cer- tified radios is at the discretion of individual manufacturers* as is the decision to apply the "AMAX" or "AMAX Stereo" logo to the sets themselves. Inter- estingly, we recently learned that the latest Delco/Bose car audio radios, as installed in some 1992 model General Motors automobiles, do in fact meet the AMAX criteria but for reasons of aesthetics, the car maker elected not to apply the logo to the radios, at least for the present. The NAB plans to publicize the logo through its member stations, who will be encour- aged to develop promotional tie- iris with local audio retailers. NAB is also expected to unveil a major campaign by the time you read this, promoting enhanced AM radio to consumers. In addi- tion to the improvements that we have already mentioned, eli- gibility of a radio to bear the AMAX s>Tnbol must also include provision for an external anten- na, noise blanking for pulse- type interference and the ex- panded AM band. Will improremcDts help? While both the EIA and the NAB are enthusiastic about these attempts to improve AM, the question that remains Is whether or not AM can attract enough of an audience to re- main a major broadcasting for- mat in the years ahead. Even though it is still uncertain whether or not the improve- ments in AM broadcasting and reception will attract new lis- teners to the band, the many improvements are certain to be welcomed with open arms by those who have been listening to AM for quite some time. While many AM broadcasters speak of a "level playing field" (against FM). the fact Is that even with response extending to 7,5 kHz. sound quality cannot compare with the quality of FM, to which so many listeners have become accustomed. Still, when you hear an AM broadcast that has extended frequency response of this kind. Its amazing how good it does sound when compared with the "typical" AM radio sound we have endured for many years. Perhaps AM radio can be given a new lease on life — even if it*s only a temporary reprieve until digital audio broadasting [which some now prefer to call digital audio radio, or DAR) re- places both of our current modes of radio. M LAST MONTH ^VK INTRODUCED YOU to our professfonal-quallly 2,5- MHz function generator and fre- quency counter that can read up to 150 MHz, This month well shovi\vou how to build, test, and properly use this essential test Instrument, SWEEP/FUNCTION GENERATOR cultry is mounted on three PC boards; the mother board/ daughter board, and LED dis- play board. The PC boards are available from the source men- tioned in the parts list. Foil pal- terns are provided here if yon wish to make your own boards however the artwork was de- signed for nonplated holes. In nlaces where if ifi imDOssible i the board to the other If you do make your own board. you1l have to solder some wires from the top of the switch arrays to points on the board. That is not necessary if you use the boards supplied with the kit. Figures 6 and 7 show internal photographs of the authors prototype. Solder all diodes and resistors first, followed by the capacitors and then the ICs. IC sockets are not required, but they may make life a lot easier i n the event of trouble. It*s best to build and test func- tional blocks as you go rather than building the whole unit all at once. First, start by con- structing all the cable assem- blies as indicted in Fig. 8. Start with the power-supply section, and verify that the output volt- ages are correct. The AC power cord routes through a strain re- lief in the back planet* and one side Is soldered to the top of switch S15 (pole a). The other AC lead is soldered to the pad connected to fuse FL Next, build the triangle and square-wave generator sec- tions. Those sections consist of components with the IXX and 2XX component numbering scheme. A parts placement di- agram of those sections* located on the main board, is shown in Fig. 9. You will need an os* cilloscope to v^erify that a tri- angle wave of about two volts peak-to-peak is present at the gate of Q5* and a one- volt peak- to-peak square wave Is present at the collector of 96. If those two waveforms are not present » go back and check your solder joints and component orienta- tions. Potentiometers R125 and R126 set the symmetry of the waveform and should be ad- justed to give a triangle wave with equal slopes. R129 sets the upper frequency limit and should be adjusted to give your desired high frequency for a given range. That is done with the course frequency-adjust po- tentiometer SlOl in its max- j imum position. As a general ^ guide, set R129 for a maximum J frequency of 2.5 MHz* with the 1-MHz range switch engaged. g Potentiometer R223 sets the zero balance of the triangle wave g. and is adjusted to give a cen* ? tered signal. Square-wave bal- S ance is achieved through poten- g tlometers R224 and R225. You | can now check the pulse output ^ for TTL levels and a variable CMOS level. With I he basic gen- 53 I • "^^^ *• 5 • • * ■ ■ ' " ^.hI - m IWCHES - COMPONENT SIDE DAUGHTER BOARD foil pattern. 4H INCHES COPPER TAB COimCTS OH BOTTOM CASE mB)UEM;¥ RAWGE SWTTCHES FIG. 6 — INSIDE VIEW OF the author's prototype. A transparent red acrylic sheet was usad for the front panel. A copper tab is soldered to the ground pfane of the daughter tjoard and contacts a by 3V^inch conduclivre shield, which Is glued to the inside of the bottom case (not shownji USE SHIELDED LEADS F0BJ1-J^ SOLDER SIDE DAUGHTER BOARD foil pattern. R325/ M2^f oiofi/ nl.; ^^3°' S301 ^ S401 S102 ™V seoi S101 S201 SBD2 FIG, 7— INTERNAL PHOTO OF the author's prototype. Start construction by con- necting all cable assemblies to switch-potentiometers mounted on the front paneL erator now functioning, build the sine-shaper circuit (compo- nent numbers 3XX1 and verify a sine wave at the output of IC9, Adjust R323 for a two- volt pealc-to-peak sine- wave output at ICQ pin 12. The amplitude of the square wave is controlled by R324. which should be set to give a clean square wave with- out any overshoot or rounding on the edges. The output amplifier should be built next. That section uses the 4XX numbering scheme. Set to R423 to its center posi- tion and adjust it only if there is no output. Next, put your os- cilloscope on DC coupling and observe the DC level of the out- put, adjust R422 until the out- put waveform is centered around zero. Verify the open-cir- cuit signal swing of 20 volts peak-to-peak and the "20-dB attenuator switch. The last work on the mother board is to build the frequency- counting section and to mount the display board. The six dis- play LED's are soldered to the display board, which is con- nected to the motherboard by a 90-degree, 14-pin strip header With the display and compo- nents in place* observ^e the dis- play Select the MHz range and make sure that all the digits are functioning. If not, go back and double check the circuit. Use a frequency counter or scope to calibrate the counter by adjust- ing C504 so that the display reading is the correct frequency selected. The daughter board, which holds the counter input ampli- fier and sweep generator is as- <4 stoi I o o o FREOUEHCY ADJUST t J <4 SI 02 Duwcvae _ 3zr_ J13 SWEEP TIME <4 <4 <4 RS30 I J J6 TTL — O* — p QM03 S201 L£va i_, — ! J7 @J1 CABL£ ASSEMIUES J14 <4 B83I iSWfEP I WIDTH 1 I — o o VCF INPUT ^J4 JT5 » » » » J16 POWER t » » RG. 8 — CABLE ASSEMBLIES show the potentiameters that are connected to each of the function switches. sembled next. That parts* placement diagram is shown in Fig. 10. The frequency-counter Input circuit must be tested with an extemai signal or by se* lecting the external-signal source function and jumping the generator output to the counter input. Ifesting consists of verifying the operation of Oie switches, SI 1-814 and the in- put amplifier The input amplifier can be tested by var^ln^j the amplitude of an input signal from about 25 millivolts to 50 volts peak-to- peak tif no test signal is avail- able» use the generator itself) and observing the frequency reading on the display The fre- quency should remain the same for all amplitude conditions. When selecting the prescale function, the display should shift two decimal places to the right if working correctly All the boards were designed to use transistors with an emit- 1 1 t 1 "20dBArT£MUArOR t 1 R325 )J2 L _j J3 I . EXTOTIAL 'FBEQUfHCY COUNTER INPUT ter-collec tor-base pin arrange- ment, and the rectangular pads are configured to accept that. If you choose to use the alternate transistors indicated in the parts list, they are American made* and use an emitter-base- collector pin arrangement. When the substitutes are used» a small circular pad is placed between the emitter and collec- tor of the rectangular pads. This circular pad is used for the base pin and the collectors and emit- ters remain connected to the rectangular pads. I ho a. 59 PARTS UST All msistors are Vi-watt 5% un« less otherwise indicated. Riot— 2700 ohms, 1% R102. R104. R105. R109, R111— 100.000 ohms, 1% R106— 33.200 ohms. 1% R107, R108, R11 0—1000 ohms, 1% R112. R114— 3010 ohms. 1% R1 13-^9,900 ohms, 1% Rt15, R1 20— 4990 ohms, 1% R116. R121— 7150 ohms. 1% R117, R122— 348 ohms, 1% R118. R123— 75,000 ohms. 1% R119, R124— 750,000 ohms, 1% R125, R126. R826, R827— 10,000 ohms, potentiometer R127. Rt28 — 5000 ohms, potenti- ometer (part of S101 and S102, respectively) RT29, R825— 20.000 ohms, potentiometer R201, R210, R220— 10,000 ohms R202, R222-^70 ohms R203— 390 ohms R204. R206, R219-1000 ohms R205, R216, R217— 2700 ohms, 1% R207. R20&-4020 ohms, 1% R209— 511 ohms R21 1^0,000 ohms R212— 2000 ohms R213, R214— 13.000 ohms R215— 910 ohms. 1% R218 — 7500 ohms R221— 47 ohms R223. R828— 5000 Ohms, potentiometer R224, R225, R228, R229^2000 ohms, potentiometer R226— 10,000 ohms, potentiome- ter (part of S201) R227 — 4700 ohms, potenliometer R301^ag00 ohms, 1% R302, R3D3— 11.300 ohms. 1% R304, R306—12J0O ohms, 1% R305— 309 ohms, 1% R307— 200 ohms. 1% R308, R309— 24,900 Ohms. 1% R31 0—127 ohms. 1% R31 1—63.4 ohms. 1% R312. R313. R320— lOOO ohms R314— SlOOohms R31 5^-680 ohms R316— 150 ohms R317— 6800 ohms R318. R3t9— 10.500 Ohms. 1% R321— 2000 ohms R322— 12ohms R323, R324— 1000 ohms, potentiometer R325— 5000 ohms, potentiometer (partof S301) R401, R402, R503. R504-'1 0,000 ohms R403, R404— 22,000 ohms R405— 170 ohms, 1% R406— 12,000 Ohms R407— 1200 ohms R408— 2000 R409— 18,200 ohms 1% R41 0—270 Ohms, 1% R411— 100 ohms, 1% R412, R414. R502— 3000 ohms R41 3— 24,3000 ohms, 1% R415, R418-^7 ohms. 1W R416, R417— 7,5 ohms R419— 50 ohms. R420— 499 Ohms. ^/^W R421— 56.2 ohms. 1% R422. R424— 10.000 Ohms, poten- tiometer (R424 is part of S401) R423— 200 ohms, potentiometer R501— 100,000 R505 — 10 megohms R701— 10,000 ohms R702— 100.000 Ohms R703— 1 megohm R704— 50 ohms R705, R7ia-"150 ohms R706. R712— 220 ohms R707— 470 ohms R708, R715— 51 Ohms R709-R711, R713, R714, R716. R717— 510 ohms R719— 36 Ohms R720— 1000 ohms R801— 7500 ohms, 1% R802— 33.000 ohms. 1% R803— 33 ohms, 1% R804, R805, R807— 5100 ohms, 1% R806. R810, R816, R817, R819, R820, R822— 10.000 ohms, 1% R808— 510,000 ohms, 1% R80^2200 ohms, 1% R811— 22,000 ohms. 1% R812— 2400 ohms, 1% R8ia-100ohms, 1% R815— 150,000 ohms. 1% R81 8— 15,500 ohms, 1% R821— 2000 ohms, 1% R823— 15.000 ohms. 1% R824— 18.000 ohms. 1% R830. R831— 5000 ohms, potenti- ometer (part of S801 and S802. respectivety) Capacitors C101. CI 02, C204, C205— 0.1 (^ramrc C103, C203— 100 pF, ceramic C104— 0.001 p.F. Mylar C105— 0.01 |jlF, Mylar C106— 0.1 Mylar C107— 1 fiF, Mylar C108. C504— 15-60 pF, variable capacitor C201— 68 pF, ceramic C202— 0,047 ^F, ceramic C301, C30a— 0,1 M-F, ceramic C302, C304, C502— 39 pF, ceramic C305, C401^,7 pF. ceramic C307— 15 pR ceramic C308, C408— 5^ pF, variable capacitor C402— 120 pF, ceramic C403— 2.2 pR ceramic C404. C406— 6.8 ^R tantalum, 20 volts C405. C407— 0.047 [if, ceramic C501— 33 pR ceramic 0503^10 pF, ceramic C601. C602— 1000 \lE electrolytic, 50 volts C603, C604 — 100 {lH electrolytic, 50 volts C605— 1 fiR tantalum. 20 volts C701, C704-C706— 0.1 ^R ceramic C702, C707— 100 pR ceramic C703 lOu tantalum 16 volts C801— 22 fiR tantalum, 16 volts C802, C803 — 220 pR ceramic CS04. C805— 100 pR ceramic C806— 500 pR ceramic Semiconductors D101-D108. D201-D204, 0206-0226. 0301-0312, D315-D318, 0401. 0402, 0701, 0702, 0801— 1N4148 diode D205— 1N751, 5,1-volt Zener diode D313. D314-1N746, 3.3-volt Zener diode BR1— W02M bridge diode Q1, 04, 012, 013. 021— 2SC1815 or MPSA05 NPN transistor 02. Q3, 06, 07, Q11, 019, 020— 2SA1015 or 2N4403 PNP transistor Q5. Q17— 2N4416, N-channel FET 08— 2N3904, NPN transistor 09, 010, 014— 2SC1923 or MPSH34. NPN transistor Q15— 2N2219. NPN transistor Q16— 2N2905, PNP transistor Q18— PN5139. PNP transistor ICl, IC2— LM741, op-amp IC3, 1C4— LM308, op-amp ICS. IC6, IC20— GA3086. NPN transistor IC (Hanis) 1C7— 7420. dual 4-inpu1 and gate 1C8 — 4011, quad hand gate 1C9 — CA3030, op*amp ICl 0—4066. CMOS quad bilateral switch IC11 — 7216B, frequency counter and LEO driver (Intersil) IC12— 7815, + 15-volt voltage regulator IC13— 7805, +5-volt voltage regulator IC14— 7915, -15-volt voltage regulator IC15— MC10116, ECL triple-line re- ceiver with Schmitt trigger (Motorola) IC16— SP8629, prescaJer (Plessy) (C17— LM324, quad op-amp ICia— MC1458, dual op-amp 1C19— OA3140, op-amp (Harris) SR601—1000 ohms, thermistor DISPt-DJSP6— common-cathode LED (FND357) Other components 4PDT-D switch S8— DPDT switch DPDT-D switch S12-S14— DPDT-l switch S15— DPDT on/off switch 5101— DTDP switch used with R127 (5K potentiometer) 5102— DTDP switch used with R128 (5K potentiometer) S201— SPOT switch used with R226 (10K potentiometer) S30t— DPDT switch used with R325 (5K potentiometer) S401— SPOT switch used with R424 (10K potentiometer) 5801— DPDT switch used with R830 (5K potentiometer) 5802— DPDT switch used with RS31 (5K potentiometer) J1-J4 — BNC connector J5. J14— e-position femaie/male, 0.1 -inch centers J6— 5-positlon female/male. 0.1- inch centers J7, J12— 2-position female/male J8, J13 — 6-position female/male J9^J11, J16, J16— 4-positton female/male, 0.1 -inch centers XTALt— 10-MHz AT/CUT crystal T1— 115/40 volts AC, 0.5 -amp transformer F1— 0.5-amp fuse MisceHafieous:Gase (CTP-1 by Global Specialties), three 1,75- inch standoffs, four S-inch stand- offs, two TO-5 heatsinks, ihree TO-220 heatsinks, three PC boards, internal wiring, fuseholder, 3-conductor 18- gauge power*suppiy cord, and strain iBlief, Note: The following items are available from Trfstat Elec- tronics, inc., 66A Brockington Ores., Kepean, Ontario, Cana- da, K2G 5L1, (613) 22S-7223: • A set of tiiree etched and drilleci PC boards— $76. • All components without the PC board and case — $250. 0 Complete kit of all parts (un- finished front panel)— $300. • Cut and siik-screened front panel— $10. Add $17 for shipping and han- dling. Send check or money order only. COMPONENT SIDE FOIL pattern of the mother board. The sweep generator is built next. If youVe using the boards supplied with the kit, mount potentiometers R825-R828 to the solder side of the board. That will make adjustments easier when the unit is as- sembled. If you re making your own boards, place the potenti- ometers on the component side and make your adjustments be- fore the board is connected to the mother board. Once again you 11 need an os- cilloscope to verify proper align- ment. Set R828 to its midpoint, FIG, 9— THE DUAL-PRIMARY TRANSFORMER can accommodate 115-voJt operation by connecting the two primaries in series: 1 to 3 and 2 to 4. For 220-voit operation, connect pins 2 and 3 in series. Also, the transistors have an extra base pad for diHerent packages. dtPi D^pi OfS^ OtSI'^ and adjust R825 to give a good log output [when selected) and a linear output. Adjust R826 to achieve a good input signal to IC19 pin 2 and R827 will set the maximum sweep width. If a scope Is not available* most po- tentiometers can be set to their R80? 62 Ra 10— MRTS PIJtfSEIIEflTOF DAIfQHTEfl BCIARD hotds tlie input amplifter and sweep generator circuit center position and adjust- ments can be made by observ^- Ing the LED display with the counter set to the internal- count mode. If everything is working prop- erly you can Install the com- pleted boards Into the case. The top of the case uses four 2-inch standoffs. The front and back panels supplied with the case are of 0,065-inch aluminum and are not recommended for use as a front panel. A complete cut and silk-screcned panel is available from the source men- tioned in the parts list, or you can make your own using trans- parent red acryilc. Secure the motherboard in place (top half of case) and finally install the daughter board uses three Wa- inch standoffs. You*re now ready to power up and use your combination function gener- ator and frequency counter Using your imit T^ble 1 shows a complete list TABLE 1— FUNCTION GENERATOR SPECfFiCATIONS FUNCTION MIN MAX UNJTS n 1 Triangle Wave 04 2.5 Mega Hz Square Wave 0.1 2.5 Mega Hz Pulse 0.1 2,5 Mega Hz Ampitude Msin Output 3.0 20 Vp-p 20dB 05 6 Vp-P TTL Pufse 1 50 5 Vp CMOS Pulse 0.5 15 i Vp Duly Cycle 10 90 % Ukj KjUSBI — 10 + 10 VUU ! Sweep Width 1 1000 X Initial Freq. Sweep Time 1 20 Seconds Frequency Counter Input Sensitivity 20 100 Vp-p Input Range 0.1 150 Mega Hz Input Impedance 50 1 Mega Ohms Gates Trmes .01 10 Seconds Error ±LSD Stability 50ppm/°C of functions and specificatioiis oftheuniL The square wave output is in phase with the sine wave and the triangle wave* but is 180 de- grees out phase with the TTL and CMOS pulse outputs. That feature is useful for creating a twa*phase clocking system if you happen to be working with digital equipment. The unit is calibrated to give a frequency range of 0.1 Mz to 2.5 MHz. The upper frequency limit can be ex- tended by adjusting variable ca- pacitor CI 08 andVor R129. With the component values that we have given » the upper frequency^ limit can reach as high as 4 MHz, Changing the values of the timing resistors Rl 15-R119 and R12Q-R124 will produce output frequencies as determined by the formula 1/RC, That method will achieve a maximum sine- wave output of 10 MHz with an amplitude of 1 volt pcak-to-peak above 2 MHz. r-e GET THE LATEST ADVANCES IN ELECTRONICS WITH A SUBSCRIPTION TO tiBEirDniES. jfKOltlEtCaSTEa. ttUCHUIT ENJOY THE WORLD OF ELECTRONICS EACH MONTH! ® Now you can subscribe to the best electronics magazine. The only one that brings you articles on— electronics projects, technology, circuit design, communications, new products and much more. Radio-Electronics looks to Ihe future and shows you what new video, audio and computer products ore on the horizon. What's more you'll find helpful, monthly deportments such as Video News, Equipment Reports, Hardware Hacker, Audio Update Drawing Board. Communications Corner. All designed fo give you instruc- tion, tips, and fun. R tid I £]-EI(»c Ironies gtves you o kg I ting artlcldsllke: J ISDN Th6 T&tephDne Nuiwork of Ttimofiow J Tho Facts on FAX J A Qtpjtal Phone Lock J Hjjw To De^rgn Sw^icfiing Circuits J ElA-^32 A real standard lor serial inlerlacing^ J Butid a syneigy card *of your PC J W Pdwef al a ?m price J BuHid 4 bioleeffiiack mqaitor J More 0" MuTliiJlejting FOR FASTER SERVICE CALL TODAY 1-800-9997139 SUBSCRIBE TODAY Just fill out the order card in this magazine and moi! it in today. Co un t e r survei 1 1 ance S! S I I 111 6 64 Never befom has so much professional information on the art of detecting and eliminating electronic snooping devices — and how to defend against experienced Information thieves— been placed In one VHS video. If you are a Fortune 500 CEO, an executive in any hi-tech industry, or a novice seeking entry into an honorable, rewarding field of work in countersurveillance, you must view this video presentation again and again. U'f/jlr uff! You may Ix^ the vtcrim of stolen words — pruxious ideas thac would luvc madtf yoo wry wcalrhy! Ytrs. firatVs- sionals, evx-n rank amart-urs, may be lis* U'oin^ to yoor most private con* Vi-rsarions. ViUke up* if you are not the victim, then you are surrounded by countless vic- tims who need your help if you know how f (J discover telephone taps, U>cafe bu^js, or "sweep" a mom clean. There \^ a thriving professional service sreeped in high-tech techniques that you can become a part otl But hrst, you must koow^ and understand Counrersur\'eilance Technology. Ybuf very* first instj*ht into this highly teuiirding held is made possi- ble by a video VHS prcsentation that you cannot view on bn*adcast releviston* sat- clltte» or cable. 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J' Sif;njiiirt _ Njmc Aikirt** _ A3I ftifmcnti ir S A fy(vb Otudtim #^4 Si ptf 4JJ jpi^lifnblt u|c^ T4K. llie professional diKussions seen on the TV scR-en in your home reveals how* to detect and disable wiretaps, midget radto-frecjuency transmitters, and other bugs* plus when to use disinformatitm to confuse the un^^-anted listener, and the technique of voice scrambling telephone communications. In face, do you know how to look for a bug, whea^ to look for a bug, and what to do when yx)u find it? Bugs o* a ver^' small sire arc easy to build and they can be placed quickly in a matter of seconds, in any object nmm. Today you may have used a tele[>hofte handset that was bugged. It probably contained three bugs. One was a phony bug to ffessionat can sweep a rm\m so that he can detect voice*acti- vated {VOX) and remote -activated bugs. Some of this equipment can be operated by novices » others require a tiained coun- eersurveillance profess ionaL The professionals viewed on your tele- vision screen rcv^eal information on the latest technological advances like laser- beam sn(K>pers char are installed hun- dreds of feet away from rhe room they snotjp on. The professionals disclose that computers yield information too easily. Tliis advertisement Wiis not written by a cou n tcrs u rvei 1 1 a nee p rofess io na 1 , b u t by a beginner whose only experience came from viewing the video tafxr in the pri- vacy {/his home. After you review the video carefully and understand its con- tents, yt>u have taken the first important step m either acquiring professional help with jiour sun-eillancc problems, or yau may very^ well consider a career as a coun- tersun'eil lance professional. The Dollars You Save To obtain the information contained in the videtJ VHS cassette, you would attend a professional seminar costing $3"^ 0-750 and possibly pay hundreds of dollars more if you had to travel to a distant city to attend, Now^ for only Si 9. 