SURROUND SOUND DE-MYSTIFIED JUNE 1990 TECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE BUILD THE LAWN RANGER Take it easy this summer with the worlds first practical robotic lawn mower! BUILD A UNIVERSAL GENERIC LINEAR POWER SUPPLY A single PC board design can be used to power dozens of projectsl ADD A DISPLAY TO YOUR NEXT PROJECT Step-by-step guide to using LCD display modules EXPERIMENT WITH I/O INTERFACING > How to build an experimenters card for the PC expansion bus SINGLE-CHIP XTAL OSCILLATOR Build a mini crystal-controlled frequency standard and pulse generator $2.50 U.S. $2.95 CAN .mS/0 VWffo "^^ rsana&xxxxxsx. 5-D?GIT 531 5f 750436HRR5I65J1Q33 " OS 48 FLUKE AND PHILIPS THE GLOBAL ALLIANCE IN TEST & MEASUREMENT FLUKI PHILIPS High Resolution Digital Meter: 4000 caum digital readout; 20,000 count mode (Fluke 87} (or 4'h -digit resolution Back lit display: Makes il easy to read the DMM in dark, cramped quartets. Automatically shuts _ oft alter 68 seconds to save trie battery. 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FLUKE 83 FLUKE 85 FLUKE 87 Vdis, ohms air-ps. diode ret. audtbieconltnuily. frequency and duty cycte capacilanc& rpici Hoid^relarive pm?eciiYt"flrsrtrwi'iF!M-Slanrf'~ 31 bait dcaecurac y 5HH1KV and;K>r, Ar^agtargraph and zoom Tbreeyearffarranly Three year warraal Recordei: records minirnums and maximums, plus true arilhrreiic average, audible Min Max Alert: selectable response times— 1 second and 100 ms [all models) plus 1 ms Peak Min Max (Fluke87) Frequency counter: Accurate down lo 0.5 Hz; also measures duly cycle Capacitance meter: Auloranrjing, with manual ranging at the touch of a button -$g>T <'/;?)![]■' mode Sjcltli I display Three ;rr ivarranly 'W]gsE'»ii Meet the meter that brings an entire test bench to your job. The versatile Fluke 80 Series do-just-about- everything "Multi" Meter. It oilers everything you'd expect from an advanced handheld DMM. plus a lot you'd find only in dedicated instruments. Plus Fluke-exclusive features you can't buy any- where else. 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CIRCLE 98 ON FREE INFORMATION CARD c z rr cc c Video News w o z o ir LU ( LLI 6 Q < • SO, 000,000 stereo TVs. At least 20,000,000 TV sets equipped for Multichannel Television Sound (MTS) stereo and second audio channel reception have now been sold, indicating that at least one American home in every five can receive television programs in stereo. Last year was MTS stereo's "biggest year, when more than 6,000,000 stereo-equipped sets were sold, representing 27.8% of all color TV set sales. That is an increase of almost a million sets over the 5,100,000 stereo sets sold in 1988, which represented 25.2% of that year's sales. In addition, about 1,800,000 VCR's sold in 1989 were able to receive MTS stereo broadcasts, up from 1,400,000 in 1988. • Welcome back, Majestic. Old-timers will soon see another familiar old brand back in television stores. That is Majestic, which is being revived as a label sold to independent retailers through distributors. The revival of Majestic follows the similar reincarnation of the Grosley brand (Radio-Electronics, August, 1989). Like the new Grosley brand, the new Majestic is no relation to its namesake. The new Maj estic brand is being made for a distributor organization by another old TV name — Wells-Gardner of Chicago, one of the oldest private-label TV manufacturers — from chassis and subassemblies understood to be made by Zenith. The new Crosley, as we reported earlier, is made by Worth American Philips. Other pioneer brands which have been revived by new parents include Capehart, Dumont, Emerson, and Symphonic. • Exit CD Video. Speaking of names, one that never caught on has been dropped. Philips and its affiliated record label, PolyGram, have abandoned their effort to promote "CD Video" as the new name for the optical videodisc. They adopted the name back in 1986, when the laser videodisc's fortunes were at a low ebb, in hopes that the magic of the audio CD would rub off onto the videodisc. One added attraction of CD Video was a new 5-inch version that contained up to 6 minutes of video and 20 