9 5 (plus S4.tK> P&H) you can view^ CQuniersur- feillmict Techniques at home and take refresher views often. To obtain your copy, complete the coupon below or call toll free. EXPERIMENTING WITH ADC FOR YOUR PC JAMES J. BARBARELLO PC -BASED TEST INSTRUMENTATION has turned out to be a popular topic among readers. We con- tinue this ongoing series by in- terfacing new sensing devices (a linear displacement transducer, a piezoelectric transducer, and a microphone] to the analog- to- digital converter (ADCl dis- cussed in the January 1992 is- sue, Ifyou'rejust getting started with this series, here's a brief review of progress thus fan Quick review The heart of the system is a PC I/O expander called the PC lO that adds 24 lines of digital 170 by means of an 8255 Parallel In- putyOutput (HO), all on a single 8-bit expansion card. In the January 1992 installment* we added an outboard analog-to- digital converter (ADC), based on an ADC0804. The ADC al- lows you to measure and cap- ture any Q-5 volt analog signal (e.g., temperature* displace- ment, and audio). The circuit includes a variable-gain ampli- fier for low-level inputs, and a DC-offset adjustment for inputs with unwanted DC compo- nents, A temperature probe Add a variety of analog inputs to the PC-based analog-to-digital converter. shown in that article was built around the base-collector junc- tion of a silicon transistor. With the proper settings for ampli- fication and DC offset, a several- hundred millivolt change over a lOO^'reeC temperature range produced a digital output spread over the full input range of the ADC0804. In general an A/D converter and a PC can provide very low- cost solutions to measurement problems that would ordinarily require costly test equipment. Following are some ideas, prac- tical circuits, and software for interfacing other types of de- vices. These ideas cover the three most common types of sensing: mechanical* electrical, and acoustic. Mechanical sensing As an example of mechanical sensing, the author and a friend were contracted to mea- sure the displacement, impact force, and velocity of elec- tromechanical rappers used in the pollution-control Industry, Factory smokestacks have en- vironmental controls that con- tain huge, electrostatically charged metal plates. As the smoke goes up the smokestack, it passes by those plates; the plates "pull" the suspended par- ticles to them, removing pollu- tion that would otherwise be released to the outside air. Parti- cles accumulate on the plates, and eventually have to be re- moved. To "clean" the plates, rappers (like giant solenoids) provide quick, hard jolts to the plates, breaking trapped parti- cles free in huge sheets that fall to the bottom of the smoke- stack. Our task was to deter- mine the characteristics of existing commercial rappers, and then determine whether our customer's rapper could be made better than the competi- tions. Our test instrumentation consisted of an 8-bit A/D con- verter hooked up to a computer, and fed by a rectilinear potenti- I I fu 9- 9 m 65 RG. 3— INTERFACE AN AUDIO SOURCE as shown here. The nonsequential part numbers occur to keep numbering consistent wrth the original circuit. FIG. 4^RAPHICAL OUTPUT from GRAFDATA.BAS (Listing 2>, which allows you to display as many as 1000 data points captured by ADC.6AS (Listing t). I >-+sv IKjr— [02 Aumm LINEAR AT} COfMRTpR , DiSPLftCEWEMT UAH 1992 FIS^ pPOTfMTlOMETER RG. I^NTERFACE A LINEAR displace* ment transducer to the PC 10 as shown here. The wiper of the LDT drives the APC0304 directly, so remember to dis- connect the op-amp output (pin 7) from the ADC's input. (The original circuit was shown In Rg. 2 in the January 1992 in- stallment) PfEZO '/fPHONt TRANSDUCER PLUG FIG. 2— INTERFACE A PIEZOELECTRIC transducer as shown here. Make sure the red lead goes to the tip and the black lead to itte ring of the plug. Also, to avoid feeding DC voitage into the transducer, disconnect the J1 end of R1. ometcr (also called a linear dis- placement transducer, or LDT), LDTs are precision potentiome- ters that move linearly, rather than circularly. Even at surplus prices, LDTs aren't cheap (S20-S50K but they do a great job. Figure 2 in the January 1992 issue shows the complete ADC circuit; we simply suppl led it with the input shown here in Fig. L Note that we power the LDT directly with a 5-volt DC supply so neither amplification nor DC offset were required. In- stead, we drive the ADC0804 (1C2) directly, as shown in the figure. If you use this type of arrange- ment, be sure to disconnect the op-amps output [pin 7) from the ADC's input (pin 6). In addi- tion, make sure the potent lome* ter has a resistance of at least IK, so as not to draw too much current from your PCs power supply Also, the mechanical linkaj^e between the LDT and the rapper must be firm so there is little or no slippage at the speeds encountered. Other- wise, the potentiometer will not give a true indication of dis- placement. This type of setup would also be useful for measur- ing the movement of solenoids, pistons, cams, and similar de- vices. Using that circuit, we ob- tained a series of outputs that showed exactly how the rappers plunger moved a quarter of a second after it triggered. Eight bits of digital data made it easy to calculate the rate of change of displacement (velocity), as well as the maximum displacement. We determined impact force using strain gages. The only problem we had was in determining just when to read the LDTs resist a iice. The solution turned out to be straightforward, as we'll see momentarily Electrical sensing The temperature probe de- veloped last time is one example of electrical sensing. Another good sensing device is piezo- electric material, available in both film and cry^stal form. An inexpensive source of piezo* electric cry^stal is Radio Shacks Piezo Transducer (273-073). Simply break open the plastic case, and you have a circular piezoelectric transducer with red and black leads* When fiex- ed in any way, the transducer produces a voltage that varies proportionally to the amount of fiexing. A piezo transducer can be used to measure force of Im- pact, or the amount of bending and flexing. Figure 2 shows how to connect a piezo transducer to USTING 1 1 REM***"** * 2 KEM»» AI3C.BAS - V?10a03 * tjj Barbarftllo * 5 REM** Capture/ Store Analog Data with PcA/D*MATE ' 4 REM**" 10 CIS : DBPm A, X: DIM AdOOOJ : GOSUB 370: LOCATE 1, 23 20 mim -PCA/D DATA COLLECTIOei SVSTEH': LOCATE 2, 1: PRIHT STR1«G5(79. 220) 30 LOCATE 5, 1: PRIHT SPACES <79i,- : LOCATE 5. 10 40 LIKE iflFirr "Ent^r Tlia& [0-3600 secQods} betveen s^a^les* . . *f intervals 50 interval = VALtintervalSJ 60 IF interval < 0 OR interval > 3600 THEW BEEP; GOTO 3D 70 LOCATE 7. 1<^: PRINT •Press to begin, or <£sc> to abort . , , * ; BO GOSUB 350: IF AS ^ CHRS(27J THEN CLOSE : END 90 LOCATE 5, 10: PRIOT SPACES C 60 J: LOCATE 7, 10: PRINT SPACES t60 J 100 LOCATE 10, 22: PRII^T 'DIGITAL DATA l0-2S5)j*; LOCATE 12, 19 llO ir intei-^al > 0 mm PRIHT "SECOJIDS SETWEHJ SAMPLES: ir.terval 12C LOCATE 13* 25: FF.INT -SAMPLE tWMBER; " 130 LOCATE IS, 20i PRINT 'Press to End Sampling,,,-? 140 acount « 1: Ksan^Ie ^ I 150 told a VAL(MIDS< TIMES, 4, 2M * 60 4 VAU RIGHTS (TIMES . 2)) 160 IF intcirval ^ 0 TUm GOTO 210 170 T = VAL mi D$ (TIMES, 4, 2jj ' 60 * VAL t RIGHTS (TIMES , 2)) 180 IF T » D AJID (told - T > interval) then told = told * 3fiO0 190 IF IIIKEYS ft CHR$(27J THEN GOTO 260 200 IF T ' told > 0 THEM told = told + iilteryal ELSE GOTO 170 210 OUT ADD +2.0: OUT ADD ^ 2, 1 220 X = INPiADD): LOCATE 10, 44 i PRlMT USI^SG *###■; x 230 LOCATE 13, 44: PRINT xsample; i jcBample = scsample + 1 240 IF acount < 1001 THEN A(acounc} xj acount = acouat + 1 250 IF IWKEYS <> CHSS(2'Ji THUl GOTO 160 260 BEEP: LOCATE 16. IS 270 PRINT •press for no save,,.'; 290 GOSUB 350; IF ASCiASt = 27 THEN CLE : QID 290 LOCATE 16, 15 3O0 LINE INPUT •Enter File Nanie To Save Data (ex: TESTOl- ADD) . , , • ; fS 310 0PE2^ -r*, I, f$, 2; FIELD 1, 2 AS dl5 320 LOCATE IB, 20: PRINT •Saving Data,,,'; 330 FOR i « 1 TO acount: LSET dl$ s KKlS^Ati) J: PTJT 1, tOF(l> / 2 * 1: KEXT 340 PRINT -Done. Press AMY key,-; : A5 = INPUTS (IJ: CLOSE : CLS : eiD 350 AS = IKKEYS: IF AS = '• THEN GOTO 350 360 IF ASC(AS> = 13 OR ASCIAS) = 27 THEN RETURN ELSE BEEPt GOTO 350 370 OPm 'R** 1, •HKABDRES.OAT', 4: FIELD 1, 4 AS AS 380 GET 1, It ADD = VALtASJ : CLOSE : DEF SEG ^ 64; OtTT ADD ♦ 3* 146: P-ETURH 1 REM** GRAFDiATA.aAS 2 REM*' Graph PcA/D-Kate ,AOD File Data (Requires Graphics Monitor) 3 REM*' V910802 - JJ Barbarello 4 REM*' 10 CLEAR : DEFINT I- J, Y: KEY OFF: CLS 20 COLOR 0, 7: LOCATE 3. 27: PRINT • GRAPH PcA/D-MATE DATA 'j i COLOR 7, 0 30 LOCATE 10. 20: lUPOT "Enter File Name (ex: TESTl .ADD) . , . * ; DFJJS 40 OPE« "R*. 1, DFI>IS, 2: FIELD 1, 2 AS D$; IF L0F{1) > 0 THEN GOTO 80 50 CLOSE : KILL DFKS : BEEP: LOCATE 25, 13 60 PRitiT "That File Doesrs ' t exist. Press ANY key to try again,,-"? 70 AS = INPUTS(l): CLS : GOTO 20 80 LOCATE 21, 34: COLOR 16, 7; PRINT " Reading data *j J COLOR 7, 0 90 DIM lULOF(l) / 21 + 3 J ICO FOR I = I TO LOFdJ / 2: GET I, I: I (I) = 390 - CVIIDS): NEXT 110 LOCATE 21, 34: PRINT SPACES (20) 120 LOCATE 12, 20: PRINT 'File Han't LOF(l) / 2; 'Safl^tsles,' 130 LOCATE 14, 20: INPUT •Enter Start Sanple To view..**; ISTART 140 LOCATE 15. 20: INPUT 'Enter End Sample To View"; IFIN 150 IF IFIN - ISTART > 1000 THEN IFIN = ISTART ^ 999 160 I(I) = 1(1 - 1): III ♦ 1) = Id); in ^ 2} = 1(1 + II 170 YINC « 5O0 / aFIH - ISTAKT) 180 IF tlFlN - ISTARTJ > 499 THEN istp = 2 ELSE istp = 1 190 SCREEN 2; LOCATE 2, I: PRINT 'SAMPLES"; LOCATE 3, 1; PRlffT • 200 LOCATE 4i 1; PRUH' 'Start:*; ISTART: LOCATE 5, 3: PRINT "Eiid:*; iriN 210 LOCATE 20, 1: PRINT 'Press *s LOCATE 21, 3: PRINT "To End,..- 220 I.XNE M3B, 0)-(I3S, 190): LIME (138, 190}- (619, 190}: J - 139 230 FOR I s 0 TO 152 STEP 38: LINE 1126, I)-(237, IJi ME5CT 240 LOCATE 1, 13; PRINT 'S.O*; LOCATE 24, 16: PRINT "0"? 2 SO LOCATE 12, 12: PRINT •VOLTS'; 260 FOR I « ISTART TO IFItJ STEP istp 270 LIKE (J, I (I)) -(J * YINC, 1(1 + istp) ) ; J = J * YINC: NE)£T I 260 AS = IN}tEY$; IF AS = " THEN 200 290 IF ASC(AS) = 27 THE^I SCREEN Or END ELSE BEHP: OOTO 280 our circuiL We want only the of Rl, shown in Fig, 2 last time voltage generated by the ptezo (HI provided +5-volts DC to the sensor, so disconnect the Jl end temperature probe). With no In- put signal, adjust Rll for max- imum gain, and R12 so output is about 2,5-volts DC, (The lat- ter setting allows the piezo volt- age to vary from that quiescent leveL) You might also want to adjust the value of R3 so that the piezo sensor produces max- imum indication at its max- imum output. To test the circuit, use a piece of masking tape to secure the piezo sensor to a flat surface, making sure you aren't flexing It. Tkp the surface firmly and note the response. In actual use, you would mount the sen- sor using a clamping device or flexible adhesive. This type of device is useful for measuring applied impact, oscillation after Impact, or amount of flex or bend. Acoustic sensing You've probably seen audio signals displayed on an os- cilloscope. Now Imagine "freez- ing" those signals — l,e., storing them in digital form. Scientists capture digitized audio in this way to study the sounds that whales, birds, and other ani- mals make. In digitized form, its easy to compare and con- trast different sounds to deter- mine which have similar characteristics, or to look at other factors that wouldn't oth- erwise be obvious. To accommodate a micro- phone input, we modlBed the ADC circuit as shown in Fig, 3. The changes allow us to in- crease the gain of ICl-a to a maximum oflOO, and to attenu- ate high-level inputs. Gain is de- termined by the ratio R14/ R6 - 10^/10 * = 102 = 100. If the part numbering in Fig, 3 seems strange. It s because we tried to stay consistent with the main j circuit shown in Fig, 2 in Janu- |" ary. Note that in the January ^ version, R6 was lOOK; her^ we ^ decreased its value to lOK, Also, ^ we no longer use Rl— R4, ^ In operation, first set R12 to £ mid-value. Then adjust R14 for 9 maximum range, as described ^ last time. Last, readjust R12 as § necessary to set the quiescent level to about 2,5-volts DC, For ^ example, a microphone might provide a maximum output 67 LISTING 2 1 REM** GRAFDATA,BAS 2 REM** Graph FcA/D-Hate *ADD File DdCa (Requires Graphics Monitor) 3 REM** V9l0e02 - JJ Qarb^rellO 4 REM** 10 CLEAR : DEFINT I- J, Yt KEY OFF: CLS 20 COLOR 0, 7: LOCATE 3, 27; PRim* • GRAPH PcA/D*MATE DATA : COLOR 1. 0 30 LOCATE 10, 20: INPUT 'Ent^r File Mame lex: TESTl ,ADD| . , . - ; DFN$ 40 OPEK -R-, U DFKS, 2: FIELD 1. 2 AS D^; IF LOFtU > 0 THEN GOTO 80 SO CLOSE : JCIU, DFKS: BEEP: LOCATE 25, 13 60 PKXm "Tliat File Doesn't exist. Press AKY key co cry again*..-; 70 AS 3= n^P0T5tl) : CLS ; GOTO 20 BO LOCATE 21. 34: COLOR 16, 7: PRDfT ' Reading data ; COLOft 7. 0 BO DIM I((LOFU) / 2) * 3) 100 FOR I m 1 TO LOFtl^ / 2; GET 1 . I r 1 (1) = 190 - CVUDSH llEXT 110 LOCATE 21. 34: PRINT SPACES (20) 120 LOCATE 12. 20: PRIHT "File Has'; LOFtl) / 2; 'S^spleB,' 130 LOCATE 14, 20: IHfUT 'Enter Start Saiaple To View,.."; tSTART 140 LOCATE 15, 20: INPOT 'Enter End Sample TO View*,- IFIH 150 IF IFIN - ISTAHT > 1000 THEK IFIH = ISTA3KT * 999 160 KIJ * I{I ' 111 Id + = HI} I Id * 2) = Id * 1) 170 YIMC * 500 / CIFIN - ISTARTI 180 IF UFIM - ISTART) > 499 THS^I ISTP = 2 ELSE ISTP * 1 190 SCREDi 2: LOCATE 2* Is PRIHT -SAMPLES*: LOCATE 3, 1: PRIHT 200 LOCATE 4. 1; PRIHT "Start;-; ISTART: LOCATE 5* 3: PRINT 'Bodt*; IFIH 210 IjOCATS 20, 1: PRINT *Preas - ; LOCATE 21. 3: PRINT 'TO 220 LIKE (138* 0)-ll38, 190): LINE (138, 190)* (639, 190): J ^ 139 230 FOR I « 0 TO 152 STEP 38: LIJIE tl28, I) - (137, IJ : NEXT 240 UX:aTE 1. 13: PRINT 'S-O*: LOCATE 24, 16: PRINT 'O*! 250 LOCATE 12, 12: PRINT -VOLTS*; 2€0 FOR I « ISTART TO IFH^ STEP ISTP 270 LIKE IdJj-tJ ♦ VINC, 1(1 * ISTP}); J s J * YIMC: HEXT I 280 AS = IWKEYS; IF AS = " THIK 280 290 IF ASCtAS) = 27 THEH SCREEN 0? END ELSE BEEP: GCfTQ 280 voltage of 0.5. Adjust R14 so the maximum is about 4.0 volts. Then readjust R12 so the no-sig- nal (quiescent) value fs about 2.5-volts DC. Now you'll get the best resolution from the circuit. Software We wrote two programs for data capture and display. List- ing 1 shows the capture pro- gram (ADC.BAS). and Listing 2 the display program ( GRAF- DATA. BASl— both are available on the I^E-BBS 1516-293-3000, 1200/2400. 8N1) as a file called PCADMAT2.LST. Figure 4 shows sample output from GRAFDATA. Enhanced ver- sions of both programs are available on disk from the au- ^ thor for a nominal fee; see the ^ sidebar for details. I* ADC. B AS IS a general-pur- 5 pose data capture and storage ij utiiitj: To use it, you must create g a data file called HWAD- E DRES.DAT in the same directo- 5 ry as the program. The file con- ^ tains the decimal address of the 6 PC lO card. You can create the "S file with any text editor or word ^ processor capable of storing text in ASCII format. Assuming 68 your card is sat to the default address (640], create a one-line file that contains "640D" (with- out the quotes) followed by a carriage return. Connect the ADC circuit to your PC and run ADC.BAS. It initializes the PC 10 card, then asks you for the interval (in sec- onds) to wait between samples. If you want continuous samples (with no delayK enter 0. Other- wise, you can enter any number between 1 and 3600 (one hour). When you press Enter, sam- pling begins. The program displays three pieces of information: current data (line 100). time between samples (line 110). and current sample number (line 120). Press Esc at any time to end sampling (line 130). Lines 150—200 take care of in- terval timing. The sampling program showed last time used a timing loop that was system- dependent: the current version reads the system clock, hence is system- independent* Sampling takes place in lines 210—250: as many as 1000 samples are saved in array A. When you press Esc to end sampling* execution continues at line 270. If you press Esc ?10K TRIGGER OUTPUT _? RG. 5— DIGITAL TRiGGER CIRCUIT al- lows the PC 10 to start reading data based on the appearance of a pmdeter- mined signaL Connect this circuit be- tween that signal and an unused PC 10 input, and modrfy ttie software accord- ingly. ORDERING IKF0RMAT1ON The following items are avajlable from JJ Sarbarello, 817 Tennent Road, Manalapan, NJ 07726. • Complete PC 10 Board with PC board and all components (p3rt# PCIO)— S39.95 • An APC0d04 and a calibrated PN222A temperature sensor tran- sistor (part #ADC)— $8.00 • PC 10 software, including com- piled and source code versions with continuous and interval sam- pling and data logging/listing. Specify disk size. 3.5'' or 5.25". (part #ADC-S)— W 00- • Software from this instalment, Including a menu-driven, compiled program (with source code), ex- panding on the identified functions and adding discrete data listing, graphed data sample selection/ value display, and other features (pari #ADM-S)— $10 Specify part number(s) and send check or Money Order The author will be glad to answer any questions, but they must be ac- companied by a self-addressed stamped return envelope. again, data is abandoned and the pragram ends. If you press Enter, the program requests a file name for storing the data. Specify the complete file name, including any path and extension (e.g., C:\SUB1\TEST01. ADD.) If you don*t specify a complete path, the file \^ill be stored in the current directory, if the file alread>^ exists, current data will be appended to the end of the file. GRAFDATA. OAS allows you to plot your data on-screen. When you run the program, it asks you to specihr a data file. As with ADC.BAS, specify' the full file path if the file is not in the cur- (Continued on page 76) o- ^P) RIGGER INPUT WORKING WITH lED'S We continue our survey of optoelectronic principles and systems, with an in-depth ^ look at practical LED chaser \ and bar-graph displays*^ RAY MARSTON i LAST MONTH. WE BEGAN INTl?ODUC- Ing the general subject of op- toelectronics, and we examined Ifght-emittlng diodes (LED's) and several practical LED flash- ers In detalL In this article, well examine several practical LED chaser (or sequencer), dot. and bar-graph displays. ilafXI Chaser prmciplce One of the most populafl^ED displays is known as a chaser, also called a sequencer Thatls when an IC drives an LED array, so that each LED (or small groups thcreoO turns on and off in a fixed, periodic sequence, that appears as a ripple of light running along a chain. The LEDs don't necessarily have to be arranged linearly and can be placed in any desired geometric pattern, to alter the visual effect. The most popular CMOS IC which is used for that purpose is the CD4017B. which is a de- cade counter/divider IC with 10 decoded outputs , each capable of directly driving an LED dis- play If desired, the outputs can be coupled back to the IC con- trol terminals to make the de- vice count to (or divide by) any number from 2-9, and either stop or recycle. The CD4017B is easily cas- caded for use in multi-decade frequency division, or for use in counters with any number of decoded outputs. It's extremely versatile, and it can easily be used in a chaser or sequencer LED display of any desired length. Figure 1 shows the pinouts of a CD4017B. with decoded out- puts in arithmetic order. Figure 2 is its timing diagram; the CD4017B is a 5-stage Johnson counter with ci^ocKt reset, and CLOCK INHIBIT tnputs. The coun- ters are advanced with each positive-going clock pulse, when the clock inhibit and RESET inputs are low. At any time, nine of the 10 decoded outputs are low while the re- maining one is high. The 10 outputs go high se- quentially in step with the clock » with the selected output + 3-15V ..t -V Jl IC1 'T "4" •5" CLOCK ■7" INHIBIT R£SET "r a CARRY OUT 10 DCCOOfD > DECIMAl OUTPUTS n 12 FIG, 1— PINOLTTS OF THE CD4017B do- cade counter divider, with its decoded outputs shown In ascending arithmetic order. The clock is inh lb jted by a high on pin 13, and the counter Is reset by a high on pfn 15 and advances on a positive* going clock transition. \ Staying high for one full clock cycle. The carry out goes high for one clock cycle out of every 10 clock cycies, and it can be used to ripple-count more CD4017BS in a multi-decade counting application. The counting cycle is inhibited by setting CLOCK inhibit high. A high on the reset input clears the counter and sets the "0*- output high. CD4017B chaser circuits Figure 3 shows a practical CD4017B 10-LED chaser, with ICl, a 555 as table multi vibrator which is used as a variable- speed clock generator. The CD4017B becomes a decade counter by grounding pins 13 [clock iNHiBiT) and 15 (reset). The visual display will appear as a moving dot sweeping from left to right (or from LEDs "0*-' 9" ) in 10 steps, as the outputs go high and turn the LED's on se- quentially They can either be arranged in a straight line, or configured circularly so that the dot appears to rotate, The LEDs shown in Fig, 3 aren't current-limited. Man- ufacturers don't give a max- imum short-circuit current for the CD4017B, but practical ex- perience dictates a value some- where between 10-15 milli- amps. The maximum dissipa- tion per output on some data sheets is 100 milliwatts, so up to 7 volts DC can be developed safely across a CD4017B output stage at maximum current. Each LED is connected be- tween output and ground, and can have a maximum supply of 9 volts DC, for a 2-volt DC drop across each LED thatla lit. Above 9 volts DC, use the version shown in Fig, 4, which contains a current-limiting resistor, and is capable of being used with supplies up to 12 volts DC, Figure 5 shows a possible equivalent of the circuit In Fig. 4, that uses a 15-volt DC supply, that also illustrates a major de- sign flaw. Wlien one LED Is on, the anodes of the others are grounded, so Rl reverse-biases them. Due to low LED reverse- voltage ratings, youll often find that an LED thats off will act like a Zener diode at about 5 aocK INPUT ■r I i I I *4- I CARRY I OlfT n n n — i i n 1 n n n 1 n 1— n 1 M 1 ■ 1 1 — H— r~L j 1 1 1 1 r 1 n 1 — 1 - * t 1 n i 1 1 t ! — 1 — 1 n — 1 n 1 — n u n 1 1 FIG- 2— WAVEFORM TlMfNG DIAGRAM OF THE CD4017B. with Its reset and clock iMHiBiT terminals (pfns 13 and tS) grounded* 1^ CI C2 LIT LtDZ UED3 LED^ LE 0©©© RESET aOCK RG. 3^A 10-LED CHASER OR SEQU ENCER that can be used with supply voltages up to only 9 volts DC, and which produces a "moving-dof' display. RG. tO-LED CHASER, WHfCH USES up to a 12-volt DC supply RG. S— A POSSIBLE EQUIVALENT to Rg. 4» which uses up to a 15* volt-DC supply. voits DC, and possibly destroy- ing a CD4017B output stage. When a CD4017B drives LED's in moving-dot mode* they can be connected directly to the IC outputs if supply values are no more than 9 volts DC. For higher supplies* youll need cur- rent-limiting resistors. Several such display circuits are shown in Figs. 6-12. Alternative LED displays The output stages of the CD4017B can either source or sink currents equally well. Fig 6 shows 1C2 used in sink-mode In a moving-hole LED display: nine of the 10 LEDs are on at any given time, while one turns off sequentially If the LEDs are arranged circularly, they seem to rotate. Since all LEDs except one arc on at a lime, they all need current-limiting resistors. Moving-dot displays are much more popular than the moving*hole variety The type shown in Fig. 3 can be designed to use fewer LED s just by omit- ting the unwanted ones, but then the dot moves intermit- tently or scans, since 1C2 takes 10 clock steps per sequence, and all the LED s will be off dur- ing the unwanted steps. If a continuously-moving dis- play with fewer than 10 LED's is needed, connect the first un- used CD4017B output to pin 15 (reset), as indicated in the 4- LED version shown in Fig. 1\ To achieve an intermittent display using a controlled number of off steps, just connect the desired unwanted output to pin 15 ( rkset). Or* in other words, move the connection going to pin 10 oriC2 10 pin 9. In that type of an intermillent display, the LED's will light for four cycles, go blank for four cycles, and the sequence then repeals. Figure 8 shows a visually at- tractive 4-LED, 5-step se- quencer Initially all four LED's are on. and then turn off se- quentially until they're all off in the fifth step, as shovm in the accompanying table. The LEDs are effectively in series, and the basic circuit can't drive over four LEDs, Figure 9 shows another ver- sion; here, the CD4017B does a 10-step sequence* with LED 1 on from steps "O'-'a, " LED 2 on for "4^ - 6. ■ LED 3 on for V" and "8," and LED 4 on for step "9," The display will accelerate from LED 1-LED 4, not just sweeping smoothly from one LED to the next, and the cycle then repeats ad infinitum. Figure 10 shows such a cir- cuit modified to produce an in- termittent display where the visual acceleration occurs for 10 clock cycles, the LED's ail blank for 20 cycles, and then the counting cycle repeats. When IC2 is in a ^ 10 mode as shown in Figs. 9 and 10» pin 12 (cai^ry out) produces an output each time IC2 does a decade count, which is used to clock IC3 (which is connected in ^ 3 mode), with its "0 * output fed to For the first 10 cycles of a se- quence, the "0" output of 1C3 is high, and Ql is biased on, so 1C2 acts as shown in Fig. 9. with the LED*s turning on sequen- tially through 9 L After the 10th clock pulse, the "0" output of IC3 goes low. turning Ql off: the LED's can no longer UghL but 1C2 keeps counting. After the 30th clock pulse, the "0" output of IC3 again goes high and turns Ql on, reenabling the dis- play Figure 11 is a simple multi- plexed display where IC3 and Q3 enable or disable a bank of LEDs. Figure 11 is yet another example of a multiplexed dis- play whicli uses three lines of six intermittently- sequenced LED*s, TheyVc each sequen- tially enabled via IC3 and indi- vidual gating transistors, only 1.5K * 7 B2 m R3 1D0K n CI 1t»F 5 555 14 lEDl + 9V 16 RESET CLOCK CD4017B CLOCK INHIBIT "0' "1 .3.. "4- LfD2 (D 15 \3 ID LED3 C2 RG^ 7— A 4-LED CONTINUOUS "MOVING-DOT" DISPLAY. To get an intermtttent "mov- ing^of' dtsptay using a 50% "blanking" period, just change pin 10 (or output ''4") to pin 9 (or output ^B"), one line at a time; if you wanl» you can expand this version still further to control a 10-line» 1 OG- LED » matrLx display. Figure 12 shows a 4-bank. 5- step» 20-LED chaser: the four LED*s are in series in each of the five CD4017B outputs, so four LEDs are lit at any one lime. Each lit LED drops about 2 volts I m 1JK -CI R2 R3 6 100K IC1 55S 14 C2 lQ9;lW414S IC3 CD4irfTB ^0" 2H3W lis RESET CL0CKl|3 INHBfTTl C2 RG. 10— A 4-LED IKTERMnTENT ■ACCELERATOR'* DISPLAY, where the ' accelera- tion" occurs forlO out of every 30 clock steps. +9V 6 I I til 72 m S Vdd CARRY Oin 14 CLOCK 102 REsrr IG1 3 'V aocK rWHBIT -5- V,, CD LED2 / / LED7 0 // LED3 ti. IP r ^ & ^ ^ ^ ^ 10 a IE06 12 14 IS 13 IS aocK RESET IC3 aocK CD401TB iimerr "0" "1" "3" ^ss Q1 R4 12K R5 12K 15 13 m m 03 C2 1(M)m^ FTG. 11— A MULTIPLEXED 6-L£Ox3*UNE MOVING*DOT DISPLAY, \f\ wllich the dot moves intermittently along the lines. DC: thats 8 volts DC for each LED bank that's on, so the sup- ply voltage must be greater than that for the circuit to work. A greater number of LED s can be used in each LED bank if the supply voltage is correspon- dingly increased to handle the added load. Bar-graph displays Another multi-LED indicator circuit is the analog version, which drives a chain of linearly- spaced LED's, The number of LED s that are lit is proportional to the voltage applied to the LED-driven so the circuit acts like an analog voltmeter. You can be usefully cascaded to drive up to 10 LEDs in bar- graph mode only the members being the U237B, U247B. U257B. and U267B. The LM3914 family is more complex and versatile by comparison, and are easily cascaded to drive up to 100 LEDs in either bar- graph or dot-graph mode. Both varieties of IC's are considered to be bar-graph drivers. FIG. 12—A 4-BLAN K 5-STEP 20-LED CHASER, for USB with a supply above 9 volts DC. TABLE 1—U2X7B INTERNAL TRANSISTOR STATES AT VARIOUS INPUT VOLTAGES 01 02 03 04 05 1.0 OH Off Off Off Off 0.8 Oft Off Off Off On 0.6 Off Off Off On On 0.4 Off Off On On On 0.2 Off On On On On 0.0 On On On On On IC-driven bar-graph displays are inexpensive » superior alter- natives to analog meters. They don't stick, they're fast, and they're unaffected by both vibration and attitude. Their scales can have any desired shape* they can have mixed LED colors to highlight special sections, and they can be equipped with over-range detec- tors that are activated by the drivers to either sound an alarm, flash the display, or both. The linearity of such a bar- or dot-graph meter is considerably better than that of most analog meters, and is generally about 0,5%, The resolution depends on the number of LED s that are used: a lO-LED version has ade- quate resolution for most hob- byist puqioses. Basics of the U2X7B IC family The AEG U2X7B IC family is composed of four different 8-pln DIP'S, each capable of driving five LEO'S. The U237B and U247B pair produce a linear display and are used together when driving 10 LEDs. The U257B and U267B pair produce a logarithmic display and are also used together when driving 10 LEDs. All four IC's in the fam- ily use the same internal circuit- ry, in block diagram form, as shown in Fig, 13, All four IC's contain five Schmitt voltage comparators with unique thresholds feeding TABLE 2— U237B INTERNAL STEP VOLTAGES Device Step 1 Step 2 Step 3 Step 4 Step 5 U237B 200 mV 400 mV 600 mV 800 mV 1.00 V U247B 100 mV 300 mV 500 mV 700 mV 900 mV U257B 0.18V/ -15 dBW 0.53V/ -6 dBW 0,84V/ -1.5 dBW 1.19V/ + 1.5 dBW 2.0V/ + 6 dBW U267B 0.1V/ -20 dBW 0.32V/ -10 dBW 0.71V/ -3 dBW LOV/ 0 dBW 1.41V/ + 3 dBW TABLE 3— U237 IC FAMILY MAJOR SPECIRCATIONS Parameter Mini- mum Typ- ical Man- mum Supply voltage 8V 12V 25V Input voltage 5V input cument — — 0,5 mA Max supply current — 25 mA 30 mA Power dissipation (at 60°C) — — 690 mW Step tolerance -30 mV 30 mV Step hysteresis 5 mV 10 mV Input resistance 100 K Output saturation voltage IV into transistor switches. The thresholds are fixed by the tap- ping points on voltage divider Rl— R6, which is powered using a built-in voltage regulator: each comparator input is con- nected to pin 7, All four ICs also contain an internal 20-milliamp constant- current source, and the five ex- ternal LED's go in series be- tween It and ground (pin 1), as shown. Groups of LED's are turned on or off using the indi- vidual switching transistors. If Q3 is turned on. it sinks 20 mU- liamps via LED's 1 and 2, so they turn on. and LED s 3—5 turn off. The U2X7B family has step voltages spaced at 200-millivolt DC intervals, and Tkble 1 lists the states of Its five internal transistors at various input voltages. At 0 volts DC input, all five transistors are switched on. so gi sinks the full 20 milli- amps. and all five LED's are off. At 200 millivolts DC, Ql turns off but all other transistors are on. so Q2 sinks the 20 milli- amps via LED 1, driving LED 1 on and turning all others off. ^•1 3 JR2 V. r LED1 B 01 :R3 1— t - '5TIJ1 I 1^5 BASIC IMTtRfJALS AND GOWJECTtONSOf UUm ICfAMILY FIG. 13^BL0CK DIAGRAM OF a U2X7B bar-graph driver showing the basic ex- ternal connecttons. .,0. + o (0-1V) ICT UZ37B i ^1 P5> 0. LE01 LED3 ) \ LED5 FIG. 14— A 0-1-VOLT DC, 5-LED, linear- scale bar-graph meter ysing a U237B. With an input of 1 volt DC, all transistors arc off, the 20 milli- amps go to ground via the LED*s, so all five LEDs are on. The IC current is independent of the number of LEDs turned on, so minimal RF interference (RFI) is produced as it switches transistors and LED s. The four lC*s in the U2X7B family differ only with regard to their step voltages, which arc fixed by R1-R6 as showTi in 1^- ble 2. and the values for which are also given in dBW (or dB rel- ative lo a watt). The Hnear-scale U237B and U247B pair of ICs can be used lo make a lO-LED, 1-volt DC linear meter The log- arUhmic-scale U257B and U267B pair of IC's can be used to make a 10- LED logarithmic meter with a full-scale value of 2.0 volts DC. or +6 dBW. The reason for the correspon- dence between those two values is justified as follows. Since where P is power E is v^oltage, and R is resistance, then the as- sumption, for purposes of con- venience, is that: R^l ohm. If so, then to convert voltages on the logarithinic-scale meter into a quantity proportional Lo power (and not into power it- sein. just square the voltage in- dicated, take the log^^ of the result, and multipfy by 10. If E has the unit of volts (as opposed to some fractional or multiple unit, like millivolts, for exam- FIG. 15— A 0-1-VOLT DC. 10-LED, linear- scale bar-graph meter using a U237B and a U247B connected as a pair m 150K m 10K dm 2700 I tlfJO IC1 UZ37B FIG. 16— METHOD OF REDUCING the sensitivity of the bar-graph meter shown in Fig, 14, tor use in a 0-15-vo1t DC, 5- LED, linear-scale, bar-graph meter using a U237B. + 12-25V(REGUUTO)1J R1 10K R2 100K (SET FOR SPECIFIC OEVICEI R3 1-lflK TRANSDUCER ICI GffD 6 LBD1 5 tED2 I* 4 IH)3 2 LED5> RG. 17— SIMPLE USE OF A transducer to show the value of a physical quantity. pie), then P has the units of watts, and the units in dB are called dBV. since they're ex- pressed relative to a fixed value of potential. Likewise, if you wanted to ex- press dB In terms of power, then the proper terminology would be dBW, or a similar unit for any fractional unit of power. The number of dBV is always double the number of dBW, since tak- ing the logjQ of both sides of the power relation gives log(P)-Iog(E2/RK ^2>ctog(E) + iog(flK = 2xlog(E) + log(1), -2x(og(E). For that reason, 1 dBW = 2 dBV. For example, in Table 2, for the U267B and step 5, the entry given is 1,41 volts DC, or -h3 dBW. On squaring that, you get Which symbol represents a variable inductor? 2 volts^, so 10 times its logio is + 3 clBW, and doubling that gives +6 dBW. Of course, wiien ever you take the logarithm of a quantity like voltage or power, you always operate on the nu- mcrieal part alone » and ignore tlie units. If you ever hear of an audio or noise level that's ex- pressed in dB aIone> with no unit appended to indicate "dB with comparison to what/* such a specification is nonsense. To express an amplitude in dB relative to a unit of potential or power with a multi-letter abbre- viation, just append the whole unit, like dBmV for dB relative to a millivolt. Sometimes, the term dBm is used as an abbre- viation for dBmW. or dB relative to a milliwatt, T^ble 3 lists the specifications of the U2X7B family When driv- ing live red LED s, each with a 2- volt DC forward drop, the mini- mum supply value required must be 12 voits DC. Different- colored LEDs with different for- ward drops can be used to- gether if the supply voltage is adequate. Although the IC input imped- ance is typically lOOK, the IC be- comes unstable if the source impedance is above 20K. It should ideally be kept under lOK: if it's not. place a 0.01-ixF capacitor between pins 1 and 7 for added stability. Practical U2X7B circuits Figures 14—19 show practical U2X7B-famiiy circuits; in all of tliem» the supply is 12-25 volts R2 2.7K . Dl S.8V 47K (SET FOR:^*. SPECIFIC^ DEVICE) R3 , 1-10K- THAftlSDUCEB 1C1 6MD 6 5 I 3 LED4 2 LED5 FIG, 18— AN ALTERNATIVE USE of a transducer to show the value of a phys- ical quantity. Dl 1B4148 R1 2K R2 56K 4-Cl .56 56K: ICI UZB70 5 LEOI LED2 LED3 LED4 i£D5 (+3dBW> FIG, 19— A 5*LED LOG-SCALE audio- level meter; a 10*LED version is made using a U2S7B and U267B pair, in a fasli- lon similar to the version shown in Fig. 15. DC, but youH have to remember the constraints previously men- tioned. Fi^fure 14 shows a 0—1- volt DC. 5-LED, linear-scale meter using a U2X7B, and Fig. 15 shows a U237B and U247B pair used in a 0-1-volt DC. ID- LED, linear-scale meter. The lat- ter circuit operates each tC as shown in Fig. 14. with supply voltages that are appropriate to five LEDs, but their input ter- minals are tied together and the LEDs are alternated, to achieve a 10- LED display. Figure 16 shows how the full- scale sensitivity of the meter is reduced by feeding the input to ICl via R1-R2-R3. using a ratio of 15: K and giving full-scale sensitivity of 15 volts DC. Fig- ures 17 and 18 show how the circuit shown In Fig. 14 can be used to display a physical quan- tity like light intensity or heat, as represented by the analog re- sistance R3 of a transducer. In both, the transducer is fed by a constant-current source, so the input voltage to ICl is directly proportional to the transducer resistance. As shown in Fig. 17, constant transducer current is derived from regulaled supply via Rl- R2, since regulated supply volt- age is large relative to the 1-volt DC full-scale meter sensitivity. By contrast, as shown in Fig. 18, constant current is ensured viaDl-gi. Finally Fig. 19 shows the U267B used in a 5-LED log- arithmic audio- level meter. A 10 -LED meter can be made using a U257B and U267B pair as shown in Fig. 15, R-E What is the principal disadvantage of neon ttglits? What are out-ol-phase signals? Heath Video Courses speed your learning curve! Learn basic electronics at home at your own pace with four, 60-minute video tapes. Knov/ the variable inductor symbol. Recognize a PN junction. Understand osciliator fyndamentals. Clearly SEE what most basic electronic books can only describe. DC afCTROMCS. Covers electron move- ment to troubleshooting and repairing a simple electronic circuit. EV-3101-A. AC ElfCTRONICS, Follow-up to DC Electron- ics. Covers the principles of AC. vottage and electrical measurement. Includes motors, generators and test instrument meter movements EV-310Z-A. SBVllWWIDUCTORS. Complete the DC/AC videos and you're ready to learn how semi- conductor devices are made, plus the principles of discrete devices, integrated circuits & optoelectronic devices, EV-3103-A. ELECTRONIC CIRCUITS. Complete the basic course v/ith amplifier configurations, biasing, coupling, audio amplifiers, closed-loop vs. open loop operation and more, EV-31Q4-A. An activity-filled v/orkbook and explanation of how to solve each problem comes v/ith each tape so you learn three v/ays — video . v/orkbook and hands-orl Order todayl Call Toll free, 24*liQurs a day. 1^800-253-0570. We accept VISA. MasterCard, Americar Express and Heath Revolving Charge card. Use Order Code 601 066. Heath Benton Harbor, Ml Call for a FR^ catalog 1-800^EATH. Price does not inoludo ?) 1992 Heath Company shipping and handlSno ED'23fl'R3 Of appMoable tax. CIRCLE ON FREE INFORMATION CARD ADC FOR YOUR PC coniinu^cl trom pai^c 68 rent directory. If I he file exists, the program then lellsyou how many samples it contains, and asks start and stop points for the plot: the maximum number Is 1000. The program (line 170) scales the graph to produce the widest possible graph: lints 220-270 graph the data. Press Esc to ter- minate the program, lb ^magni- fy" a limited portion of the data set, run the program again, and enter appropriate start and end values (e.g.. 350 and 450). You can print your graphs by running the DOS program GRAPHICS, COM before GRAFDATA.BAS, Wlien the de- sired graph appears on the screen, press PrintScrn. (You must have a compatible printer in order to print out any of the graphs.) Ttiggercd sampling Now with the software under our belt, it's lime to finish the "rapper" story begun earlier. The rapper was t riggered by an electronic control circuit. We tried to trigger sampling by hand, but it was impossible to tell w^hen the rapper was about to energize, and reaction time was too slow and unsure for accurate triggering- Our solu- tion was to create a trigger in- put. We tapped a digital signal from the control circuit that changed just before the rapper triggered. The ADC circuit uses only 8 of the 24 input lines on the PC iO. What we did is usebit Oof port B as a trigger input. Then by adding a single line of code, we could trip on either a low-to- high signal: 145 IF (INP(ADD 4 1) AND 1) = 0 THEN GOTO 145 or a high-to*low signal: 145 IF (INP(ADD t 1) AND 1) = I THEN GOTO t45 If you want to add a slight delay between I he trigger and the start of sampling: 146 FOR i = 1 TO DELAYTiME : NEXT However, the delay time In this case would vary with the speed of your PC. In addition, make sure the trigger signal is TTL- compatible (logic low = OV, and logic high - 5V). If it isn t, or you want to buffer the trigger signal from your system, you can use the circuit of Figure 5, Remember, this circuit inverts the incoming trigger signal, so a positive-going trigger will be negative-going when it exits the buffer circuit. Adjust added line 145 accordingly. Conclusions The analog world of nature is not so distant from the digital world of computers. Simple cir- cuitry can allow your PC to func- tion as a digital eye. ear. or hand on the external world. The cir- cuits and software shown here are only the beginning, R-E LEARN Vm CLEANING/MAINTENANCE/REPAIR EARN UP TO STOOO A WEEK. WORKING PART TIME FROM YOUR OWN HOME! THE MONEY MAKIKG OPPOHTUNmr OF THE 1990 S EF irQu are a±rie 10 wrk wtm coarrrKin smaJI tiand toob.and^famitiuwilhba$iceiectrivKS(i e to mt vomettr, tnkfstanj DC eiectro^Ks^ IF yM possess avenge irndunial ibibtr, V(Bon«»nchu»pra^ioe4ndlearfi . then we can MKil nW VCR (natfitenance ind ftD3kM net: up 1^90% ol ALL VCff matluncttons are (^ueU! SlnqHe MECHANICAL or ELECTRO-MICHANICAL FACT: Dvcf 77 million VCRs in ute today futfonwide! 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Have make and model numbef of I equrpment used in your area ready | CALL TOLL-FREE i 1-800-284-8432 CABLE WAREHOUSE i 10117 West Oakland Park Blvd., Suite 1 515, Sunrise, FL333S1 | ^ NO FLORIDA SALES j QRCLE 1M ON FREE mFOnMAttOM CARD MOUSER ELECTRONICS Sates & Stocking Localions Katkmwide CIRCLE 117 OH FREE INFORHATtOK CARQ I HARDWARE HACKER Caller ID update, new wavelet shareware, perpetual motion again, common lab test pitfalls, and Lumeloid and Lepcon films. DON LANCASTER 1 MS Vavelets. We have got fots ■■■■of wavelets. You getcher W V wavelets here. As we've discovered a number of times be- fore, v/aveiets are a stunning new math concept that is profoundly changing virtually all the advanced electronic topics, A failure to learn wavelets now is the same as volun- teering for early retirement. We ve already seen that Jones and Barttett has published THE great new wavelets book, and that the Uftrawave Explorer from the AwBne folks is definately one fine commercial wavelet study and de- velopment program. But the big news is that I*ve just posted full working PC shareware copies of the Wavelet Packet Li- brary from Digital Diagnostics on CEnte PSRT as #365 WAVE- I LETPS. Those of you into satellite dishes and microwave electronics are now probably familiar with Smith Charts, a handy graphical method of doing ^ things like impedance matching and tuning, I have written a PostScript I Smith Chart generator that lets you instantly create all your own Smith charts in any quantity, any size, any resolution, and any where in your publication. Check CEnie PSRT' #367 SMITHCHIPS for several ( freeware samples. Your download- ing cost on this is around twenty one cents. Perpetual motion again t I get an average of three to five helpline calls a week on "free ener gy" and other perpetual-motion top- i ICS. As we have seen in the past, perpetual motion is definitely real as a historic and ongomg societal phe- nomenon. We have also seen that two ongoing sources of perpetual- I motion books, videos, and papers are High Energy Research and Lindsay PubUcations. Now, I personally feel that looking for any free-energy systems is rather dumb. First, because the de- sirability of any free energy ranks somewhere between Herpes and AIDS. Why? Because this would obviously hasten the already ongo- ing entropic heat death of the plan- et. If someone does in fact find a free^energy system, they should be spanked and sent to bed without any supper. Or. better yet. chopped up and fed to the cows. Second, because the odds of your accomplishing anything that's even remotely useful involving free energy are stupendously low. Third, because your credibility starts out as less than zero and quickly plummets. Owing to previous scams, the * not even wrong " re* search, and the "few-chips-shy-of- a-full-board" guilt by association. And, finally, because there s so much better to be doing. We're sit- ting on the greatest mountain of new hardware hacking chips, tools, rnfo. and concepts anywhere ever Stuff that s crying for hacker use, and stuff that is nearly certain to result m lots of interesting and profit- able things. Why should you ignore the obvious? Several of the recent callers were making measurements that were just plain wrong. Since I am one of the world s foremost experts in gathering incorrect, misleading, or meaningless lab data. I thought we might briefTy focus on a few of the NEED HELP? Phone or write your Hardware Hacker questions directly to: Don Lancaster Synergetics Box 809 Thatcher, AZ 85552 (602) 428-4073 ways that casuaf measurements may not end up what they appear to be. In general, you'll always want to assume that all meter pointers and. especially. a//of your digital numeric displays are lying through their teeth. Or if they are giving you a correct reading, the odds are over- whelming that the meaning and the underlying reasons for that reading are not at all what you had in mind. Oscilloscopes do a far better job than the meters or digital displays at showing you what is really coming down. Even here* an uncompen- sated pnobe. the wrong setting, im- proper sync, an invisible glitch, any outband signals, or just a ground clip that is slightly too long can cause you wildly incorrect results. It is only wtien the same tests are run over and over again by different people under* different circum- stances that you can even remotely begin to trust your instruments. Even when repeated, that trust should only apply to the exacf mea- suring conditions. Aferinstance; Figure 1 shows you a seemingly simple method to mea- sure AC power You connect your newmotors-and-magnets perpetual motion machine^ load to the AC power line through an ammeter and then separately measure the line voltage. Since power equals volts times amps, you just multiply your two readings together and you'll ? have the input power Right? S Wrong. Dead wrong. Let s temporarily forget about 5S any noise, spikes. back-EMF effects, harmonics, and non- § linearities that are certain to be I" present with your new motors -and- !I3 magnets load. Assume a pure sine- g wave voltage and a similar current § waveform. You have to take the £> phase of the current into account. You would get a zero phase shift 77 with a purely resistive bad. In a purely inductive load the voltage would lead the current by 90 de- grees. In a purely capacitrve load, the voltage will lag the cunrent by 90 degrees. Good old ELI THE ICE MAN. The voltage is ahead of the current in the eU s L inductor: the current is ahead of the voltage in his iCe capacitor And if you have any purely active load such as another generator, your current could end up phased by 180 degrees. Sourcmg, not sinking. Your actual power wilt end up as the voltage times the current times the cosine of the phase angle be- tween the two. If your voltmeter reads 1 10 and your ammeter reads 4, your actual circuit power will be 440 waits to a purely resistive load. ZERO to any purely inductive or ca- pacitive load, and MINUS 440 watts to any purely active load. Or any- thing between, depending upon your phase angle. Why is the power zero to a purely inductive load? Because of the 4 amps NEW FROM DON LANCASTER HARDWARE HACKER STUFF Hardware Hacker Reprints II or Ul 24-50 Midnight £nglni»erlng Reprints I n tred ibie Secrel Mo y Wschine 19.50 CMOS Copktiaott 24.50 TTL Cookbook 24.50 Aclive Filter Cookbook 18.50 Micro Cookbook vol I ot II 19.50 Lancaster Classics Library 109.50 AppleWrhor Cookbook 19.50 POSTSCRIPT STUFF Ask Th^ GtJru Reprints 1, II or 111 24.50 LaserWriter Secrets (lie Mac PC) 29.50 PoslScHpt Show & Tell 39^50 In tro to P 0 stScr Ep t VH 5 V I d o o 3 9,50 PosiScrtpi Oegtnner Slull 39.50 PostScrtpl Cookbook (Adob«} 16 50 PostScript ReL Manual II {Adob«] 28.50 PostScrLpt Program Design (Adobe) 22.50 Tyfie I Fort! Format (Atfot>e) 15.50 LasefWrlief Relerence (Apple) 19.S0 Heal WoiM Poslscript {Rotltl 22.50 PostScrlpI Visual Approach E&nith) 22.50 Hi Inking In PoitScript (Rekd) 22,50 LTndsl PS Pgrmmg (Holtzgang} 26.50 The V/hole Works (all PostScript) 349.50 BOOK-ON-DEMAND STUFF Book-on-demand resourco kit 39.50 G EnJ e P S RT s ampi er { 1 1 e/Ma c P C) 39 .5 0 FREE VOICE HELPLtHE VISA'MC Motors and Magnets Load FTG. 1— WHAT IS THE REAL POWER being consumed in this lesl circuit? There^s no way to teN with the setup stiown. Bui you can safaly bet that it is probably not anywhere near 440 watts phase angle. A math freak will tell you the hjli cycle cross product of a sine and its cosine is zero. Intu- itively, on the first quarter cycle, you have positi\^ voltage and current. On your next quarter cycle, you will have positive voltage and negative current. On the next, negative volt- age and negative currBnt. And fi- nally negative voltage and positive current. Add them all up and aver- age them all out and you end up with zero real power. Yes. you will get lots of back-and- forth reactive power that can give you real fits. And hack off your elec- trie utility. But your net real power into a pure inductive or capacilive toad is precisely zero. Thus. as feras power goes, at! the voltmeter and ammeter readings are totally meaningless^ And they are even less so in the presence of noise, back EMF s, sparking, or har- monics. Measuring real power So how do you measure real and reactive power? The trick is that you have to muttiply the mstantanBOus voltage and current together Then you sum to find the total power. The power of any arbitrary wave- form is equal to the DC continuous power that would give you exactly the same amount of total heating in a purely resistive load. You can do this measurement with a real wattmeter, or by measur* ing the rotational speed and direc- tion of a watthour meter. The wattmeters and watthour meters are often available through Fair Ra- dio Sales or Herbach and Rademan. BeclrDnicalty. you can use a multi- plier chip or a special RIVIS power- calculating circuit. Analog Devices is one teader in low-cost power chips of this type. Or graphically you can take plots of all the exact voltage and current waveforms, split them up into time slices so narrow that the voltage or current does not change much, mul- tiply the results of those slices and then sum the results. Note that you must multiply first and then add. Never vice versa. But you still do have to be careful Honlinearities, pulses, harmonics, motor back-EMF effects, and noise require special treatment. And most power measurement schemes have a cresf factor limit which ruins their accuracy on strong but narrow pulses. Especially things like spikes and glitches. For these reasons, it is extremely difficult to accurately measure your input power to a motors^and-mag- 2— WHEN IS A REGULATOR not a regulator? Any time that your load tries to source (rather than sink) power, a typ* ical tC voltage regulator will shut down or else become unstable. There is no current path to ground. SYNERGETICS Sou aQ9-RE Thatcher^ AZ 85552 (602) 428-4073 HHIF (open) (closed) 1 100 V 0 V 50 V 50 V lOO^iF lOO^F^ lOOnF Energy - 0.5 Joules Energy = 0.25 Joules RG. 3-OUICKLY CLOSE THE PERFECT AND LOSSLESS SWITCH. And half of your circuH energy will vanish without a Irace^ Where did the energy go? nets perpetual motion machine. If you do not know exactly what you are doing , all your results are guaranteed io be wildly wrong, And so. of course, will be all of your con- clusions. Figure 2 shows you a second measurement pitfall that the recent callers have all decided to ignore. A voltage regulator is always a voltage regulator, right? Wrong. Dead wrong. Most popular voltage regulators are onfy capable of sourcing cur- rent. If the /oad starts sourcing any power even bnefly. there is no place for the current to go, and the reg- ulator either shuts down or starts oscillating. Thus, if you have a mptors-and- magnets load, there could be times when the back-EMF effects, spikes, commutatornoise. or whatever, will try to source power back into your supposed power source. Put in another way typical power supplies and most regulators have wildly different impedances be- tween when they source and sink power Note that any normally con- nected Zener diode will behave pjne- cisely the opposite — they are great |Xn>ver sinks but poor sources. An output fjlter capacitor on your regulator is essential for grabbing and smoothing out high-frequency load sourcing variations. Beyond proper output filtering, two ways around load sourcing effects are to hang enough of a re- sistive load on your negulator that the regulator will always output a net sourcing current. Most batteries are usually capable of sourcing and sinking any reasonable amount of cunrenL Figure 3 shows you yet another way to go astray All bets are off if there is any sparking or arcing. It is physically impossible to instantly change the voltage across a circuit capacitor or the current through an inductor The usual result when you try this is sparking or arcing. Take a 100-microfarad capacitor and charge it up to 100 volts. Your energy in any capacitor is,., E = 0.5CV2 or, in this case. 0.5 Joules of stoned energy. Now. you close your lossless switch so you have two ca- pacitors in parallel. The voltage must, of course. dnDp in half, since the same charge is now spread across hviceyourptatearea. Andby the same formula, you now have only 0.25 Joules of stored energy Question: Where did the rest of your energy go? If you have a non- lossless switch of resistance R. the answer is easy. In the pnDcess of charging the second capacitor, the extra energy got burned up in your resistor as heat during charging. But go through the charging math, and you'll find that the ioss of half the stored energy is a constant which is totatty independent of the value of R! If R equals zero, then you have to get a spark and radiated energy But you still lose half of it. regardless of how good the switch is. Thus, if there is any sparking or arcing whatsoever in your machine, your readings are once again absolutely certain to be wrong. Always think carefully about your measurements and how they could be wrong or misleading. Lumelold and Lepcon films We sure had a bunch of helpline calls over the new materials stuff I announced a column or two back and in our Hardware Hacker HI re- prints. 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Dmc S^»t So Florida Sialrs] CIRCLE m ON FREE tHFORMATION CARD is one AMn Marks and his company of Advanced Research Develop- ment. Their OTC pink sheet stock is traded under the name Phototherm. This is strictly an unregistered bfue sky security; and trading remains il- legal in Massachusetts, the issuing state. Marks is a credible^ experiencedn and independent researcher with a long history of successful energy, optical-film, and pollution-control developments- Among other things, he developed the cheap glasses once used for 3 D movies. And EPRI. that ultra-conservative Efectric Power Research Institute electric utility consortium has seen fit to fund Marks with a modest re- search grant. Albeit a paltry one by EPRI standards. Coffee money. The two key patents that are in- volved in this are #4,445,050 Device for Conversion of Light Power into Electric Power, and #4.574J61 An Ordered Dipolar Light- Electric fbwer Converter. There is very little .published to date. And all of it is single sourced. None appears to be peer reviewed or critiqued. A collection of reprints is now available free on request from Advanced Research Develop- ment. One original paper has shown up as Lumeloid Solar Plastic Films and Lepcon Submicron Dipolar An- tennae on Glass, from the 1990 International New Energy Tech- nology symposium published by the Planetary Association for Clean En- ergy, located in Ottowa. Canada. As v^eVe seen a number of times in the past, you can quickly research any technical topic by using the Dialog Information Sen/ice at your local library, and then can get any reprint by using either tnterlibrary ban or the UMt reprint service. So what is the big deal here and how does it work? Your traditional methods of generating electricity from the sun are seriously flawed. The old mirnDrs and-boilers method involves a thermodynamic cycle with a Camot thermodynamic effi- ciency limit around 35 percent. Be- sides not downsizing very welL Silicon solar cells at a theoretical 26 percent are even less efficient. It seems that they can only accept "whole lumps ' of quantum energy and to throw the rest away as heat. And. before Marks, any photo* synthesis scheme v^as well under six percent efficient. Efficiency is everything in solar power On a good day. you have one incoming kilowatt per square meter to work with. Say a nickel an hour "avoided cost" income For a perfect conversion. Or two cents a day al- fowlng for night and weather. Natu- rally your bottom-line efficiency will usually be much less than your the- Analog Devices One Technology Way HomoQd. MA 02062 (617) 329-4700 CIRCLE 301 ON FREE rNFORMATION CARD Aware One Memorial Drive Cambridge, MA 02142 {617) 577-1700 CIRCLE 302 ON FREE INFORMATION CARD Bennet LaserBrtte 720 Fourth Street, SW Rochester, MN 55902 (507) 280-9101 CIRCLE 303 ON FREE INFORMATION CARD Cermetek 1308 Borregas Avenue Sunnyvale. CA 94089 (408) 752-5000 CIRCLE 304 ON FREE INFORMATION CARD Dallas Semiconductor 4401 Beltwood Parkway South Dallas, TX 75244 (214) 450-0400 CIRCLE 3QS ON FREE INFORMATION CARD Digital Diagnostics 1025 Sherman Avenue Hamden, CT 06514 (203) 288-9444 CIRCLE 306 ON FREE INFORMATION CARD Direct Imaging 2 Technology Drive West Lebanon. NH 03784 (603) 298-8383 CIRCLE 307 ON FREE INFORMATION CARD GEnie 401 North Washington Street Rockville, MD 20850 (800) 638-9636 CIRCLE 30a ON FREE INFORMATION CARD Hello Direct 140 Great Oaks Blvd San Jose, CA 95119 (800) 444-3556 CIRCLE 309 ON FREE INFORMATION CARD oreticai. Let your efficiency dnsp too low and there's no way that solar can be competitive. Get under the bottom-line efficiency of seven per- cent or so. and you will never be able to pay for your installation and landn owing to the time value of money. The longer it runs* the more it costs you for the financing. But^ alternativelyp the nickel-per- kilowatt-hour incoming solar energy on a 2200 square fool house roof High Energy Enterprises PO Box 5636 Security. CO 80931 (719) 475^918 CIRCLE 310 ON FREE INFORMATION CARD Hughes 500 Superior Avenue Newport Beach, CA 92658 (714) 759-2665 CIRCLE 311 ON FREE IMF0RMAT10N CARD Jones & BartEett 20 Park Plaza Boston, MA 02116 (617) 482-3900 CIRCLE 312 OH FREE INFORMATIOK CARD Lindsay Publications PO Box 538 Bradley, IL 60915 (815) 935-5353 CIRCLE 3ta ON FREE INFORMATION CARD Motorola PO Box 1466 Austin. TX 78767 (800) 521*6274 CIRCLE 314 ON FREE INFORMATION CARD NewTek 215 SB 8th Avenue Topeka. KS 66603 (800) 765-3406 anCL£ 315 ON FREE INFORMATION CARD Serpac 612 CofTimercial Avenue Covina. CA 91723 (818) 331-0517 CIRCLE 316 ON FREE INFORMATION CARD Sierra Semiconductor 2075 North Capitol Avenue San Jose, CA 95132 (408) 263-9300 CIRCLE 317 ON FREE INFORMATION CARD Sony 10833 Valley View Street Cypress. CA 90630 (714) 229-4175 CIRCLE 3ia ON FREE INFORMATION CARD NAMES AND NUMBERS LUMELOID & LEPCON SOLAR RESOURCES adds up to over $3000 a year Which is lots more than usually gets used underneath as electricity. So efficient solar electric conversion could connpletely blow away coal, nuclean and even most hydro. Marks has developed two dif- ferent solar-to-electric systems that seem to have rather high theoretical efficiencies. Radio waves are electromag- netic. Solar energy is electromag- netic. The main difference between orange light Cat 600 nanometers) and television channel two (6 meters) is a 10.000:1 size factor Those light wavelengths may seem tiny, but we are starting to routinely handle submicron distances in inte- grated-circuit manufacturing, There's this thing called a aystal set that you might have heard of. Just shove some electromagnetic energy into an antenna, rectify it somehow, and out comes DC power These days, we call the same thing a rectenna. So why not use light waves instead of radio waves? An antenna is any subsystem for converting radiated electromag- netic energy into conducted wire electromag netic energy. Or vice ver- sa. As a transmitter, if your antenna is now properly matched to the rest of your circuit, nearlyallof your input energy will get radiated. And, since most antennas are linear and re- ciprocal devices, tf you input any electromagnetic energy well inside of the antenna s effective area, near- ly all of it will get converted into conducted electricity. So, a property matched antenna can be TOO per- cent efficient. And a rectifier nearly so. Now, an optical antenna is trivial. Just make it any old color so long as it is black. Even a black felt tip pen will do. The trick lies in rectifying and gathering all the received solar elec- tromagnetic electricity, rather than burning it up as heat. The Lepcon panel is the older of Marks" two new developments. In a Lepcon panel, tiny rectenna ele- ments are created on glass using more or less conventional but very advanced microlithography. These are basically a conductive channel ending with a metal barrier diode. The photons in the incoming solar Key Patents: #4^445^050— Device for Con- version of Light Power into Electric Power. #4,574,161^An ordered Dipolar Light-Electric Power Converter. Key Paper: Lumeloid Solar Plastic Film and Lepcon Submicron Dipolar Anten- nae on Glass. 1990 Internationa! New Energy Technology Sym- posium, pages 201-210. From Plan- etary Association for Clean Energy below. Key Info Packet: From Advanced Research De- velopment below. Key Players: Advanced Research Development 359R Main Street Athol. MA 01331 (508) 249-4696 CIRCLE 319 ON FREE INfOHMATION CARD DiaEog 3460 Hillview Avenue Palo Alto, CA 94304 (415) 858-2700 CIRCLE 320 ON FREE INFORMATION CARD Electric Power Research Inst. PO Box 10412 Palo Alto, CA 94303 (415) 855-2000 CIRCLE 321 ON FREE INFORMATION CARD Mome Power PO Box 130 Hornbrook, CA 96044 (916) 475^3179 CIRCLE 322 ON FREE INFORMATION CARD Planetary Assoc Clean Energy 191 Promenade du portage, #600 Hull PQ, CANADA J8X 2K6 (819) 777*9696 CIRCLE 323 ON FREE INFORMATION CARD UMI 300 North Zeeb Road Ann Arbor Ml 48106 (800) 521-3044 CIRCLE 324 OH FREE INFORMATION CARD NO COMPLiCATED ELFXTRONfCS. NO EXPENSIVE INSTRUMENTS: Home study course shows you how to make good money in VCR repair. An amazing fact: you can do more than four out of five VCR repairs with ordinary tools and basic fix- it proce- dures. Our home study pro- gram sliows you how. Learn ail of the systems, mechanisms, and parts of almost all brands of VCRs. With no expensive instru- menls./Vo complicated elec- tronics. iVo fancy workshop. The step-by-step texts and close personal attention from your instructor make learning easy. Texts, course materials, and tool kit are sent to your home. Graduate ready to make up to $50.00 or more per hour in your own spare-time or full-time business. Send today for your free career booklet. Or call 800-223-4542 Name ^ Addreijs . . State . . Zip . The School of VCR Repair 2245 Fterimeter Park, Dept,V8342,Atlanta, Georgia 30341 energy are used to accelerate elec- trons, which jump the barrier diode to become a DC cunent. Unlike a traditional solar cell, there are no "whole lumps only ' quantum effects involved, and neariy all of the available energy gels converted. The antenna/rectifier combina- tion only works with one polariza- tion of light. It converts the one polarization with up to a theoretical 80 percent efficiency and passes the remainder on through. You could put a second Lumeloid pane) under- neath that is oriented 90 degrees from the first to convert the other polarization. Or. yoy could use a sneaky trick consisting of a quarter wsve plate and a mirror to nutate your rejected polarization by 90 degrees and shove it back up thnsugh the original film. Your combined efficiency ends up around a theoretical 72 percent. The projected costs of the Lep- con process is around $250 per panel and the panels should last 25 years. The Lumeloid film process uses chemicals instead of very expensive microlithography. The chemical techniques in theory lend them- selves to low-cost and high-volume production. The chemicals attempt to mimic the first half of the long photosynthesis process. A rather long chain carbon molecule, such as polyacetylene, is attached to some electron donor acceptor complex, such as porphynn and quinone. The long chain molecule acts as a conductive antenna, changing the input optical energy into electron energy The tunneling gap effect be- tween the large donor and small ac* ceptor rings acts as a rectifying diode for DC conversion. For all this to work, the molecules have to be carefully oriented while the sheet is being created, Marks work has centered on suitable bulk processes to do the orientation in a low-cost and high-volume process. Projected costs are five dollars per meter and three cents per watt. At present, the Lumeloid films are only expected to last a year in strong sunlight. Once again, Lep- con panels use conventional micro- lithography on glass, while Lumeloid use oriented films that mimic photosynthesis. Interestingly, the Lumeloid pro- cess IS totally reversible. You can input electncity and get Eight out as well. Which could lead to new light- ing and display technologies. For any of this to become real, we will need working prototype panels, credible third party research, and the proper peer review. My "usual suspects ■ of Science, Nature, Science News, and the technology page of the Wall Street Journalhave been suspiciously silent to date, My own feelings are that short and open circuits in production pan- els are going to iead to the very same type of yield problems that have he!d back and restricted de- velopment of large area flat-panel TV displays. Because of the lack of even lab prototypes, their efficiency and cost projections at this time would ap- pear totally meaningless. Caller ID update Time sure does fly when you are having fun. As a result. Ive gotten hopelessly far behind on a bunch of potentially great projects here. So my caller- ID project may take a while. Caller ID should be available in most parts of the country very soon. The controversy is dying down, since the benefits so totally and lu- dicrously outweigh any potential problems. To see what dozens of others are now thinking about caller ID, you might want to check #2239 CALLERID.CAP on the CEnie RA- DIO RoundTable. If for no other use. the con- venience of having a no-charge, no- hassle list of everyone that called you while you were out is just flat out wonderful Motorola has Just announced a brand new MCI 4544 7 caller ID chip. Free sample kits are available. This one is supposed to include in- ternal ring detection. But, as near as I can tell so far, the chip of choice remains the Sierra SOU 211, An FCC Part 68 interface is shown in Fig. 4. Which is what nor- mally has to go between you and the phone company Key points inciude an exceptionally well-balanced transformer with a 1500-vo!t isola- tion capability. While such an inter- face is fairly cheap and simple. getting the needed approval is not. Several companies now offer some ready-to go Part 68 inter^ faces. These are pnced well above what you could build your own for But they come pre-approved, elim- inating most legal hassles. Dallas Semiconductor and Cermetek are two typical sources. An interface between the new Cermetek CHIS45 and the Sierra SC11211 caller ID chip is shown in Fig. 5. Both Cermetek and Sierra have free caller- ID ap notes available. As we've seen before, a number of ready-to-use caller-ID products are available from Hello Difect. New tech lit From Sony, a new Laser Diode Guidebook. And from Hughes, a frBe brochure on their Nonvolatile Seriai Programmahie Devices. The Best of Analog Dialogue is a three decade compilation of the very best in analog linear integrated circuit design info. From the compa- ny Analog Devices. In a startling development, real thermography is now available for toner-based desktop publishing. One new source is Bennet LaserBrite. You spray on chemical A to soften your tonen dust on powder B, and then apply heat from desWamp C. Presto. Instant raised letters. Even Brailte. Free stuff this month: A video on a high-end printed circuit prototyp- ing system from Direct Imaging. A free video on the Toaster, the low- cost broadcast-quality video pro- duction system from NewTek. And a great new sample A-42 plastic elec- tronic case from Serpac. A reminder that 1 do have a full collection of reprints available. These include Hardware Hacker II & Hi my Ask the Guru t & II & III the Blatant Opportunist I. LaserWriter Secrets, and our brand new Book- on- Demand Resource Kit. Just give me a call on our no-charge tech helpline (per the box) for more de- tails. Or call me at my Synergetics. You can also reach me via GEnie PSRTC800) 638-9636. Besides that wavelet freeware and the Smith Chart package, you'll find lots of Hardware Hacker and Midnight En- gineering hard-to-find resource stuff RE AUDIO UPDATE More from the mail bag LARRY KLEIN Last month, 1 answened several hi-fi questions from readers, but ran out of noom before getting to them all This month, well get to the bottom of the mail bag. Overpriced signals? / 'm appalled by the proliferation of signal processors — particularly equalizers—in the audio market place. What ever happened to the notion that a ht-fi system should be a ^'straight wire with gain''? AT McAlester, OK The idea is alive and welt, but be- set by phtlosophicaf confusions. While the concept has validity for. say. power amplifiers, it neally can't be applied to the entire recording- reproduction chain. Straight- wire - with-gain audiophiles — for whom tone controls of any kind are anath- ema — appear to assume that what- ever signal comes out of their carefully chosen disc player or tape machine somehow perfectly em- bodies an original performance. Anyone naive enough to harbor such a belief has, at best, a very unclear notion as to how sound is recorded and reproduced. Assuming that you had a perfect stereo recording of the sound field Cat a specific location) of a live musi- cal event — and all the elec- tromechanical and electronic ele- ments in your playback system were perfect — your speakers would still have the task of replicating the acoustics of a concert hall within the comparattvely cramped space of a conventional listening room. In short, the chances of exactly du- plicating an original live sound field in your listening room are about zero. Given the aberrations in frequen- cy balance, noise level, and dynamic range likely to be introduced, plus the loss of rear ambience and reflec- tions. I see nothing wrong with using Signal processors to help minimize, ameliorate, or eliminate the various ill effects. IVe long since given up any hope of reproducing the precise sound of any original musical perfor- mance in my home. But when I achieve plausible reproduction, then Tm satisfied that IVe achieved high. if not absolute, fidelity. System imbalance After a long struggle to find the reason for my having to operate the balance contnjl on my preamplifier at the 3-0 clock position, I traced the difficulty to my speakers. What would account for the fact that a teadjustment of the midrange con- trol on one of my speakers cured the problem? JW. Freeport. TX The frequencies that corrtribute to the perception of 'loudness ' are mostly in the midrange. CYou can confirm this for yourself by noting the small effect on the overall loud- ness of music produced by the out- ermost controls of a ten-band equalizer) Hence, any control that boosts or cuts the mtd-frequenctes in a speaker system will also neces- sarily influence its relative "efficien- cy" or loudness. Alcoholic anxiety Some tape-cleaner ads seem to say that alcohol may be injurious to the insides of recorders. But maga- zines seem to recommend alcohol as a cleanser. Which information is correct? N.W Covington, LA You should avoid solutions sold as "rubbing alcohols" because they ane likely to include a skin lubricant (usually glycerin) that could be transferred to the tape and the pinch roller Ask your pharmacy for isopropyl alcohol in "NF" purity: that will work fine for heads, pinch rollers, and for general internal cleaning of your machine. Costly repairs My receiver recently went dead in one channel, and I brought it to a local authorized service center They charged me $75 to repair a unit that cost $300 when new. My friends have had similar experi- ences. Are the repair-shop owners trying to get rich at our expense — and why don > the manufacturers do something about it? K.U Boston, MA We live in a time when very com- plex electronic devices are man- ufactured by automated machinery controlled by computers. That is the reason why you can buy a digital watch or a pocket AM/FM radio for well under $10. But the elimination or reduction of the expensive hand- labor element in many of todays electronic devices is of no help when the device needs repair The repair process continues to be labor intensive, and it involves skilled, ex- pensive labor at that. In short, al- though electronic products are built by the most sophisticated auto- mated techniques available to the 20th century, they are repaired one at a time by the equivalent of an 18th-century handicraft approach. As you have found, that's not cheap! S Slam damage ^ I vB noticed that when / close the g trunk lid the cones of the woofers N installed in my car's rear deck seem J to jump forward. Can the woofers % be damaged by my slamming the S trunk shut? a EC. 1 Chicago, IL « Possibly, but not probably The variables in the situation are the rug- « BeSumlcs, \mMp[Mk contact east FREE CATALOG OF TEST INSTRU- MENTS & TOOLS IS packed wtlh thou- sands 0* products for testing . repairing, and assembling efectfonic equtpment. Featured are brand name instruments such as Ffuke, Tektronix. Leader, Waller. 3M plus many more. Also included are DMM s, hand tools, power supplies, tool kits, test equipment, static suppNes ptus many other new products. Orders placed by 4 PM are shipped before we go home! CONTACT EASt 335 Willow St,, No. Andover, MA 01845. (508) 682-2000, Fax: (509} 686-7629, CtnCLE 55 ON FREE iNFOf^MATION CARD GET YOUR RECHARGE CATALOG FREE,.. EARN BIG 5$ IN YOUR SPARE TIME— All supplies and Do-lt-Yoursetf kits with complete instructions available. Sup* plies cost from £9.95 in qty and you can sell recharged toner cartridges for S40.00 to SS5.00 each. Pnnlers include HP LaserJet and Senes IL Apple LasetWnter. QMS. etc. Canon PG-25 Copier also. CHENESKO PRODUCTS, 2221 Fifth Ave., Suite #4, Ronkonkoma, NY 11779, 516-457-3205, FAX 516-467-3223* 1-800-221-3516 CIRCLE 179 ON FREE INFORMATION CARD WORLD S SMALLEST FM TRANSMIT- TERS! New Surface Mount Technology (SMT) makes all others obsoletet XST500 Transmitter— powerful 3 transistor audio am- plilter, transmits whispers up to t mile. XSP250 Telephone Transmitter— line powered, transmits con ver sat tons up to mite. Both tune 88-108 MHz. 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If the forced outward excursion exceeds a quarter inch or so. It might be best to close your trunk a bit more genlty in the futune. However, I expect that the better I ma nufacturers of the larger car ster- eo speakers, who knew where they I would be mounted, have designed their cone suspensions to with- stand large pneumatic shocks. FM bandwidth What IS the purpose of 3 namw/ hroad bandwidth switch on an FM tuner? i Bay ShorB. NY As Far as I know, the only justiftca- tion far a n a mow- band switch is the rare case when a listener is located between two transmitters of conri' parable strength that are ad|acent to each other on the FM dial. In any case, a rotatable directional antenna ^ will probably be of more help in sep- arating the two stations than the tuner s ability to narrow its IF band* width. The narrow bandwidth set- ^ ting may be helpful if the conflicting I stations are in approximately the I same direction, or possibly when " there are severe noise conditions. Off-frequency FM Many of the rock stations in my area advertise themselves as being . located at, forexampte, "100 on the || FM dial " But my digital tuner won 't tune to even numbers: It sets itself for 99.9 or WO. I. Does something need adjustment? R.R San Diego, CA Yes — the thinking of those who like to reduce all communication to the short, punchy, and simple-mind- ed. In the U.S.. all broadcast sta- tions are assigned odd-numbered operating frequencies. 2-mega- hertz apart. Even if you could tune to 100 MHz, you wouldn*t find anything there but a lot of noise and distor- tion. But, come to think of it, that may be pretty close to what some stations are really broadcasting! R-E Engineering Admart Plans * * • SmaU Budget?? 6805 Microcomputer Development System lECl 5 MCPM 1 Vffltm allows your IBM PC ind CompaWJlM DO E» uiid 35. 1 campiete d«v?iopment syslffn lor U^ro^ 6805 Eamtfy o* singtf ch p mcrooniputefs Mirty uvtng featuTK 31 in aTlariuhlc price MCPM^I Prugrimmef ror MQtorari MCSfl70SP3, U3, U5. FU, R5 MCPM I w driver, assembler simulatof/de&uggcr W49 MCPM 4 w. driver prog ram pr?iy . $349 Also avaiEatile— Pjogramrrer lot G9HC05. in-circu?l eHiiJlalors artd FTi^rty tQ\lvfMti IodLs lo help yDu. CaN lor A cm^ltXt eatalotl and lei us tie(p von sclccl ym tools. ft The Engineers Cplljihor^Nve. Inc. Rl #3. Bdi &D Darlon, VJ mZZ USA TIL: [M^t S?SHbB (A a EW?; i:5 J*51 Cill kll Frci [MMj 33tl331 Rales: Ads m IVa'^xlW. One in5eni0n $9S5 each. S[| Insertions $950 eacti. Twelve insertions $925 each. Closing date same as regular rate card. Send order with remittance to Engineering Adfnart, Radio-Eiectronics Magazine, Bi-County Blvd,, Famifngiiale, HY 11735. Direct telephone inquines to Arline Fishman. area code-t-516-293-30fl0. FAX 1-516-233-3115. Only 100% Engimring ids sre Becepfed for this AdmZTt. Surface Mount Chip Component N^S^ Prototyping Kit|;^ CC-t CapdOtDT Kit oontafns 36S pi«£«s. 5 ed «very vBlu« htmi ipr \o 33(tr Rftsi^ior Kit contains )M0p<««3: lOoa. ErfeveryS^valu^from lon (□ \Q rnogfl Sii« aro 0S05 and 12Dd Each kii is ONLY S-t9 95 ond AvaHablo ro^ tmmediata Om Day Deltverv! OrtJer by toH-lree phone, FAX. or mall, Wo accept VISA, MC, COD, or Pre pa Ed ofders. Company RO.s accepted with approved cfedJt. Call lor ffoodoiallcd brochure, (WMUNicATms sPEmusrs, m. 426 West Tatt Ave ^ Orange, CA 92665^2% Local {7t4) 99ar302l - FAX [7U)W!A M20 EntFro USA 1-800-S54-0547 FCC LICENSE PREPARATION Hio FCC has revise and updated the oonnmefciat license exam. The NEW EXAM covars updated marine and aviation njies and regulations, transJstof and digital circuitry. THE GENERAL RADIOTELEPHONE OPERATOR LICENSE - STUDY GUIDE contaifTs vilaJ information, VIDEO SEMINAR KfTS ARE NOW AVAILABLE. WPT PUBLICATIONS 7015 N.E. 61st Ave. Vancouver, WA 98661 Phone (206) 750-9933 Dept. 50 CiRCLE 196 ON FBEE INFORMATION CARD CIRCLE 181 ON FREE INFORMATION CARD CIRCLE 185 ON FREE INFORMATION CARD NEW LITERATURE continued fmm page 27 mation. complete specifi- cations, and operating range data, are provided for more than 50 models. A five page summary of spec- ificatior^s and ranges is or^ ganized by instrument type to help the reader make model-by-model com- parisons. Besides being chock full of test tnstru- ments, the catalog de- scribes protective cases that are tailored for individ- ual models, and a complete line of accessory test probes, cables, and test lead kits. THE HIDDEN SIGNALS ON SATELLITE TV: THIRD EDI- TION; by Thomas R Har- rington. Universal Elec- tronics, Inc., 4555 Groves Road. Suite 13, Columbus, DH 43232; Phone: 614-866-4605; S19J5, plus S3. 00 shipping and han- dling. Everyone knows that you can pick up video signals with a satellite dish, and most satellite owners know CIRCLE :i7 ON FREE INFORMATION CARD that they can also receive audio channels on re- ceivers equipped with tunable audio subcarrier sections. However not many people are aware of the variety of n on- video and data services that are also carried on sateflites. Those services include au- dio newSp stereo subcar riers. telephone systems, world news and press ser- vices, teletext, single- channel-per- carrier CSCPC) systems, stock market reports, financial news services, and busi- ness data channels. This book covers all phases of this expanding side of the satellite business. Begin- ning With an explanation of the transmission and re- ception of satellite signals, the book goes on to pn3- vtde details about each of the systems transmitting hidden signals. It describes each system and how tt works, explaining who uses it and how the reader can receive it. The book also includes glossaries of data-communications and satellite-system terms. THE ARRL HANDBOOK FOR RADIO AMATEUflS 1992; Ed- ited by Charles L, Hutchin- son, K8CH and Joel P. Kleiciman, N1BKE. American Radio Relay League, 225 Main Street, Newington, CT 06111; $25.00. Everything you ever wanted to know about am- ateur radio — and then some — can be found in the more than 1100 pages of this book. Aimed at hams, technicians, and engi- neers, the book provides a thorough introduction to the basics of amateur ra- dio, including electrical fun- CIRCLE Mi ON FREE INFORMATION CARD damentals. the techniques and terminology of radio design, and the basics of solid-state and vacuum- tube sets. A comprehen- sive section on radio princi- ples covers power sup- plies, audio and video communications, digital basics, modulation and de- modulation. RF oscillators and synthesizers, princi- ples of radio transmitting and receiving, trans- ceivers, repeaters, ampli- fiers, antennas, and trans- mission lines. Modulation methods for voice, digital, and image communica- continued on page 102 !^ J] 9 m o n 3 3 87 .):fnvji:in: ^^^^^^ Our long-lost discussion on digital ^RDBERTGROSSBLAT^^^ Weli, it s been a while com- ing but. at long fast, weVe finally back to talking about digital scopes. There have been some interruptions In the meantime but that s the way life is — it sometimes interferes with lEving. This subject got put on hold for a bit because of the business of voltage regulators. Sorry about that but, even if you don't have any particular interest in cars or motorcycles, all that information should be put away for future reference. You never know Just to refresh all our memories, we had been talking about the things to be considered in designing a circuit that would serve as the beginnings of a digital scope. All scopeSp even the one we're going to design, have certain basic things in common and any project you have in mind that involves scope design has to start out life around these funda- mentals. Your ultimate goal may be to construct something that's big- ger, fasten or (to use my favorite phrase), "feature rich/' but no mat- ter what you have in mind, when you're just getting started it makes sense to approach things from the beginning. The design criteria for the scope we are going to be putting together are the following: 1. The scope will have a maximum bandwidth of at least 1 MHz. S 2. There will be eight selectable ^ sweep speeds. I 3. There will be eight selectable gain ^ levels, - 4. There will also be a variable gain ■f control 5 5. The display will be in a twenty- by- M twenty matrix. 6 The block diagram of the scope IS we're talking about is shown in Fig, ^ 1. While you re looking at it keep in mind that, even though we're only 83 talking about a demonstration cir- cuit, the basic structure is the same for every scope there is. Once you go through the design of a simple scope, it'll be much easier to under- stand the workings of more com- plex ones. There are all sorts of interesting things that can be done with the scope we're building and there s no reason whatsoever why you can't take the basic circuit and add any- thing you want to it. But weVe get- ting ahead of ourselves. One of the major players in the accuracy of a digital scope is the timebase. Ordinarily, in a simple scope such as ours, the timebase is an RC-type circuit that gives you. . . well. RC-type accuracy. But just be- cause we're not building the worid s most complex scope, there's no reason why we have to settle for so- so accuracy. Whenever you want accurate timekeeping, the answer is a crystal-based circuit, and that's what we'll use here. There s no shortage of circuits when it comes to building a crystal oscillator, and the schematic shown rn Fig. 2 is as good as any If you need frequencies up in the many megahertz or even the gigahertz range, you'd have to devote a lot of time to this part of the scope, but since we Ye keeping everything to under one measly megahertz, this schematic is a simple answer to the problem. I've picked one megahertz for the basic crystal frequency because it's a nice even number to work with and t^MHz crystals are readily available. You shouldn't have any trouble get- ting the 4049's to work at 1 MHz— even if you're only operating the cir- cuit at 5 volts. If you have any prob- lems, up the voltage to 9 volts or so (working with CMOS stuff is great!), and that should take care of the problem. Should you want or need to stay down at 5 volts and you find that the fNpur TF 31 FIG. 1— BLOCK DIAGRAM of our oscilloscope. The basic structure is the same for every scope there ts. oscillator isn't self-starting at that voltage, use an equivalent high^ speed CMOS part like the 74HCT4049. Most of the mail- order houses carry the 74HCT fam- ily and you'll find that they* re all fast- er than the 4000 series and just as reliable. Just about the only restric- tion you'll have is that 74HCT parts have the same voltage restrictions as TTL. They want a supply voltage of 5 volts and going any higher than that IS a sure way to cook the chip. Once we have the timebase cir- cuit working properly, the next step is to do some straightforward fre- quency division to generate all the sweep speeds we need. First, how- ever we should decide what those sweep speeds are going to be and. even before that, we have to work out how the horizontal part of the display is gomg to be conceptually organized. Our dispfay is going to be, as we specified, a twenty-by-twenty LED matrix. There ane twenty columns of LED's and each column is going to be enabled in turn for a particular length of time. When we refer to the sweep speed, we have to dis- tinguish whether we're talking about how long it takes to sweep across the entire twenty columns or how long each of the twenty col- umns is enabled. If you look at the sweep-speed settings on a standard os- cilloscope, you'll see that it's marked in seconds/division. Since our display is made up of separate FtG, 2— A CRYSTAL OSCILLATOR for our scope. For frequencies below 1 MHz, this schematic is a simple solution. y'6^oM9 /OK r— IDI — \ Jk. Ct CZ A' 3 C 3 /s FIG. 3— THE 4520 DUAL SYNCHRONOUS BINARY COUNTER will provide us with a series of frequencies that are accurate enough for the kind of circuit we're designing. columns, we can translate that into seconds per column. Therefore, we'll arrange our sweep speeds around the time each column is en- abled, and not how long it takes to cycle through all the columns. That is important to keep in mind be- cause we want to be able to get a rough idea of frequency when we're viewing a waveform on the scope, and the standard way of doing that is to count the number of divisions covered by a complete cycle. Since each division relates to a particular amount of time, you can estimate the period and calculate the fre- quency of whatever w©veform is being displayed. Standard oscilloscopes use a 5-2-1 counting sequence for divid- ing the sweep frequency. That means, at a basic leveln that it takes the trace five. tvro. or one second Cor some fraction of a second) to cover each division. The maximum sweep speed we can reasonably ex- pect to have is about TO microse- conds since there are certain limitations to LED intensity, con- struction methods, and so on. It's possible to do a lot better, but the stuff you have to worry about has nothing to do with the basic design of the scope itself. The lowest sweep speed that makes sense for the scope we're working on is about a tenth of a second per column. The major fac- tor here is that when you get much slower than this, it gets increasingly hard to visualize the waveform on LED's. Remember that the scope will be enabling one column at a time and only one LED in each col- umn will be lit. If the sweep speed is too slow, the eye won't be fooled into seeing several of the columns lit at the same time. Once we get the circuit working, you can experiment with the range of sweep speeds and see what the outside limits are. The top limit is a function of electronics but the hot- tom is determined by considering the persistence of the retina and other biological factors. If you want to drop the sweep speed to one second per division because you have a particular need to do that it s relatively simple to set the elec- 3 i Q. s 09 45 Ways to Help You Qualify for the Job You Want Free Facts about Career Dtplomas and Degrees tic.'* (iS ngme m your spare nme. wilhoul any previous expenertce, ycu can tram for ' a money-making career .even get a SpectaUzed Associaie Degree. Call or ' sertd for free inrormation on ihe career field ttiat | interests you hk^ and how to train Jor it. ,1-800-234-9070Ext.488 OB WAJL COUPON TOP AY! IrTiernaliGnai Correspondence Schools I AISOCUU LN SPtc:AlJr[[^ I n lNpfiC^«M«fia ppiit . ' CH[CK"t>HE"&DX OH^f A^socuTi IN sncututo TEDMOLCWT DCGRIE PROGRAMS : C^M E^^C'f"**t^^ Technol&j/ □ 0KBc^ Engnermo fecn DflKiHangTBEliBeiiiiy Ol O joimfewShofi Sto(v Wftna □fJwtsJ , PFtedncan I I Mi I A ■:,i^n) I Nirne. I Clly/Stili -Apt. _Zlp_ Ironies to do it. The best way to get an tde3 of whal it would be tike is to sit in front of a real scope and play with the sweep-speed control Now that we know the sweep- speed range — from a low of a tenth of a second CIO Hz) to a top of 10 microseconds ODO kHz) per divi- sion — we can decide what the re- maining six sweep speeds should be. Generating divisions in the stan- dard 1-2-5 sequence is certainly possible but it s also a pain in the neck to do. We can cut this part of the design way down and reduce the needed parts to a bare minimum if we let the relationship between the sweep speeds follow the standard 1-2-4-8 binary sequence. By doing that, we can choose from a wide variety of standard binary counters and. as you can see in Fig, 3. that s exactly what Ive done. The 4520 is a dual synchronous binary counter and will provide us with a series of frequen- cies that, while not exactly whole numbers, are close enough for the kind of circuit we re designing. Remember that the resolution of the scope we're building isn*t all that great in the first place. Feeding a standard CMOS part like the 4520 with a clock as high as 1-MHz is an iffy business — es* pecialty as we discussed a while ago. if youVe running off a supply that s down in the range of only five volts or so. If you have such a prob- lem, the ways to get around it are the same as the ones we talked about eadier; you can either raise the supply voltage or use 74HCT4520S instead of the stan- dard 4520. The two 4520 s in the circuit give you a choice of sixteen clock fre- quencies (seventeen if you count the basic crystal frequency), so you have lots of sweep-speed choices. When we get together next time, well finish the horizontal circuit and go through the design of the vertical amps and driver circuit as wefL R-E EQUIPMENT REPORT continued from page 16 CIRCLE 108 ON FREE INFORMATION CARD the manual says to install C40, a 22 pF, 16-volt electrolytic, but the actu- al part, as shown in the parts list, is 22 p-R Also, a spring must be in- stalled to the left of the 7106 IC to ground a metallic shield in the back of the meter housing; the instruc- tion manual does not clearly show where the spring goes. Other problems included R43. one of four 1 -megohm resistors to be installed, but the parts (rst shows only three t -megohm resistors and R43 as lOOK— also, the lOOK re- sistor was missing from our kit. Re* sistor R7 is said to be installed as 900K but the parts list shows it to be 898 ohms and that's what was included in our kit. Likewise with R8; it s installed as 100K but listed and included as 100 ohms. Another 100- ohm resistor, RX. was not among the parts included in our kit, but they did include an unnecessary 75K re- sistor — perhaps it was intended to be close enough in value to R43. Resistors R09 and R17 are to be installed as 9 ohms each but listed as 8,98 ohms. Neither of the two remaining resistors were color-co- ded for 8.98 ohms, but they mea- sured about 12 ohms. Close enough we decided, and the meter seems to work just fine. You never know exactly what s in- side something until you take it apart, so you can't help but be famil- iar with the basic insides of any mul- timeter once you build the /OOK. The finished WOK is a sturdy capa- ble meter, and certainly worth its price. And although we feel that it's a pretty decent meter and a great project for someone new to elec- Ironies, the help of someone more experienced might be necessary. However, we've already pointed out the kit 's sore spots so if you plan on building one you should save this review as a guide. If youVe read this review and would like to own a WOK but don't ' want to build it yourself, the WOK is available preassembled. And the as- sembled WOK multimeter actually costs ten dollars less than the kit {$19.95X Thats because it costs more to package the unit in pieces, and the kit includes a 47-page as- sembly manual. R-E COMPUTER CONNECTIONS Pen-Based Computing JEFF HDLTZMAN Pen-based computing is one of this years hot topics. At first glance, this new class of device seems to be more gadget than computer. On closer examina- tion, howeven it looks more like a glimpse of the future. As with many hot topics in today's computer world, pen-based com- puting got its start at Xerox PARC CRalo Alto Research Center), a re- search division of the corporation mostly famous for photocopying, but whose basic research has fu- eled much of the personal computer nevofution — but that s another story. In 1968. a fellow by the name of Atan Kay, now a researcher at Ap- ple, put together a cardboard model of something he called the Dyna- book. Kay didn't call it a computer; he intended to suggest something far larger, more grandiose, more connected, and more accessible than any mere data-pn^cessing ma- chine. The original design called for a notebook with a megapixel screen, multiple CPUs, and wired and wireless networking. Since then Kay realized that the hardware alone was not enough; a user-friend- ly (Macintosh-fike) user interface would also be required. Even more important, a cooperating system of software "agents" would assist the user in gathering information and performing routine tasks. Agents are not yet ready for prime-time. User interfaces have evolved con- siderably since 1968, but still have a long w^y to go. Perhaps not sur- prisingly, as in most areas of the computer business, the greatest strides have been made in hard- ware. Since portable computers, taptop computers, and notebook comput- ers first started to appear, several companies have released subop- timal designs bearing the title Dyna- book; however. It is only the very latest generation of pen-based ma- chines that even dignify the con- cept. NCR released the first of this new breed in the spring of 1991: fall COMDEX in Las Vegas saw the re^ lease of a spate of new machines by other vendors. This first generation of commercial machines illustrates several points: (1) The Dynabook concept is valid, but C2) current hardware and software have not fully achieved the vision; even so C3) there is a light at the end of the tunnel. Hardware and software The typical pen-based machine is about the same size as a notebook PC (8.5" X 11" X 2\ less than five pounds). The current generation typically has a 286 or 386SX pro- cessor, a few megabytes of memo- ry, a floppy drive, possibly a hard drive, and a slot or two for special credit-card sized memory cards (these cards have now been stan- dardized; more in a future install- ment)- Usually there's no keyboard, although there are 'convertible" units that allow both keyboard and pen input. Some units, such as Grid's GridP&d RF (shown in Fig, 1), allow wireless connection to stan- dard networks. Overall, the most interesting thing about pen-based machines is that the screen is used for both input and output. Using a special stylus, you draw, write, and edit directly on the display sur- face — it's like an intelligent Etch-A- Sketch, one that allows you to store and recall text and graphics. It's what some calt a direct-manipula- tion environment (DME), If there's no keyboard, how do you use the thing? There are three basic approaches. The first simply glues a pen-input interface on famil- iar operating environments (DOS or Windows). The second creates a rich new environment CGO's Pen- Point operating system). The third creates a limited new environment, one that restrains cost and power in service of specialized applications. Microsoft, as might be expected. has adopted the first course. The company has defined a set of pen- oriented extensions to the Win- dows environment, called Windows for Pet) Computing (WPCX This en* vironment is scheduled to be re- leased in the first quarter of 1992. right after Windows 3.1. WPC has already garnered support from some three dozen hardware ven- dors, including AST. Dell, Grid/Tan- dy. NCR. Zenith. Sharp. Sony Toshiba, Tusk. Momenta. NEC. Samsung, Sanyo, and many more. Currently Grid owns more than 50% of the market, but in five years that s expected to drop to about tO% of the current level, with Sony, Toshiba, and Sharp accounting for about 36%. and IBM and Apple to- gether for about 30%. Hundreds of software developers have also shown support for WPC. A company called GO Corpora- tion has pursued the second option with a product called PenPoint, the chief competitor to WPC. PenPoint has not achieved as much support as WPC Cyet). but the support it has achieved is quite meaningful IBM. for instance, has licensed PenPoint, and has shown it running on a to-be- released pen machine. Apple is evaluating use of PenPoint versus its own internally developed pen^ based operating system for a soon- to-be -released pen machine. Although extending an already popular environment has some ad- vantages, some feel that a whole new way of looking at things is re- quired. This new paradigm returns to square one in the process of thinking about how people can best interact with a computer For exam* pie. the select *do paradigm Ce.g., select text, press Delete) of Win- dows may not make sense in a di* ^ rect-manipulation environment. In a gj DME you might simply draw a line ^ through unwanted text. It s more di- I rect. more natural, more efficient, -g more comprehensible by computer novices. This is the tack taken by 8 PenPoint. 9 A related area is compound docu- B ments, documents that include text. ^ graphics, possibly other media. ^ Windows is just about to the point ^ where building compound docu- ments is reliable and efficient. By 92 contrast » PenPoint has been built Gesture Meaning PldCGS ihfi jfiseriiDn point s (Elects A'here ytJu isp Ihc pen aGicicis ill ciiaraciers unasf inf nnv. A Eater^cl^ TMe se^sction to tf^e Jocairor: vvtiere vt3u df3w The qesJyre Deleter the current seltctton di the chafscter lo dit fight of the irtsertion DdIdIOS wofds or objects iindciria'JtM the gt^slure. X Bnchttpacts and deletes tho character to the left of thn insertton paint tupMunair Insefts sp^ce at the insert on point (OptapnaE, can atso hi? positional! in»cii} tf iiBW imc inQiuinf di inc inMJJMiff pfunir i^upiHjniiii csf* m; politic nail liT!,erL'; d Tab at the insertion point (Optional, can also bo positional} / V Places tlio chsclEGd word of solec^ton ift the Edft Tfit drsloy hox.. y Cus^ ^ei&ctFOfv and places it on the Cliphaard Copm the sefeciiofi and ptsctt it ort the XSs^^o^. A Posicis iha contents or the Clipbtiard at the msertion pE>mt {Optional; can also bo posdional] tf Royorses the previous action, 1 Gcsiure Meaning l4 Select/lnvQke ® I Inttisre drag Imuvt. ^vtpc through) •• Itritrate drag (copyl Flict i^oui directions) j %^t^\\ Bfowse Doss oui X Oeliii Scratch oirt Delete CircfB o Edit Options Caret A Insert Brackets [] Select object, adjust selection Pigtatf (vertical) / Delete character Oown right L Insert ^puc^ FIG. 2— PEN-BASED GESTURES differ between Microsoft s Windows for Pen Corn- putt ng (a) and GO Corps's PenPoint (b). from the ground up lo support Em- bedded Documertt Architecture CEDA). With EDA, you just grab somethtng and start working on it. If It s textn a text-editing window pops up; if it's graphics, sizing/shaping handles appear This focus on the document, rather than the appltca- ttons used lo produce it. is what will make pen PC's attractive lo novices, and to the those of us tired of fighting the battle for integration. Defenred 1/0 is another interest- ing capability of PenPoint, It allows you to "send** documents to other people, regardless whether you're plugged into the company network or riding a camel in Riyadh. If the hardware can t physically send the file when you make your request, it adds it to a queue and sends it when the required resources become available. Likewise with modem out- put, fax output, and printer output. Gestures Both PenPoint and WPC make use of gestures, pen motions that signal an intent to do something, and depending on the operation, the data to which it is done Ce.g., striking a line of text). Gestures come in several sizes and shapes, depending on the system; and spe- cific gestures tend to be inconsis- tent from system to system, as shown in Fig. 2-a CWPC) and Fig. 2- b (PenPoint). (This is equivalent to the once-heated argument about whether the Delete key should work on characters to the right or left of the cursor. The vast majority of users simply didn't care, as long as usage was consistent from program to program.) PenPoint demonstrations are ex- tremely compelling. But Microsoft is Microsoft, and Windows is Win- dows. Does PenPoint have a chance? Its simply too soon to tell The Windows juggernaut is rapidly crushing everything in its path; GO is working hard on data portability, so there's a good chance it will at least survive. In any case, most hardware vendors are playing it eafe and supporting both operating sys- tems. Phoenix has even released a dual-mode BIOS that provides low- level support for both. Theoretically, anything that runs under Windows should run under WPC. PenPoint is in a more pre- carious position regarding applica- tions; however, WordPerfect and Lotus are converting and develop- ing applications, and several other companies are developing new ap- plications, including telecom- munication, word processor, spreadsheet, network interface, outliner. PIM. and more. Some developers are targeting applications for both environments. Slate is one interesting example. The company has introduced a product called Pen Book that allows you to take any file in PostScript format and convert it for use in a pen environment. The software allows you to build a table of contents and link specific pages to it. It also in- dexes the text. Rather than 45 pounds of manuals, imagine being able to take a notebook with all rele- vant sen/ice information on a house call, and instantly locate the desired information with a few taps and flicks of the pen. There's potential here. Who cares? Companies marketing pen prod- ucts see two initial focii: highly mobile personnel (e g,, doctors and nurses, delivery people, sales peo- ple, insurance sales people and ad- justors. etc.) and professionals who travel a lot. Mobile usage is already happen- ing. For example, a major pharma- ceutical company recently pur chased 1000 pen units from Grid for on-site sales; the San Jose Police Department is evaluating use of Grid machines to reduce paperwork Some industry veterans feel that pen computing is just another over- hyped technology, with little main- stream application. More informed sources, those with a little historical perspective, see the potential. It will take a few years, but by the end of the decade, most of us will be carry- ing "pentops" and wondering how we ever got along without them. News bits Last time I talked about the sig- nificant effect that multimedia will be having on the computer industry, the publishing industry, and society in general. At the time. 1 wondered how IBM planned to get involved. Shortly after my deadline. Big Blue announced a wide variety of prod- ucts and services under the banner ' multimedia." The software (dis- cussed last time) fs in some ways the most interesting part of the an- nouncement; however, there are some interesting hardware goodies as well, including a device that lets you broadcast and receive televi- sions signals across a token-ring network simultaneously with normal network traffic, thereby setting the stage for real-time video-conferenc- ing. IBM also co-released with Intel a $2000 NTSC video board, called the ActionMedta IL that allows play- back of digitally recorded video. CA $900 add-on allows digital record- ing,) The basic technology is Intel s DVI (Digital Video Interactive); the board, though it may sound expen- sive, is about half the cost of the previous version, occupies half as much space, and reportedly pro- vides about twice the performance, in addition, the company released a rather weird multimedia PC (the M57SLC} that includes a high-per- formance CD-ROM drive, XGA graphics, 16-bit audio capture/play- back, and a souped-up 386SX pro- cessor that sounds like a 486SX crammed into a 16-bit package. After years of promises, Philips finally unleashed its CD-I (Com- pact Disc Interactive) technology on the consumer market under the name Imagination Machine. It costs in the neighborhood of $800, but does only one thing. Conversely, you can upgrade your PC with a CD- ROM drive and a slew of useful soft- ware for that amount of money, have change in your pocket, and have a general-purpose tool that's truly only limited by your imagination. I think Philips' marketeers inadver- tently hit on the right name, but for the wrong reason. The only imagina- tion is in the amount of sales CD A will generate. On the software front. IBM has delayed release of a fully functional Ci,e,. Windows compatible) version of OS/2 2-0 until the end of the first quarter of 1992, In the mean- time, Microsoft will sell anothercou- ple million copies of Windows. However, Microsoft also slipped its ship date for Windows 3.1 until the first quarter of 1992. but has pub- licly shown a fairly robust version of Windows NT (New Technology), betas of which will be shipping to developers by the time you read this. Digital Research released DR- DOS 6.0, the major addition to which is RAM-based task switching and some utilities. It seems like a good product, and three or four years ago would have been a great competitor to DESQview. R-E Nifty, huh? , . . / built thix fwn' drht' out of it nuutcr, BUYER'S MART FOR SALE TUBES: "Oldest. " "latest." Parts and schematics. SASE for lisis. STEINMETZ, 7519 Mapfowood Ave., R E., Hammond, l^f 46324, RESTRICTED technical information: Electronic survoillanco, schomalics, locksmilhing, cover! sciences, hacking, etc. Huge selection. Free brochures. MENTOR-2, Dj'awer 1549. Asbury Park, NJ 07712. FREE CATALOG . CABLE T.V, BOXES - ALL TYPES ■ - LOW PRICES - DEALER PRICES - FREE catalog. Books, periodicals on iDchnology; in, out of print. BRIAN MCMILLAN, BOOKg, {319H7B-2360. ELECTRONIC supermarket surplus prices! Transformer specSals, railroaders, builders, engi* neers, e^(perrmenters. LSASE. FERTIK^S, 5400 Ella, Phila., PA 19120. TUBES, new, up to 90% off. SASE. KfRBY» 296 West Carmel Drive, CarmeL IN 46032. QuaNty Mtcrowaue TV Antennas ■ WIRELESS CABLE - IRS - MM05 - Amjieuf TV Unn HJfh &iin 5(Mb|^) * Itseib^ I.S to 2.7 Gfu. * 12 OiVH»ISy5t«rTfCaTi{JtettSn4g5 - m w write jSASE} !or ■"FFtEi" Catalog PHILLIPS IE£t^ ELECTRONICS P.O. Bai 8533 . 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NON-COMMERCIAL RATE: (foe inilividuals who wan! to buy or solt a personat rtem) S2 50 per word, prepaed. ..no mmFmum ONLY FIRST WORD AND NAME set in bold caps at no oxira cftafge. Addiiional tMld fac^ (no! available as Qsl quality, all typos avail- at3le, CNC CONCEPTS, INC, Box 34503. Min- neapolis, MN 5S434. 1 (800) 535-1 B43 JERROLD, Tocom and Zentth ^1»st" chips. Fully activates unit $50. QO. Cable de< tcrambters from S40.00. Orders 1 (fiOO) 452-7090. Ififormatton (213) 887-0081. TEST equipment pfe-owned now at affordabte prices Sagnal generators from S50 00. os- oJloscopes from S50.00, other equipment, includ- ing manuals available. Send S2.D0 U.S. for catnlog, retunded on Isi order, J,B, ELEC- TRONfCS, 3446 Dempslor. Skokio, IL 60076. (70ej 962*1073. CB RADIO OWNERS! 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MCM is canstantly in touch with national and International manufacttirers to hring both commonly used and hard-to-find products to its customers. There are over ITJDQ items stocked and ready for neit day delivery, mclyding: semmonifiictors, connectors, audio and VCR parts and accessories, television parts, hardnrare, test eqtJipment, chemicals, tools and many namt brand items. MCM ELECTRONICS ^^^^ A P/t£M/£R Conip^y AT MOM ELLu i R anCL^ 07 ON FAEl INFORMATION CARf> Advanced solid-state LASER which Will pm-duoc n n^^lt^V: tt:4 POLARIS fndustries Ul W. VVjdica Hd.. Suillc 3IW-B AElttnia CA. ri3 T^Jl J4 H™f PnV* In?*- 1-800-222-5620 PIONEER for Warner system. Digiral insert for your SA-a. Changes WJlh their signal. Si 50 00 wllh simple instructions andguafantea NEEDY'S ELECTRONICS, US Hwy 23 South. Weber City, VA 24290. (703) 225 3334,fa)C ^703) 225-3296. LONG play cassette recorder — Records 12 hours on a singEe standard cassette. Voice-acti- vated. Also miniature long play recorders, mini microphones, teEephone recorcf controllers, stun guns, surverdance/countermeasures devices. Catalog S2m PRODUCTIVE EUEGTHOMICS, Box 930024 R, Norcross, GA 30093. PLANS AND KITS FASCINATING electronic devices! Da^ersl Lasers! FM/A My phone trans mi Iters! Do lectors! Kils'assembledi Catalog S2.00. QUANTUM RE- SEARCH, 16645-113 Avenue. Edmonton, AB. TSM 2X2. HOBBY/broadcasting/HAM/CB/surveillance transmitters, amplifiers, cable TV. science, bugs, other great projects] Catalog Si. 00. PAN AXIS, Box 130-Fg. Paradise. OA 95967. PCB and schematic CAD. S195.O0 IBM EGA CGA Mullilayer, rubber band, auiovia, NC drill, laser, dot matrix, ploiter, library, Gerber, AUTOSCENE, 10565 Bluebird St., Minneapolis. MN 55433. (612) 757-8584 free demo disk. DIGITAL recorder Digitally record any audio source with special effects. Microprocessor con- Iroiled device Detailed plans, S9.75: T. ZURAW. Box 341, Dearborn Hts, Ml 46127. PRINTED cifCuil art work. Low cost, for free infor^ mation write NEGRON ENGINEERENG, 159 Gar- field Place, Brooklyn. NY 11215. Fax or call (7lfl) 76B-4Q23. VIDEOCIPHER 1 1, scanner/cable/ satellite modi- fications books. Catalog — $3. 00. T6LEC0De, PO Box 6426 RE, Yuma, A2 85366-6426. REMOTE CONTROL KEYGHAIN •Complelc w/niirt^irammftlcf and +S vdt: RF racoim Fully o^icn-ibtcd mctuding pinna b bu:ld your own auto atami Qyantity discounts av^ailabJc (!* n jH ft C Cht3ck,V[sa or M'C Add S 3 atiippSnfl 8oK 14158, FremonLCs. 3*4533 VISITECTINC. (510)651-1425 Fax'(510)65Va454 MOW build your own Regulated 12V0C to 120 VAC, 300W to 500W Inverter, a must lor campers or emergencies. Includes complete schematics, parts and manufacturers lists and morel Send S19,95 to INVERTER SCIEfJTfFIC. Box 778. Suffern. NY 10901 REMOVE LEAD VOCALS . Fnorn R&cords h CD's Build chis kJt tor wid« $60 whtchl clw« r«eorda, CO'c. tif»s or brtadcHb. Eittly onrwcc^ to any homff compcntTii avK. Pvlom b« ttiB lead tin^vr ot ygtyT fevixil* band. D6tili*d Pa»ia. iM M Weeder Tcchnologiea 14n3 Lindsey Rd Mt Orab.OhJo45lS4 J DESCR AMBLER kits. Completecable kit $44,95. Complete satellite kit S49.95. Add S5.00 shipping. Free brochure. No New York sales. SUMMIT RE, Box 4a9> Bronx, NY 10465 SURVEILLANCE transmitter kits tune from 65 to 305 MHz. Mains powered duplex, telephone, room, comb in a! ion telephone/room. Catalog with Popular Commiinlcatiorts, Popular Elec- tronics and Radio- Electronics book reviews of ^'Electronic Eavesdropping Equipment De- sign," S2.00 SHEFFIELD ELECTRONICS, 7223 Stony Island Ave.. Chicago. IL 60549-2806. ROOM surveillaiice telephone Si 75.00. Room and telephone monitor ^275.00. Remote tele- phone recorder S479 00. S3.0G catalog LISTEN ELECTRONICS, 603 Etgin, Muskogee, OK 74401. (913) 663-9569. SATELLITE TV descrambler. Build your own. Easy to follow instructions, parts list, circuit board, wiring diagram, $9.95. ABG ENTERPRISES, 27081 A. Halifax. NS, B3H-4Me. REMOVE VCR copy protection PCB PAL instnic- tions 516,50 w PBiH NORM HOGARTH. 955 NW Ogden, Bend, OR 97701, TOUCH tone decoder displays dialed number. Store and retrieve up to 256 numbers, input from phone, scanner, tape. SASE for brochure. WIND- ESIGNS, Box 200091 R, Denver, CO S0220-0091. 96 Ferro Fluid Pro-Tftch ferro l.uid i$ commonly used on vobe coils lo substanlially Improve frequency responi^e. increase (rariBient and conilnuous power h and fing capabiriifes and reduce second and ihird order harmonic d isJonion. It r od u ess th e O and towers the in^edance peak at resontince wilhout a &ignllicart reducibn In SPL Goneral _ purpose fluid lor tweeters and mid^angas only. 5cQ bottle. #RG-340-431 $10 95 Each Light Oak Speaker Cabinet PfefrJum ported speaker c^bi- nei made of acocjstxal grade pa rtide board a nd covered with alighi oak vinyl laminate. Prs- cut with an 1 1' holo for u^e with fTJOSl 12"' ¥rtJofers. The t^afikJ board has no tweeier or mid range ho les lor dosign fJex- baity. The IhcK particle board ensures low panel reso- nance, DErnensions: 1 I'k 15'x 2T, Vofume: 2.5 cu ft. Grill and lermina! indud&d. Sold individual^. $49- $39^ Each j gMjp} #RC- 262-1 00 12 Gauge Neon Wire Th® competition in today s aeso sound contests Is so llorce that good sound atone is not enough to win^ Mora and mora installers a^ro striving 10 make theif insialtation HTOfo plaasing to tha ©ye. Parts Expf&ss now stocks 12 gauge spe^iker wire in vibrant noon colors. Thfe wire is the same high quality, made Jn ihe U,S, wire you have used bofora. but now ll has fEashy, neon colored insulating lackats. Available in neon pink, neen groan, and neon oranga. SokJ by iho toot ort or 50 tt. spools. #RG-T00-162 {Neon pink) #RC'100-166 (Neon orange) #RC-100-170 (Neon greer\) Tuned Port Tubes T h as e att raci iva. pr ef o rmed lu ned pons allow tha bad^ pressure ra- diated ffom the roar of iKe woofer 10 reintoroe the sound leve-F in tront. Made ol biacK pUtStio. Fainous Maker 3-1/2" Speaker Pair 49' /Ft, U f Price P«rt LjengLh Diamater {19) tlO^up) 1-3/4- .^0 .37 1 7/Q" .60 .55 sr T .65 ,59 «RG^260^23 r 2 m- 40 .37 *RC-260-324 5" zm* .00 .55 iRC'260^26 T 2-7/S' .52 #RC-26(KJ27 3-7/8' .58 ,53 «RC-£60-328 6- 37/e* M No nnlKEng for quantity prFcing, Duaicona 3-1/2" sp&aXer pair for upgrading stodt dash speakers. Graphite fiber composilB woofer con a provides a smooJh extended response at a!l power ^vefs. The high tiequency radiator (whizzar) takes over f rom the woofer at &,000 Kz and gfeaily extends the response pasi 20 KHz. Strontium terrrte magnej. 3^'4" high temperature voice coll Impedance: 4 ohm. Power handling capability: 2B watis continuous. 70 wans peak. Trequency /a&por^a: 120- 21.0tXJHz- Equipped v^th dusi screen. Wade in the U.S. by a coorpany wt;h over 40 yaars experience in ihe auto sounci nv^rKat. ^ . --|gg #RC-26 5-275 ^ ■ d Pair $19' Subwooferlnput/Oulput Terminal This recessed lermina! pane! has inputs for right and lo!t channaSs as wo 1 1 as outputs for right and Eeft channels to roure (o yo u r s atett^e sp eakers. GreaitysimpMies SubwooS&r hooK-up. Outside dimons ions: 3-7/S" 5-3/r. #RC-260-3CJ8 (1-9) if C Parts //t^press 340 E. First St.. DayJon. Ohio 45402 Local: 1-513^222-0173 FAX: 513 222^644 ' 30 day money back guaranty - S20.00 minimum order < We accept Mastercard, Visa, Oiscovar, and C. O, D, orderSr * 24 hour shipping - Shaping charge - tJPS Chan rate + Si ,00 (S3 .50 minimum charge) * IHour^ 830 ani - 7:00 pm EST, A^onday - Friday - 9:00 am - 2:00 pm Saiurday. Mail ordor customers, plaaso call for shipping est I mate on ordors exceeding 5 ftjs. ■ Foreign dos) I nation customers pEaase send S5D0 U.S. lunds for catalog postage - CALL TOLL FREE 1-800-338-0531 $3^ (10-up) FREE CATALOG CIRCLE 56 ON FREE INFORMATION CARD RECEIVING TUBES OVER 3Q00 TYPES iN STOCK! Also hard-lo^ind transformers, capaci- tors and parls for lube equEpment. Send S2.00 for our 32 psge catalog, ANTIQUE ELECTRONIC SUPPLY 6221 S. Waple Ave.'Tempe, A2 e5283*602-S20'S^i 1 GAMBLING: build miniaturo computer-clock rou- telle wheels, play perfect blackjack —Z- BO based; software available. For delatled plans and info send S15.0D to G.R. ENTERPRISES, PO box 424. Portland. OR 97207, ZAPPER! electronic (un. simple and Enexpensiv©. battery powered. Plans $2.00 to: PAR, 417 Asso- dated. Suite A-313. Brea. CA 92621. PROJECTION TV,„ Convert your TV to project a 7-fooi picture ,. Easy!... Resulls comparable lo S2, 500.00 projectors... Plans and lens $29.95... Professional systems availabEe,,, Illustrated cata- log free„, MACROCOMA, ISGF Main Street, Washington Crossing, PA 18977.., Credilcard or- ders 24firs. 1 (SOO) 955-3979. CABLE TV CONVERTERS with 2 year warranties. Scientific Atlanta — Tocom — Jerrold BS80 & 8590's. Test modules for Star Comm 6 & 7's. All Tocoms and Scientific Atlanta. (712) 323-9445. SATELLITE TV FREE catalog — Lowest prices worldwide. Save 40 — 60%. Systems, upgrades, parts, all major brands factory fresh and warranted. SKYVISION, 1012 Frontier Fergus Falls. MN 56537, 1 [800) 334-64S5. CABLE TV "BOXES" Converters-Descramblers Remote Controls-Accessorfes * Giiaranteed Best Prices* * 1 Year Warranty - C.O.D.'s * it Immediate Shipping* ★ FREE CATALOG * Call or Writ* NAS/TRANS-WORLD CABLE CO. 3958 North Lake Bfvd. • Suit^ 255 Uke Park, Florida 33403 1-600^42-9333 1-800-848-3997 SATELLITE TV — Do it yourself — systems. Up- grades. Parts. Major brands discounied 40% — 60%, We'll boat everyone's price. L. J.H. INC, call Urry (609) 596-0656. CABLE TV Secrets — the outJaw publication the cable companies tried to ban. HBO. Movie Chan- nel, Showtime, descramblers. convorters, etc. Suppliers list included. S9.95 CABLE FACTS, Box 711-R, Paiaskala, OH 43062. Q DESCRAMBLERS CABLE T.V. EQUIPMENT Wholfl Sa'^ Prlcmg For: JerroW. Scienlitic ASfanta, p:onsor, Tocom, Zoni'h, Oak » Baso Band, Etc / Lowest Pflco« Guaranteed V Froo Catalog ORDERS CALL 1^QOO-e35-23aoy402-3ai-322a Or Write MULII-VISIOH ELECTRONICS &V. 2730. Snulh 1?3rd Ct, #126 QmBhii, NE^ 6atJ4 DESCIiAMBLERS CABLE TV EQUIPMENT CALL TOD. FREE 1-800-228-7404 osammtn PROon 30 DJV MOW/ BACK OWpf voj won tw Mr HOB M cm VMEAHIB VVE CARR/ AU MAJOR BUWS BEST PRICE BEST THE COWMECnOH fOfi t/Ca WFCfiMWlON OJLL Ofi WtHTE 1-512-250-5031 *xff pg. m Mmm tdou jijst ANTIQUE RADIO CLASSIFIED Free Sample! pVxid^, Antfque Radio's /^i^j^^^^i/^^ Largest Circu'-ation Monthly. [^_©J{| ° M Articles. Ads & Classifieds. ilL^:^tli 6-Monih Trial: S15. VYr: S27 (S40-1st Class). A.R.C., P.O. Box B02-L9. Carlisle. MA 01741 MRRK V €L€CTRONICS, INC. Competitive Pricing * Fast Shipping Since 1985 \Htkr-m-%2Vmm{QfiBT^ only) OUTSIDE CA Vfl00-4Z3'FIVE (Orders only) ORDER BY FAX (213) aa&^6BBS CATALOG & mFDRMATiQN (213)8884988 A i n di cates the level ot d i M ic ul ty i n I ho a ssemlj I i n g o f ou r Prod u ct s . A Beginn e r A A I nterm ediate AAA Adva rrced * Fully Assemble d 5? TA-477 V^'-^r ^, I ,. ,, TA-1500 Special offer will be given to the purchase of AmplHier + Metal Cabinet + Power Transformer! 3fi00, ^ AMfLiFJEES MlSCIUJUtEDUS MODEL TAJJ™1K2 TA-SOO Tfi t5(J0 TA-3&D0 sum Mblti PufBose W-rodJy iMjppy Bmritiii Wi^J.Jmg U*rcn etc KJenflfjccf Ji'iVCli1.$''^'MJinf&rt(tMHWJ Anp A A Jflw Hglti.Pu I [MXne Single Cha^inetJirniJ A Wfi * hW Skren Pni' :' P^si^ftiai a Wi":rEi*4t DCfftfl*!! A MXt>C O'jjrtz [>tc^ji Clo:)! A Scund .■ Tisjcn Cgntrol &*it£h A intrarf^ Remcdc C^nrol Uml \ H-ti^ \ A A A ^f/Datlf/tlWiifAA 3i. .rDigilarP^I Meier A SO Step& Bit / Dot Aud^q ini"WA 1 A- e07l 8?ijauE5Cf.fncciDic-flj!jnr"*.M? rft.i?ov^j . K54>ri RevSlSf -Stfljli Vd Corfl i M TA 'A J7; TA lOOW TA.IJOW?] A'pi n«*K>f - Dji\ V5i Cwji I. ■ . ' i V " .'n ■ = ia ?™ i ??03 ?1.15 23.00 19.46 i65 0O 26 20 35 00 33 A1 « t4 17.00 TR-3S5A TTl-35.€e 0 i&v5ARegt,i3:ecl r-l 3A Reoulajfi J L' (JL50V3A Ffcguliled i::: ■ i < ICrriff'i A : L-iiti nlcrnifTI A , CJSeS x brnipri A A £1565 15 65 IE 75 S21 76 21 76 23 bh iUmi CAB tWETS WITH ALUMfHU W PAKEt. HIOOEL If iVr P MATCH IMG 1G-I?r3 3" 12' 7- TA230CI. TAvtV/A. TA 7?DD IG-I6fi4 * 16' &' IA-323A.TA37^A 1A7?ffif IG 19^4 4 1^ 11<.^ TA AOi; TA i;OMK? TA^MK2,1A TOOOA 1G.192S b iA^;7.lA «0 M<7 TA tMO.lA-TMOA TA3S00 PRICE .S?3a5 »5Q 38 01 30^ POWER rRAMSFORMfHS SM J3 3' M'jin Furiiiionaf Led 0PM (w.'Aas i^m CiSej AA. . SM-Ja di., Hi Pf«£i'iisr.DPM A*A SM-JflA 4 1 V Hi PjftL^iDn D P W [w.'AES pl^SEit A A A . , Zlji-i^ 3 ' . ^^ul]l T i|[M;l4|^l ICO P.UI P. 1 ivi'tkMd F gnttion) A A [lU-tOO 1 SOMC Uf^i:^ I [fquermy CcunlerAAA S34 ^0 . 3a 00 4130 3«0Q 7»0C 46 00 4450 90 00 OOS 006 DESC8IPTIDN * 2 EA tL^ 3ff; 2 %f> 3fiV 1. 2 3A 4f[)gra!niiwg. and kJIs mora. Out besiyei.OniySiS.gs Oifier fill dii- fefent) HJttions 1 99 1 . 1 989, Volume One (Basic Si 5,95 each MCS Hiriddook S-9 95. SjtEiWfl system? undp $KH S 1 2 55.. Any I'SI^ 9* or 96 Vjdflo 95 Stfim^ing NfWl MOnJtlty i^i ^^fr Sample %3 A3 cJ^iOaSl VCR tapes by college instructor covering elec- tronic topics. Send for free demo $3.50 P&H PO 292. Fort Mill, SC 29715. NEW book, Gelling Started in Wuciear Physics. Hasy to foJIow with ilEustrative footnoles and ad- vanced praciical procedures. $19.95, FARAH FARAH, PO Box 2464, Sarnia. Ontario. N7T 7Tt Canada, FREE CATALOG! 1-800-648-7938 JERROLD HAMLIN OAK ETC CABLE TV • SpQcml Dsaier Priciest • Compare oitr RBtaii PtiC6Sf • Quaranteed Prices & Warmntiesf • Ofders Shippe<3 fmm&diafefyt REPUBLIC CABLE PRODUCTS, INC. □ 4080 Paradise Rd. #15, DeplRE292rn 3 Las Vegas, NV 89tOd r*rJ For all other infomiation (702) 362-9028 BUSINESS OPPORTUNmES YOUR own radio stationi Licensed/unlicensed AM, FM, TV. cable. Information $1.00. BROAD- CASTING, Box 130-F2, Paradise. CA 95967. LET the government finance your smali business. Grants loans to 3500,000. Free recorded mes- sage: (707) 449-8600. (KSt), EASY work! Excellent pay! Assemble products at home. Call loll free 1 (&00) 467-5566 Ext, 5192, MAKE S$S! Become an American electrontcs dealer! Prolit opportunities since 1965 Call SCOTT PRUETT, 1 (300) 672-1373. HOME assembly work availabtef Guaranteed easy money? Free details! HOMEWORK-R, Box 520. Danville. NH 03819. SNOW? Thrivrnq. fuily equipped, audio-video re- pair shop. $130 K+ this year! Proven 40% + gross last three years. S70,000.00 cash AUDIOTECH, 256 'B North Highway 101, Encinilas, CA 92024. FAX (619) 944 0345, Phone (619) 944-9048. MONEYMAKERS! Easy! One man CRT rebuild- inq machinery S6,900.00 rebuilt. $15,900.00 new. Cftr. 1909 Louise, Crystal ake, IL 60014. (815) 459^0666 Fax (015) 477-7013, LEGITIMATE $$S opportunity SSS weekEy oDm- plete fejjori $19,00. DME* 1317 N San Fernando #325. Dept. 02W4, Burbank. CA 91504. CABLE TV DESCRAHBLERS ! CABLE KINGDOM 1 ScrsmEFlirtg Newt, ^S52 Hertel Ave., *JEROLD* *OAK* *HAMLIN* ^ZENITH* *PrONEER:^ ^SCIENTIFIC ATLANTA* IN STOCK 6 MONTH WARRANTY 1 UE SHIP COD ABSOLTLEY LOWEST WHOLESALE/RETAIL PRICES! J ,P . VIDEO 1470 OLD COUNTRY RD SUITE 315 PLAINVIEW, NY 11803 NO N_Y. SALES CALL NOW! 1 (800) 950-9145 EASY ORDER 1-800-582-4044 EASY FAX 1-800-582-1255 Js. TRIPP LITE - PRECfSlON REGULATED DC POWER SUPPLIES ACTIVE COMPONENTS Complete Line of DC Power Supplies to Convert 120Vac to IS.SVdc ±0.5Vdc. Standard Features Include: •Solid slatG ;n leg rated circuit provides excellent regulation -Outpul vollage maintained up to 95% of no bad value *High qualtty liHering for low noise operation •Heavy duty power transformer for complete line isolation -On.' Off indicator light and rugged on/off switch on faceplate •3 conducto' grounded cord on 1 0 Amp and laj-ger models •Current limiling electronic foidback for autc overcurrent protectron Tripp Lite DC Power Supplies Are Designed For RBiiabflity and Superior Performance. PR25 OLder_# Pfl4.5 PH7 PR15 PR25 PR40 PR60 32.95 44.95 64.95 S9,95 125,95 179.95 249.95 ICS' (amps) 4.5.. 7.. 10.. 15. 25. 40. 60. Continuous .Duty (am ps) F usin g BJpple Voya ge HKW xP_iLnche sl Weight . ..3. Internal 0.1 Voll Max ..3.125 x 4.75 x 8.25 5 lbs. ,.5 Cha&SES Mount ... 0.15 Volt Max 3.75 x 6.5 X 7.5 7 lbs. . J.5 Chassis Mount 0.15 Volt Max. ..12 Ctiassis Mount 0.15 Volt Max. .,20 Chassis Mount 0.15 VoIE Max. ...32 Chassis Mount 0.15 Volt Max.. ..48 Chassis Mount 0.15 Volt Max.. ..4,5x6.625x 7.625 10 lbs. ....4.75x7.5x8.25 131bS. .5.125 X 12,5 X 10.5 20 lbs. 7.25 X 12.5 X 10.... ...26 lbs. e.5x1Z.5 5f10 29 lbs. Mnlermitlanl Communications Duly (50% Duly Cycle) SOLDERLESS PROTOTYPING BOARDS SB830 Features ■Color coordinates for easy recognition •Insenion wire: 20 29 AWG (0.3-0.8 mmj ■Over 10,000 insertion cycles 'Accepts all standard components I SB16S0 SB2390 MICROS Order # Price 6342 6.95 6502 2.95 6522A 3.75 SeSV..... ....,1.75 6845 2.45 8OB0A 2.75 SOSSA 2.95 a086 4.45 8088 4.25 &237A5 4.15 B250 5.75 8251 A 2.25 82S3-S 2.25 S255A& 2.75 8275. 18.95 STATIC RAMS Order U P rice 2101,,,.,... .1.65 2114L25 1.39 2147-3 3.75 6116LP3 2.75 6116-3 2,25 6264LP1D 4.95 6264LP1S 3.95 6264-10 4.75 6264^15 3.75 62256LP10.....6.75 62256LP15 6.25 6281 2BLP8... 34.95 62S12BLPI0 32,95 Order MK4027N2 4116^20 4416-12 4164-10 4164-15 4164-20 41464-12 41256-80 41256-12 51258-80 514256-10 514258-80 511000^0 511000- 10 511001- 80 Order # DRAMS Prtce .75.. .85.. 2.95.. 1.95.. 1-55.. 1.25.. 2.75.. Desc, 4x1 ....16x1 16x4 .,..64x1 ...64x1 ...64x1 .64x4 2.75 256x1 2.15 256x1 4.95 256x1 6.95 256x4 9.9S 256x4 7.25 IMxl 6.95 iMxl 8,25 IMxl EPROMS Prtce 2708 2716 2732 2732A25 2732845 2764-25 2764 A25 27C64A15 27128A25 27256-25 27C512-15 27C010-15 27C020O5 4.75 25V 3.45 2SV 3.95 ,,25V 3.45 . .„,.,.. .21V 4.25 12.5V 3.75 21V 3.25 ...12.5V 3.95 ....12,5V 3.95 12.5V 4.75 12.6V 6.95 12,5V 9.95 „.,12.5V 24.95 12.5V Price Price Dimensions (m.) Dist. Dist. Terminal Termir>al Binding Order # ^9 10^. Lx WitH SUijiS PoinU Strips Points Posts SB200 2.99 2.49 6.5x0.37x0,4 2 100x2 0 0 0 SB400 4.89 4.39 3.3x2.2x0.4 2 100 1 300 0 SB530 S.4S 4.95 6.5x 1,4x0.4 0 0 1 630 0 SB830 6.49 S.99 6.5x2.2x0,4 2 200 1 630 0 SB1360 12.49 11.99 B.5x3.9x 1.2 1 100 2 1,260 2 SB166D 17.45 16.95 0.5x5.1 X 1.2 4 400 2 1.260 3 SB23go 22,49 21.49 9.1 X6.9K 1.2 5 500 3 1,890 4 SB3220 31,49 30,19 9.5 x8. 3 X 1.2 700 4 2,520 4 LINEAR Order Jif Price MAX232CPE^4.55 LM3tlN .49 LINEAR Order # Price Description^ C A3 1 6 1 E 1 .95 b e cQd e r Drive r CA3162E 6.25 Converter LM324N . .35 LM339N .39 LM555Cri . .29 LM741CN .29 LMl48er^ .45 LM1489N 45 70 LOS .35 . . .5V Pas Rq^ m %t 7805K 1.25 5V Pqg Rog. T0 3 7805T .45 5V Pos. Reg TO 220 781 2T .45 SV Pos. Reg TO 220 7 9 LOS .29 ..SV Neg. Reg 10-92 7905T .49 5V hJeg. Reg TO [MEMORY MODULES-SIMMS^ Order # Price Organiz aiion " 262 J 44x9...... 1 .048,576x9 ... 4,194.304x9. 256x9-80 19.95 1<9-&D 57.00 4x9-80 210.00 Speed ..BOns „,80ns ...,80ns ZILOG DATABOOKS* ZdO CPU Technical Manual This 33B page manual contain.s tlie afcMitecture. pm description, Mniing, instruction set. insiruclion dHsqripiJon, tnterrtipl response and hardware/soHware irnplorn&ntation exarnpies of the Z60 CPU. Order # Z29 9.95 ZSO CPU Technical Manual Weight: 1 lb. Intelligent Peripheral OontrolJers Over 700 pagsg of dala sheets, appltcatjon notes and technical (nlormation on Zi log's Jnieliiggrvl peripheral controllers. The part numbers contained m this booK are Z8400, ZS4C00. ZS4C01. Z84tOC10. Ze420 C20. Za430/C30. Z3440.'l/2-4, Za4C4 0/1/ 2/3/4, Z84C&0, Z8470 Z84CeO. Ze40n CI 1. Za40t3.^t5, Z04Cl3, Ct5. ZSOtaO, ZSOlSt and Z2fl0 Ofder# 22480 13.95 IntelligsntPeripheral Controllers... Weight: 2!bs. Datacom ICs Ov6r 70Q pages ol data sheets and other lechnioa! inlom^liOin on Zilog's Dala CorrntiunicationEi ^Cs. Parr numbers contained in rh]S book are the Zt6C30.'31^3<'3S'-50. Z5380. ZB323D, Z80C30, Z85C30, Z8030, Ze530, ZeOtei, ZB4013, 284015, Z84Ct3. Z84C15. 28440. Ze4C40 and ZBSCSO. Also induded ^tfe appjicalion notes. Order # 22503 1 3. 95 Datacom ICs ..Weigtrt: 2 Ifas. MicrocQntrollers Over 1300 p,igor, ol data sheets. appHcaUor^ notes aod tachnical infofmalion ort Zllog's microcontrollers. The part numbers contfiinod In this book arq Z8fi00/0t/02/03^04/-H/1 2/1 3/7t/01 /e2/91 , ZS0aO/Ol/2O.^22, 286COO/CO€/CDe/C09/Cl 0.d E/Cl 9'Ci^0/C2 1 /C27/C30/C40/CSO/Ce 1 .''C62/C 09/090/ C91/G93/C94.'C96.'C97, 2e6EOe/Eig/E2l/E30/E40, ZaaCOO, 286127. Ze6t3B. Z765A. Z33B0 and Z53C30, Order #Z8275 16.95 MicroconlrolJers ..Weigtit: 3Jl>s. * Books are not returnable. 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EPROM Programniei' Janteco Logic Probe • Max Frequency 80M1 1;; • Miciinnim dctectLtbJe pulse: lOns • ]20Ki2 input impedance ■ Max. supply vtiEtJge: -25V * IT I. threshold: (Lo)*0.«V lO.l V. (Hi) *2.3V ^.2V * CMOS threshoid; {U} 30% VCC ilO%. (Hi| 70 TMS25I6 S4.25 TMS2532A ....6.95 TMS2564 5.95 TMS2716.,. 5.95 !702A »„..,3.95 2708 »»„,.A75 2716, .„3.39 2716-I.,«, .„.„3.75 27C16 4.25 2732-... 4.95 2732A^20 4.49 2732A^25 3.49 2732A'45 2.95 27C32 4.75 2764-20 , S3.95 2764-25 ...5.75 2764A^2{) ,,,3.75 2764A-25 3.19 27C64^15.. 3.95 27C64-25.. 3.25 271280TP.. ...2.49 27128-20 .7.95 27128-25 7.75 27128A-15.. 4.95 27128A-20 4.49 27128A-25 .3.75 27C128-15.. 5.75 27C 128-25 7.95 JJliflp Part No. 272360TP 53.75 27256-15 5.49 27256-20 4,95 27256-25 »4,49 27C256-I5 5.95 27C256-20. 4.95 27C256-25,,. 4.25 2751201P 4.95 27512^20 6.75 27512-25 5,95 27C512-I5 ..6.75 27C5U-20 6,49 27C5I2-25 ...0,95 27C010-I5. .,9.95 68766^35 4,95 * Partial Listing * Over 4000 Electronic and Computer Components in Stock! CIRCLE 114 ON FREE INFORMATION CARD Selection & Competitive Prices Computer Upgrade Products and Electronic Components Upgrade your existing computer systefn! Jaifteco will help you ttpgrade easily and ecanomically Jameco SO 386SX Motherboard ■ KiMHz proccisingspt'td * R.iby niottiertvoard (S.V'xl.V) ' Zero nr one wjii itaie operaiion ► StLp|)0[)s up TO HMB IIAM * hurl 8()JS7SX/conipa[Lb]e mjLh coprocessor socket •AM! BiOS * Sin Ki bil ant! two S-bii eKpansion bui slots ■ OjiL'-ycMr Wn^franrv Fujitsu 101 -Key Enhanced Keyboord Wis kcybojrtl features 12 function keys, scp.ua (f turgor ami nuriikTii.' ki.'VN, • !HM f*C/X !VA 1" and cani[>3Lib!e caitipuurs • ALUOEti;i[iLMl|y swiccbes between XT or AT • [.!■'!) tiuikators for Nuin Ijock, Qps Lock, and ScroK Lock • i ac( i!c hicdback, ■ M J una I i[] eluded • Onc-ve^r Warrant' T JE351GSN „»S299.95 Conner IDE Herd Drives Thk strtcs (jf high'pcilorniancc Conner disk drives \% dciig;ied for large CP3000 4DMB 35 ' Low Frnfilc S249.95 CP300S4 HOMB 3.V'l.ow Prolllc 53*^9.95 CP30104 UOMH 3.5^ I Prorik%**S479.95 CP3204 2(miB 3.5^ HH S699.95 ADP20 16 bit Wmx Athpicr ,,$29.95 Mtuiy more Upgrade Products available! FKB4700 $79.95 Toshlbo 1.44MB 3,5" internal Floppy Disk Drive • IBM FOX J /AT and compatibles • Compaiible with DOS versions 3.3 m higher • InLlticies ill nccessan.' insulbrion hArdit^ijrf • 1 ,44\iB formaired higb dcnsiiy mmk • 720 KB fornutted low dcnslt)' mode - Size: fiH ?c K ^.911 (act ml drive siie) • O nc' \XA r M iTj Lifac [ u f cr's mmy 556KU , ..$99,95 Integrated Circuits* nai^ Hp. ■ m± 7400 , $,29 $.19 7402 , ,29 .19 7404 ,29 .19 7406,., 35 .25 7407 .35 .25 7408 ..„.. 35 .25 7410 ,..,....29 .19 7417 35 .25 7420 29 .19 7432,. 35 .25 7447 , ., .89 .79 7474 39 .29 7476 45 .35 7486 , , .45 .35 7489 .....2.95 2.75 7490 59 ,49 74121 , .49 ..39 74192 , 79 .69 74193 .79 .69 Linear ICs* r^rt No. 1-9 in* TL082CP $.59 $.49 LM317T .,..65 .55 LM324N .35 .29 LM336Z„.,.,..,......,...1.05 .95 LM339N 59 35 NE555V , 29 ,25 LAi556N „„., ,49 .39 bM723CN,., , .49 .39 UM741CN .29 .25 L\fl458N 35 ,29 LM148SN 45 .39 LM1489N 45 .39 ULN2003A. 69 .59 LM3914N.., .J. 95 1.75 NE5532,.. .........1.19 1.09 78051 ..45 .41 7S12T 45 .41 * C6tli for it mnpha- Imni &f fCs Dynamic KAMs 4164-100,.. 4164-120.., 4164^150.., 41256-60., 41256-80.. 41256-100 ...1 41256-120 ...1 41256-150 ...1 5110OOP-8O... 511000P-10. Dciicri j>U< lOUii^, 64Ks 1 \20tn, 64K X 1 150n?i, 64K X I GOm. 256K x I 80ns. 256 K x 1 00ns. 256K x I 20ns. 2%K X I 50n5> 256K x 1 80ns. 1MB X I 1 00ns, 1MB X 1 $1.89 1.69 L49 2,49 2.19 1,95 1.79 L69 5.99 5,49 Miscelloneous Components* Potentiometers Vilues av^iilable (insert ohms itito apace rr],vkfd "XX"): IK, 5K, lOK. ^[)K, 50K, lOOK. [MHCi 43PXX 3/4 Wm, 1 5 Turn ..... $.99 63PXX !/2\V;itE, I Turn 89 Transistors And Diodes PN2222 S.12 PN2907 .12 1 N4004 2N2222A 1N4735 2N3904 .10 .25 .25 .12 1N751 C106B1 2N4401 1N4148 2N3055 IN270 $,15 ,65 .15 ,07 ,69 .25 Connectors Pirt Nffl. DB25P Mulf. 25-pirt I'eniidtr, 2 5 -pin S.65 DB25S .75 DU25H H(>od .39 DB25MH Mc^,t] Hood LEDs 135 XC209R T!.(Red) S,14 XC556G T! 3/4. (Grct-n) .16 XC556R ri 3/4. (Red) .12 XC556Y Tl 3/4, (Yellow) .16 IC Sockets 8LP 14LP 16LP 24LP 28LP 4QLP $.10 .11 .12 .19 *22 .28 8WW 1 4 WW 16WW 24WW 40WW $.49 .69 .79 L15 1.39 1.89 and HfitJfT iHug 24-Hour Toll-Free Order Hotline: 1*800*831-4242 Call or Wrirc for a FREE 90-Page 1992 Catalog! $30-00 Minimum Order * Data Sheets - 5 OC each Switches JMT 1 23 Sr-DT. On-Oii ( Tijgg Ec) $1.15 206-8 SPST. Ifi-pin fDlP) . 1.09 MPCOl SPOT. On -Off On rroggEL') L19 MS102 SPST. MontcriTiiy (Puih-Bittfon) 39 *AtUhwnai coTnpQnems itmikhlf J AMECO ELECTRONIC COMPONENTS COMPUTER PRODUCTS 1355 Shorcwajf Road Bdmuni, CA 94002 FAX: I •800*237 6948 BBS Suppon: 415-637-9025 Intcrnattond Sals • Customer Service • TccKnical Assistance • Ciralit Department • All Other Inquiries: 415-592.8097 • 7AM - 5rM f.SX ^0m2j4mm J/92 CA [Ic^iibih Ask! 7,2^%. 7J5%flrS.-35%53J«Tix [ Shipping Kandlingand insurant are ^diiftional. Tcrmj; Pritci subjtfi to thjngc ^iihouc notice, E[fms vubjctE [u jvjiljhiEii;^ ,ind prior i2k> Complete liM. ol' tcrciju'wjjrjntiei h jrvjiUble upon fcifUCilK CIRCLE 114 ON FREE INFORMATION CARD AMAZING * "^"^ PRODUCTS and KITS Space Ships in HG WeFis mr onh« Wortds? WYSTERY Levitating Device ObjecEs fEoai on sir and move to ths touch, Defies gravity! Amazing gift, conve'sarion piece, magic trick or great sdentiftc pro-ect. AffTIK Easy-Ass V Kit FEansSt 9.50 3 MILE FM Wireless Microphone! Crystal clear, uFtra-sensitive pickup Eransmils voices, sounds to an/ FM radio, For security, rnomtorir>g children, invalids. Be Ihe local DJ' MVP1 Plans S7.(M WVPlKKIt'Plans.. $39.50 3 MILE Telephone Transmitter! AuEomaticaily transmits 2 sales of phone conversaiion Eo any FM radio, Tunabte, easy- assembly PC board. Operates only when phon$ is in use, VWPM7 Plans $7,00 VWPMK7 Kit/Plans S39,50 TV & FM Joker/Jammer PcKJtet Size devtce leis you refnotily disrupt TV or racto reception. Great gag! 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Ctass Ilia item VRL3KM 3mw Laser Kit . . . 599,50 VRLSKM 5m w Laser Kit $119 ^0 MORE Laser Kitsl LAS1KM Imw Laser, 632nm, HeNe Easy to Build Kit 569.50 LAS4KM 3mw Ver sion, Kit $99,50 lATOS Low Cost HeNe Laser Tubel .5m w Tube i Plans . . oniy S24.S0 0!^rer pans available separately. Great L ow B u dgel Science Projeci] Shocker Force Field ^Vehicle Electrifier Make band shock balJs. sbock wands elecEnfy objects, charge capacitors. Great pay back for those wise guys? SHK1KM Easy Assembly KttS24.50 llh|i|iiM with many more items! FREE with order, or send $1 P&H CABLE TV DESCRAIVIBLEBS ^ CONVERTERS'^ and ACCESSORIES. SAVE MONEY. Mif TRENT! PANASONIC, JERROLD, OAK, PIONEER, SCIENTIFIC ATLANTA AND MORE. LaVEST PRICES. FREE CATALOG. "cS'nT (800) 234-1006 PRINTED CIRCUIT BOARDS HAVE a requirement for your project or profes- sion? Small runs O.K. 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Full safes catalogs. Send 56.00 VLSI, 4960 Jasper Avenue North, lake Elmo, MN 55042. SI t s O LIJ 9 102 NEW LITERATURE continued from page 87 tions are described, along with some special modula- tron techniques. Radio fre- quencies, propagation, and Space communEcations are covered. Almost half of the book focuses on construction and rrfamtenance of ham equipment, and getting on the air. It provides practical advice about construction techniques, test equip- mentn measurements, trou- bleshooting and repair. Instructions are provided for building your own power supplies; audio and video equipment; modems; HR VHP. UHR and microwave equipment: antennas; and accessories. PC board patterns are included, as are parts lists. Tips are pro* vided about how to assem- ble a station, monitoring and direction finding, and coping with interference. EQUIPMENT, TOOLS & SUP- PLIES FOR ELECTRONIC MAINTENANCE & SERVICE 1991-1992; from Print Prorf- ycts International, 8931 Braokville Road, Silver Spring, MD 20910; Phone: 800-638-2020; Fax: 800-545-0058; $2.00. The 64 pages of this cat- alog are filled with products nr. ToCi.4 A CIRCLE .^5 ON FREE INFORMATION CARD from major manufacturers, including power-protection gear from Triplett; test equipment from Beckman, Leader. B&K, Soar. Global Specialties. Hitachi, Ken- wood, Simpson, and Vec- tor Viz; Pace soldering/ desofdering and surface- mount rework and repair equipment; programmers from Logical C.S.T. and American Reiiance; and Print s own custom tool kits and cases. New to this cat- alog are service monitors and radio test equipment from Helper; Landmark PC-troubleshooting gear; AEMC test equipment and power-demand analyzers; Ungar soldering irons, Fieldpiece field-service equipment; static detec- tion meters from Staticide; and spectrum analyzers from Avcom, Penntek and B&K. R,E ELECTRONICS 100 10 C^inoga Ave , Urnl 6-3 Chiitsworth, CA 9t3n LASER DIODES STOCK Jf MFG. WAVE- LENGTH OUTPUT POWER OPER. cum. OPER. VOLT, 1-24 25-99 100+ LS922D TOSHIBA 6G0nm 3 mW 85 mA 2.5 V 123.09 123.49 111.14 LS920Q TOSHIBA GTOnm 3 mW fiS mA 2.3 V 49.39 47.99 43.19 LS9201 TOSHIBA 670nm 5 mW SO mA 2,4 V 5&.99 56.99 51-29 LS9211 TOSHIBA G70nm 5 mW 50 mA 2.3 V 65.49 59.34 L£92t5 TOSHIBA 670nm 10 mW 45 mA 2.4 V 109.99 1&4.49 9^.04 LS32CK3 670nm 3 mW 85 mA 2:2 V 55,99 5699 51-29 LS022 SHARP 7&0nm SmW 65 mA 1J5 V 19.99 18.99 17.09 SB10&3 PHILLIPS 820[im 10 mW 90 mA 2,2 V 10.99 10.44 9.40 WAO II PROGRAMMABLE ROBOTIC KIT ■ < ) • Power Source - 3 AA batteries (not incluCea) DESCRIPTION M V 9e 1 WAO 1! programmabte RoboUc Kit WilAP ItnmfacB Ki\ For Apple H iSB. ih Thp pon mochanjsm irt- GlLiCJecl wilh Ihe robot allows it Id draw. In addilion to drawing siMight linea. i! can also accy- rale I y draw csrcles. and even draw out words and short phrases WAO II cornes with la© X 4 bits RAM and 2K ROM, iind is programmed direclly via Iho koypn(i allgchcd to it. With kts b uiiM n CO n nector po n , WAO fl (3 ready lo communicaJe wjth /our compuler. Wilh the OpIiOnj^l intcH^CE^ "kil. you can cor^nccl WAO II lo an Apple II, Me, or ' h com puter. Edit i ng and lrcin$lonrhg Ol any mflvetnenl program, as well as saving^ and loading a program can be performed by the mlerfaoe kit. Th© kil incEudes soflware, cat>re, card, and instructions The programming language is BASIC. 1-9 10-24 2S+ SINCE 1983 — YOUR I.C. SOURCE — AND MUCH MORE!! NO SHIPPING CHARGES ON PRE-PAID ORDERS!* NO CREDIT CARD SURCHARGE! SCHOOL P.O.'s WELCOME! PROTOBOARD DESIGN STATION * Variabje DC oulpul -5 - to ' 15 VDC p O.Ej amp. ripple - 5 fdV * Frequericy generator ircquency rjinge: 0 1 Hi lo 100 KHz in 6 ranges QUtpul vol! ago; 0 to i 10V {20 Vp-p) outpui impedance: ©00 (except TTL) output current: 10mA mas., short circuit protected output wavarorms sma. square, triarvae, TTL Sine wave: distortion 3% (10 Hz to TOO KHz) TTL pulse, nse and fall time 25niS dnvo 20 TTL loads Square wave: ri$eand fall lime ± 1.5 5 * Logic Indicalors a LED's. active higb, 1.4 vgit (nominal) Ihrcshotd, inputs protected to i 20 volts * Debounced pu»hbyLlon$ (pu:l$er$} 2 push-button ope rated, open-collector output pulsers, each with 1 normally- open, 1 normally-dosed output. Each otJiput can ^ink up to 250 mA • Polenliometers 1 - IK , 1 10K .all leads available and uncomrrntted « BHO corxncctors 2 BNC connectors pin available and uncommitted shell connflcted lo ground • Speaker 0 25 W, 8 ii • Rreadboardlrtg ares 2520 uncommitted tic points • Dimensions 1 1.5'" long X 15" wdfl x hsgh * Input 3 wire AC Nna input (1 17 V, 60 Hz typical) • Weighl 7 lbs. 79.99 75.99 37.99 63.39 34.19 I ThEj total design workstation - including e;ch ass^SmOiy islron loot dtsjgfiecl ttjr low volume. Fnass Tefmindtion oi v^ngu^ EI3C tdfuiK^lors ort Thai • A33CT'i^y 5^!e & ;lar4ldi a t!att-n iriclLided • BtSSS p!i3lif & pJak^n may IX' rotated for masurium • ESasc plales & cuTtin'ri acc«- wnfiout any tools rcmj.rtKj • .Addition.ai ficctssonca b&\airo*ii gjiin GaAtAa laMf. Tnis colli rrtalOf ptft^ iS^iv^rs n tAitximvirn CVf ouTpul poiwf ol 2-^ mW al SGO nnft Tha Dpcalino vocaJ ccad or wrrtc s/i.k^ n.-n. it ■$ lufipiiid complflW mm te*te lot conn«i^iOfi to A tC power supply from 3 to 5.56 V. TrfcOi>gh pr?-se( lo pr^jduqE^ a p^ritil^ boarn. \kc focat length c^m Ttadiiy E?e wJiv^ted; tq f^jcus irw bnarn tossfK?!. Stiirdy. sm.alil And ^If-cort^ lisir^cdJne LD W135 is a prtrcision dovito doslijnfld tor a wide ^ango Of npplioati^?r>^. 0.64" njiam. x 2" lO'lTJ. 1-9 10-24 254- STOCK # DESCRIPTION V9 a&+ COLUMATtNG LEHS DUAL MODE LASER POINTER This economics^ cCilinTuHm^j kjTis assembiy consists of a black anoaizcd a1yinirii.im bdmel that acts eis a TUs^i %Tt\k and a glass *ns wnti a ftfoir poinl ol 7.6 rnmL t^csJti'n^a lo M SlsndafCE 9fr.m J^^r diixJ*?* iriis ££scittb[y will r.t air tfxf above taser d;£jdLi. Simffly pLjce diCKSe *T the lefK fljsern- ^^^^^ piVr al3^L^3l EKsrit to deai^fti t^^yiX. [acus. then Stit vM-^n adhciive f 4:^73 1.0Mi;j5-.5 LOMlSS-l New a3imline i.i&e^ rK>mi«f uniy r | LDM135'3 in di.inn?lcir I &• lan^ arid weighs under 2 QZ . 570 firri lySa inan 1 £,witcr)e3. ckt* tc^ caniirii,j(Ha mt}6s, ard D*W lOf pi>JM) inOOD fri?cl ctol ^tasTies >apfCl^> ? AAA b-iltctrei urafranty .is mWiasBF Dlcnio Moduh 2 mVf Laser D>adc KfDftult) 3 mW Lflspr Dftxiv 179.99 169 99 199.99 209 99 170.99 1^^9 170.99 179.54 He-He TUBES Ooal Mode t,os^f PQi(^!er 1S9 90 liTJ.^g 1-9 1t>-24 2^ LSLENS Co{inth^t)/\a i-Cns As^cmbW 24.99 23.74 2T.37 POWER SUPPLY • Input: 1l6,'a30V ' Outpui; +&v(u' 3.7§A _ *l2v'<5:' 1 &A ■ Sue. 7" L » W K ^'T' H ROBOTIC ARM KIT STOCK ft PS1003 PRICE $19.99 flfltioEs tf^cre once cprvlifitHl to scitinctj fiction Hiovrc*. Yodny. wnfitnpr thuy're licrlormirig dAnflcyrotis tasks or pulling tDgiS'thQr complQK proiJiicth, njbolica are finding ifioiT w^iy irilo morp and more industriea. Thu RotjaHc Arrn Kn is an tiducalionnl kit lhat tt^^hus tjascc rotv^tic Eirm iijniinnieniaii aswcii a£ iG&ling your ovwn niijtor tkills. COmmLmJ >i fj perlLirrrv simpler Ins^s Nftw, tX^i/A ^nm Hc-Ne Jarser liibH nnfling froim .^Vi^ to 3n%W (OMr cNpicel. Perffeci fw hpbb/ais lof home projects. Because ol Hie vari«)y purchase. w& ca.'inol guarJtntc? SpKific outputs witl ije' i:iivailnibic si itrcKj: of ordsf. All yntis ft'i? piifw, tfiited and guafanteod Id lirnclipn a( ma nu la i; U:re spocificatioris 1-a 10-24 2&t AVOIDER ROBOT KIT STOCK i Y01 PRICE f\n ■nH.'lllrjcnf robot Ih^T iinows hf^iw lo iivoid tutdrvg waits. Tfiia robol em Its An mfra-r^d b^am whsc^ii d«liK:ts an obslacle in front g nd the n aulomalicaliy lurns le)( s.r\6 can' Initios oo. STOCK # PRICE S43.99 INTERNATIONAL ORDERS — (818) 341-8833 • TECHNICAL SUPPORT — (818) 341-8833 — ORDER LINE — (800) 824-3432 • FAX ORDERS — (818) 998-7975 IS.OO JWJNIMUI',^ ORDER • UPS BLUE, RED fl FEO£HAL EXPRESS SHJPPING AVAILABLE * OPEN MON FRI 3:D0 AM - 6:00 PM. SAT 1D:00 AM ■ 3:00 PM PDT • OA RESIDENTS ADD & : SALES TAX * CALL FOR QOANTlTY DISCOUNTS • CALL FOR FREE CATALOG (FOR 1ST CLASS DELIVERY OR CATALOGS DELIVEHEO OUTSIDE THE U.S, — SEND S2,00) • WE CARRY A COMPLETE LINE OF ELECTRONIC COMPONENTS 'NO SHJPPJNG CHARGES OM PRE-PAID ORDERS DELIVERED JN THE CONTINENTAL U.S. 3 103 CIRCLE 194 ON FREE INFORMATION CARD ggS KELVIi I 2 LIJ 9 d: JfEt WW DIGITAL MULTIMETERS B 1 00 SavlG 1 50 Basic* 2O0 Advan ccd OC VOLTAGE AC V(X r AttE DC COftRf tiT DJOOL lEST flATTEHV TEST 3 17 [>.gu LCD LOW PATTERV ACCtJnACV KELVIN 100 Ba&ic S-^ g 95 DC VOLTAGE AC VOtTA&e E5CCURR£MT HESISTAAtC^ CONTINUITY - OJOOE TEST TRANSISTOR i^fE SATTEHY TEST :n.?a.g.ticn LOWBATTERV AQCUi^ACY ■ KEL VtN 150 Baste i- S29,95 Protective Cases FOf M0(|«1t too, 1M. 200 '4J AC CURRt^T RESISTANCE CAPACITAf-CE CONTlNyiTV TcsJ ■ RLjif DiCDE T€ST TRANSISTOR \t LOW BAHERY ACCUPIACY - KEL vm 200 Asvancod ACDC VOLTAGE RAMGES ACDCCURREKT RANGES 5 FrtEOLSfflCY RANGES £ CAPACTTANCe RANGES LOGIC TEST CONTWU17V TCSTFflUuZffR DtOOE CHECK TRANSSIOH hFE TEST lEO TEST Vl FW YrjOODflAO DiSPtAV 3 l.l?D(GfTLCO ACCimACY 0 5-?. iMF^LOANCf 'I KBlvm PRO 400 $69.93 Case For Modd PiO 400 >9.*^ I ; : I j FEATUflES ■ ONE Die IT TRUE HEXADECIMAL OJSPLA^Y WtTH BUILT IN LOGIC (UEMORV, DECODER, DFllVdRS> FULL CHARACTERS ■ TWO kNt>£F^ENDENT CLOCKS - USER ADJUSTADLEFnEQUE^CV & DUTV CYCLES ■ BREADBOARD :SOQ PT PJ^GTO-TYPE AREA TWG POWER DlSTFIiaUTJON BU^ES (i3H0,VCCt ■ A BAT A BIT SWITCHES ■ MOUEnTARY PUSH BUTTON SWITCH (SPOT) ■ 4 LED DISPLAYS w IC DRIVERS a POWER SUPP[.¥^ WALL PLUG-IK TYPE, U.L LISTED ■ VOLTACE REO:+S VOLTS. SHORT CIR. OVERLOAD PROTECT ■ HOOK-UP WIRES ■ OOMPACT CJIRRVWO CASE ■ MSTRUCtlON IIAHUAL R)fl BEGimiER tO AOVANCCO USERS FREE COMPREHENSIVE TEACHER/STUDENT LAB MANUAL t/riinsT WirtuAl (ICQ Fq-il gives die:Lli;« PN2222 * .08 ea 600023 7805 vc^.Ti.iT.e flic ' ,36 SILICON CONTHOUED RECTIFJER JSjinilar w GE C106Cli4 0 AUP, TOOpiv 5000 14 ^ .89 ' .79 Stock No. Pq^I Conlicli ... yoURCOST 6B0093 0 500 ' 4.^ &a009Z 0 940 ' 5.*^ 68009B 2 1380 '11.'=^ 630100 4 2390 '22.^^ WIRE JUMPER KET ^^^S SfV 330209 140 Piece Sot „.' 47^ 330290 350 Pi{jco Set h.. * 7.'* Dura cell ' Eve ready 9V Alkaline Battery M.95ea ^U5 eaio* 9V Battery=^^ ^ SNAP a HOLDER \ _ Snap '.iSea *.lOooioo+ Holder *.20ea MOea lOO* IH-ilitiHjjjiilfi IC CLIPS r-*==^J^ SOLDER TVP6 I ' JUM SPRING LOADEC) 5i™;iiWa. COLOR COST 25* Qly 9«t04 BLACK * *65 ea * .50 <»4 RED *.65ca ^.50 IC TEST LEAD SET S COLOR CODED LEADS WITH UMAIiTflf nOOK^ Pi^OO AT ElOTtifHlTS. SEoc kNQ YOUR COST 5* Gtv 990&e *5.95 ca *4.95 ea BNC TEST CABLES 3Fr. HORN ALARM Loud PtnotntiriQScund | Stecv Mo. €40001 '.7Sea 9VDC^ *.69e3 iO*Oly DC MOTOR lor BOLAR ROflOTIC_j Stock No. e^zs'i I * .50 oa XENON STROB Stock No. TUBE 260050 '2,95 ea ^2.50 ea , 20* Qly TRIGGER COIL fot X«n«nSErDb« TutM Slack NO. 320037 ^1.25 ea 5 .89 ea 20+ Qly INFBARED LE IR Pajr. LED iniis and receivef Stock No. E&0O61 ^2,79 pa NEON LAMP Hti. Lena Laadi Sta^h No. S6Doa3 / , / M5oa //// '.12 6iMD0+ Qly PHOTO CELL CADMIUM SELENlOE Slock No. ^99 oa PHOTO CELL SULPHtOE ^99 (^a PUSH-BUTTON SWITCH PUSH-ON, PUSH-OFF StortNo 2r002l ^™ *.55ea SJ^ ^49 100+ Oty SUe-MJWIATURE MOMENTARY SWITCH StOClt No. 9g^30D2 '.35 ea ^ .28 ca. 100+ Oly MINIATURE TOGGLE SWITCH BiQ-tV No. 270034 ' .90 ea rypft' spsT ^ .79 . SOt Qty KEL VIN £LECTB£)MCS. ^ UALE TO M ALE toe k No. vo u R COST 3+ a ty 9?(Si0i '3.45 efl '2.95 1 CtRCLE HESPOl WRITE lor our WHOLESALE Pf /NSTOi ELCCTRDNIC COI I. TECHNOLOGY VISA \ WASTE nCARD ACCEPTED S20 MlNfMUM OROER MIMtMUM FREIGHTS^ KELVIi Electronics 10 Hub Drive, Melville, NY 11747 aRCLE ^m on free information carp Call: 1(800} 645-9212 1(516)756-1750 Fax 1(516) 756-1763 COURTEOUS SERVICE ' QUALITY PARTS • DISCOUNT PRICES • FAST SHIPPING "MAX" The Remote VCR Controller "MAX" allows j-ou To and control a sfngEe VCR from oJhor locaEions l^i ihe housfl. TfansfTiTs audio, vkJeo ftnd IR signals up !o too leoT Ihfough mlnl-aib!Q. Works on up to A televEsiona a) atimoH txjl a separate 'MAX" recede! is rebuked for each TV. Can a[&obe usAd with Dthi^r Miaiod contfollor davk^os such as CD pEa>'9rs or st^roos, Q9Cau$« it i$ harcWied. signal Iransmtssion is dea^ar thaJi more expsnslvo non-hardwired uniT&. fncludos iransmrr&rK recelvof. lOCf cabfa, hook- up cables and wall Iransformer. Th&se fisw unrTs of iglnfJI/ so3d for ovar Si 00.00. CAT* MAX $40.00 each 4 or more S3G.00 each WIRELESS REMOTE CONTROL FOR NINTENDO^ ATTENTION NINTENDO''' USEHSm GAME RICA "Fr&ftdom Connection" ™ Turns youi wired Nintendo^ cornnoS paddJe inio a romote conTfol unrt. hkar&d r emolo Irke Ehose used on TVs and VCR's efjninafas mossy wires. AHows pfa;^ers more mobility. J-hq players can use one remota uni: e^fcep) on garnet where they pjay simrurtan^usFy. Hn ihose ganV9S Iwo "Freedom Conoecttons" units are Toquiied. A weri-1 p-iistc box 1.91" X 3.ir XC.83S\ CAT#DMR-1 $3 50 each OPTO-SENSORS H1331 tJ -shaped opio with 0.125' gap batwean omm.ler and $ensof. 0.75" moyrtting ceniets. CATKOSU-11 2 for S 1.00 TRW/Oplron ft 0PBS447-a IR emtiEar/sensor pair in rpclangulaJ packag-e wilh 26' co^Df cod ad tead&. CAT* OSR-4 3 for St . 00 4 AMP Full Wave BRIDGE *RS40SL 4 Arrp 500 pW EpQ)fy packagOr ln-Liri« l4ads CAT* FWS-40S eacn Reehargab!^ Batteries SUB-C 2 PACK SSub-C niciisl -cadmium batCeriQS with Solder tabs. Connected in series. This slEe batler^ is iypica!ty lound in power tooEs, f afnote contrail models, alectric shavers and other home aj^pEcances. Each battery rrioasufes O.er diameter X 1,00" long. CAT* NCB-2C 13.50 per pjacK Standard JUMBO Diffused T V3/4 size {5 mm) RED CAT*LED-1 10 Id St. SO " too Tor SI 3.00 GREEN CAT*LED-2 10lorS2.00- IOC tor $17.00 YBLLOW CAT« LED-3 10 for $2,00 ■ too (Of Si 7. 00 FLASHtNG LED W/ bjilt In Hashing ctfcuit 5 vo!: operation. T 1-14 (Smrr:) RED Sl.OOoach CATiLED-^ to for S9. 50 GREEN Sl.OOoach CAT*LED-*C lOIOf S9.50 YELLOW $1.00 each CAT* LED-*y TO fof $9.50 LED HOLDER Two piece holder, CATJSHLED I0for6&«i RECHARGEABLE fi^TTER/ES NtckeJ-Cad AAAStZE SI. 50 each 1.2 volEs leo mAh CAT#NCB'AAA AAS!ZE $2,00 each 1^5 volts 5, CAT*DCTX'1£5W $4. SO each' 12 Vdc 200 ma. 2.1 mm D.C, powuj' piug with cafllsr nega- [jvft. CAT*DCTX-122 $3 00 each HEA T SINKCOMPOUND 14/3 LINE CORD 1 DIP RELAYS Mi-^lalu.'fl ReLa^T] With Pin Gor^tigLiialion To FjI t4 DIP. SVdc-S.RS.T. Gi Clare Jf PRWA-tA05S. Normally open roed refay. SOOohmcoil. (J.L. listed. Diode pJotoGted. CAT*DRLY'S7 S1.50oa:h 12VdC'S,RSJ. GoT-dosfl 946A-412 575 chmcoil. Sealed. InlfsmaJ daT^ing diod?. CAT*DRLY't2 31.25 each 24 Vdc - S.P.D.T Gl Clare U PRMA 1C24 2,150 ohm coil to vA sw!lcning ocwer. CAT* DRLY-tC24 $1.00 ea. 43VdC'S.P.aT Arona; irDSlE A DC4BV 5h750 ohm coil 2 amp contacts^ CAT* RLY-7Bfl $1.00 each G G Ef&cirontcs f 10 3109 ■ Foi offectivo translef of heat between components and hoat sinks. Z9 $iticone heat sink compound. CAT*H3C"1 S2,00 per 1 oj tube PHOTORESISTOR 1 .000 0 hms b rig hi light , tf)K &hTi3 dark. \\ 0.182" dia. X .OS'h'igh. 0.1S* kjng Wads. CAT*PHE-7 2forS1.00 100 for $45.00 ' 1000 for S400.00 SWITCHES Pushbutton Switch SMK Maiufacsuring 0.47" sc^uare black pushbutEon SPST normally open. 4 p.c. pins loj mourn- ing, (deal for low currcnr swjtcfiing applications. CAT* PB-23 5 for $1.00* too lor $15.00 RFl/EMI LINE FILTER Cofcom* 20 amp RFt^EMI genet' al purpose common -mode filter. Controls Ime-to-g round noise Srra!1 sue, tow leakage. 3.4^' X t.ie"X2.ei-. UL and CSA Hsted, CAT*|?R^20t $E5.50 HALL EFFECT SENSORS Micro£Witch#SS41 Tiny, so^sd slala switch j j reacts instantly to proximity of magnetic lialdr Operates at e:(tremely high Speeds, up to 1 00 tthz. Case siie: 0. 1 2* X O.ir x 0.06' thick 4.5 Vdc to 24 Vdc supply vodiage. tO ma, sink lype digctat output. Operating gauss - IS to 40, P C. teads. CAT*HESW-2 75c each 1 0 lor $6.50 ' too for $60.00 SURFACE MOUNT STYLE Sprag ue * UG!sr307 5LT Dperales on 4.5 - 24 Vo5s 1 1 I Can sink 10 ma. Wcih su. table output pulE up, can bo used directfy whh bi-polar or CWOS togic circuits. Espodaify su^ed lor electronic ooiv mulatJon in brush loss D.C. rriotors us- ing muHiple ring magnets. Very tirty surface mount package 0. 1 75" X 0.09'XO.Oe'Thidt CAT#HESW'S 2 for $1. CO too lor $45.00 £ A RGB QUAN Tt TIES A VAIL ABLE Highest Quality METAL CASSETTES Premium quaJily metaf tape sn G-CO styie cassettes (X or more pef side). One ol the line^t 'brand -name" tapes oo the marketn in dura&ki, dear ptastic t/an^pod mechanisms. Recorded and buFk erased, the record-protect tabs have been removed and therefore, heed to bo taped over 1o re- record, Audiophites will appfeciale the wkJe dy rmmic range o( the tape. 3f your caESotte tfeck has a 'meial" SetJing you wilf hear Ehedilforenco, A real bargain! GOmin. taoe - CAT* C-fiOOM SI. 25 each - tOlorSIO.OO CASSETTE STORAGE CASE Black, unbre^ab^o plaslic audk) casserte ^iiwagecasa. CAT*CBOX 5 for SI. 00 - 100 for SI 5.00 ORDER TOLL FREE 1-800-826-5432 FAX (818) 781-2653 • INFORMATION (818) 904-0524 Csl I Or Writ© FO r Our Minimum order $10.00 • All Orders Can Be Charged To Visa, Mastercard r- /-» n t Oiscovercard * Checks and Money Orders Accepted By Mail • Catihrnia, Add Fte& 64 Pa ge Cat a 1 0 g sates Tax ^ shipping And Handling $3.50 for the 48 Continental United States - OulsitJe the U.S. A, send 52.00 Others Including Alaska, Hawaii. P.R And Canada Must Pay fuU Shipping * MRfifl postage tar a catalog. Quantities Limited • No C.O.D. • Pnces Subject to change without notice. MAIL ORDERS TO: ALL ELECTRONICS CORP • P.O. BOX 567 • VAN NUYS, CA 91408 CIRCiE lOT ON FREE INFORMATION CARO DESCRAMBLERS All major brands carried *JERROLD, *TOCOM, *ZENrri! * GENERAL INSTRUMENTS ^SCIENTIFIC ATLANTA, *OAK *HAMLIN, *EAGLE, *PIONEER 7th Year m business. Tliank You Member of O mail a Chamber of Commerce 1 Year warrimLy on new equipment 30 Day money back guarantee Orders shipped from stock within 24 hours CALL TODAY FOR A FREE CATALOG 1-800-624-1150 H C.O.D. % A 875 so. 72nd St ^^QMa^^^ Omaha, NE 68114 1 C Q I UJ 6 IT 106 CIRCLE tea ON FREE INFORMAJiOM CARD CABLE BOXES BELOW WHOLESALE GUARANTEED STOCK - COD'S ■ DESCRAMBLERS - (QTY) (10) (20) (50) (100) TB 2-3 45 40 36 33 SA3-B 45 40 36 33 XN12 + 43 38 34 29 SB 2^3 43 38 34 30 €0 CH REMOTE CONV/DECODER DRX^DIC QO 75 70 65 SYL DIG 75 60 50 45 - CONVERTERS W/REMOTES ■ PANASONIC T2PC145 5 YR, WAR. -r PARENTAL + 86 CH TiMER + MEMORY + CH 2 OR 3 + NEW 70 65 61 57 REFURB 60 CH W/REMQTE S-4040 38 36 3d 31 HAMLJN-ZENITH-TOCOM-CALL IT IS NOT THE ISTES^TOF LAKE SVLVAhi £A4,ES tO OEFRAUO ANY CABLE r £ L i:S I O.N QPEFIATOS^ fEQ€.UAl AHH STATE LAWS PPCVIDE 'jU2STAMTI*L PENALTIES POR ThE^f LAKE SYLVAN SALES, INC. SORflv. NO MmNESOTA SALES 800-800-4582 DESCRAMBLERS PLUS! ADVERTISING INDEX R ADIO-ELECTRONiCS does not assume any responsibltity for errors that may appear in the index below. Free Information Number Page lOK AMC Sales-. 911 75 Acv rroducts , . . 102 J07 All KlLTiriinics 105 — Amji/JiiK Concepts , . , U)2 77 HtS^KPrcdsioii..,. , ,.,.,24 109 C&SSales ..B — CiE .......3, IK 198 CuMc Warehouse 76 5l> Caiji Lahur^lorics ............ 2(> I V) Chunesko Products Kfi — Command Proditctitms .... 1,1. 27 I K 1 Com m u nicatioas Spc^ual ists K7 55 Contact East , . . . Hf> 1K7 Datak Corporattwn . 26 127 Ueco industries Kf> IK2 Easj lbch 9^ IK3 Eicctronk Goldmine . . . , 94 — Electronic TecK. Toda^' ........ 80 — Electronics Book Club 2H 121 Fluke Manuracturinf> ....... CV2 17(1 Global .Specialties 7 — Grantham College , . . - 79 Kft Heatbkil 75 — HigbTcxI Publicalions, Inc. .... 24 — ICS Computer Training ....... 90 114 .lanugo , KXJ 180 Kelvin \m 199 Lake Silvan Sales, Iric* ...... UKj 200 M&t; Electronics . . . 9B H7 MCM Itlectrontes , yfi m MD Electronics 106 184 MKS Design Kfi 93 Mark V* Electronics _ 97 1 17 Mouscr 7f) — NRl Sebools H 71 NTE Electronics. CV3 195 Optoetectronlcs 17 S(f V^Tts Express 96 197 People's College . . . 25 78 Radio Sback 32 — H-E Video Offer. .64 177 SCO Eiectmnics .....81 196 TECI ....-V.,.,... 87 92,190 Tektronix 5.C\4 — Tbe Scbool of VCR Repair «3 194 Unicorn 103 178 Cable , . , . . . 81 192 J 93 Viejo Pithiicalions 13, 76 185 WI*1^ Publications , . 87 — VVniabec& Ward ,15 191 Worldwide Cable 98 186 Xandi Electronics 86 ADVERTfSING SALES OFFICE Gern^b^ick Publications, Inc, 500 & Bi County Blvd. Farmingdale. NY 11735 1 t5l63 293-3000 President: Larry Sleekier For Advertising OMLY 516 293-3000 Fax 1-516-293-3115 Larry Steckler publisher Christina Estrada assistant Id the President Arline Fish man tidvertising director Denise Haven advertising assistant Kelly M(xO"^(le credit manager Subscriber Custoiiier Service V800-288-0652 Order Entry for New Subscribers 1-800-999-7139 7:00 AM - 6:00 PM M F MST SALES OFFICES EAST/SOUTHEAST Stanley Levitan, Eastern Sales Manager RadiO'Electnortlcs 1 Overlook Ave. Gre<^t Neck. NY M021 1 -5 1 6-4 B7 - 9 3 57 . 1 - 5! 6- 2 93- 3000 Fax 1-516-487-8402 MIDWEST/Texas/Arkansas/Okla. R^lpb Bergen, Midwest Sdes Manager R^dio-Electmntcs One Northfieid Plazii. Suit© 300 NorthHeld, 1160093-1214 1.708-446-1444 Fan 1-708-559-0562 PACIFIC COAST/ Mt»un tarn States Maniin Green, P^icific Sales Manager Radio-Electronscs 5430 Van Nuys Blvd. Suite 316 Sherman Oaks, OA 91401 1-Bte'986-2001 Fan 1 (118-986 2009 RE Shopper Joe Sherei National Representative P.O^ Bok 169 Idyllwitd. OA 92549 1-714-659-9743 FaK 1-714-659 2469 CIRCLE 199 ON FREE INFORMATION CARD ■■- '» mil m£mrFsr.m/£srcffoss-ff£f£ff£mm OFOmGmLff£WC£SWN7F ff£PUC£MB ■ .283 ....97 . ■ M ■I te '5 Mjf?4j :2 m r249l WJE3055,. [f5 /WJt ^ Jaai ■ .m2 ■ ..38B2 ...3882 -3M2 3882 2117 2117 ■4164 2 ri ' Fin ♦ F -I ^70 M m74C9Q ft' ii,;;f :lip-^g3gi r YES, PLiASE SEND ME THE FOLLOWING NUMBER OF COPI£S OF ■a(f/rifCrtiS5 * SOFTWARE OK FLOPPY DISREniS svnum *5 OO ea 3^* (720K) »6.00«a, {US. funds QidfL) Name. Company. City. Altacti l!its cotipon ta yniir letterheid and mall io: ^HTI. 44 Farratid SL, BloomriBld, KJ O7003 RE292 — ^ — ' ■ ■ fW--' innff/fip WfCKCrvu' tottwiTC rui» MS DOS or) Mtv IBM PC or C> RAM , • un^l Itarti tfrlvf « and i S V< " or 1 3Mt " Hoppv drrve. t^es dI ii«rd space whan Toided. ii ua[lemaf1i qI International ■ I2#W K7 ir;:::^ ... WHAT YOUR TOOLS SAY ABOUT YOU. "Ultimate Professional" Heres the newest family member: the 60 MHz Tek 224, Its as mggcd, reliable and easy to use as fhe p^st of the 220 Sencs-and extended bana width makes it the logical choice for computer service professionals. "Rugged Survivalist" Teks 222PS Power Scour offers the field- proven per- formance of the 222, plus its rated 600 VAC, 850 VDC and 6 kV surge. Perfect for circuit measurtments requiring extra protection -and a feu' added guts. 'Ace Troubleshooter" Tlic Tck 222 is everything a service scojx- ought to lx\ Lightweight, Rugged. Fully programmable. Roa table to ±400 V. Two channels, 10 MHz, Auto Setup and Auto Trigger make it easy finding trt)uble-fast. They're jmt 414 pounds. U.L cenified. And start at $2450. 220 Series handheld oscilloscopes -all with Teks exclusive IsolatedChanner'* architecture - are the service tools the professionids use. Thcrcs one with you written all over h. To order, contact your Tck representative or distributor Or just call Tek direct: 1-800-426-2200 Tektronix /^si and n/teasurement Cofn^hf C 1991. S^^ssiaix, |nf .