minutes of digital audio. The 5-incher never caught on, but combination CD and videodisc players brought a revival of the DAVID LACHENBRUCH, CONTRIBUTIHG EDITOR videodisc, which is becoming increasingly popular. Now Philips and other manufacturers have agreed on a single name: "Laserdisc." • Sky Cable. Activity on the direct satellite broadcasting front indicates that a television revolution will soon be under way. Two groups have announced plans for new satellite ventures. U.S. Satellite Broadcasting signed an agreement with GE Astrospace to acquire a three-channel satellite to broadcast directly to home antennas, with nationwide Insurance as a partner. A second announcement stirred up much more publicity. A consortium consisting of NBC, Cablevision Systems, and Rupert Murdoch's Hews Corporation said they will launch a high-powered direct satellite service hi 1993 with up to 108 channels. Using three satellites in the same orbital slot as US, Satellite Broadcasting's bird, "Sky Cable" will provide as many as 128 channels. The Sky Cable consortium said the 200- watt power of its transponders will make it possible for homes to use small flat antennas measuring about 12 inches square. Transmission from the earth to the satellite will be digital, but the satellite will send out analog video signals. It was estimated that receiving antennas plus receivers for the satellite will cost $200 to $300. It's called "Sky Cable" because the sponsors hope to make It available through local cable operators for a monthly fee, but if consumers wish to purchase the equipment and pay the sateUite broadcaster directly they may do so as well. Both NBC and the News Corp. (Fox Broadcasting) insisted that none of their network programs would be broadcast on the satellite, and Cablevision said the system would be a supplement to cable and not a replacement. But it was difficult to see what function terrestrial broadcasting or cable would serve when 128 channels could be picked up from sateUites with a small investment on the part of the public, and there was some feeling that investments in the billion-dollar project by its network and cable sponsors was a defensive maneuver — just on the chance that direct satellite broadcasting might make broadcasting and cable obsolete. E.-E No matter where you go, Tek's new 222 is a perfect fit. Introducing Tek's new 222 Digital Oscilloscope. Weighing in at under 4.5 pounds, the new Tek 222 is an ultra-portable, 10-MHz digital storage scope that's perfect for service applications. So tough, rugged, and totally self-contained, it can go just about anywhere. And it's incredibly easy to use — even in extreme conditions. 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Ttektronix COMMITTED TO EXCELLENCE m CIRCLE 92 ON FREE INFORMATION CARD IHH-9II o Ask R'E WRITE TO: ASK R-E Radio-Electronics 500-B Bi-County Blvd. Farmingdale, NY 11735 o z o CL UJ _l til G Q < LINES OF RESOLUTION Please tell me something about the horizontal resolution of the NTSC sys- tem. According to the standard, there are 525 horizontal lines per frame, but my VCR only puts out 230 lines. Is that lines per field or lines per frame? Sony ED Beta machines claim to have more than 500 lines and some studio cam- eras are rated at above 600 lines — more than the NTSC standard. How can a TV display more than 525 lines? And could you explain what dif- ference there is between a "composite video output" and a "video out- put?''— M. Hart, Burbank, CA I can understand your confusion but you shouldn't feel too bad be- cause the whole issue of video reso- lution is confusing. Even some friends of mine who use the video business to pay the rent don't have a clear understanding of exactly what the numbers mean. Let's start with a bit of history. The whole idea of using numbers of lines to measure resolution had its beginnings in the lens business. As lens making progressed from broken bottle bottoms to fluoride coating and lasers, a standard was developed to measure the amount of detail a lens could transmit. As you've probably guessed, the unit that was chosen was the number of lines per millimeter. A "line of resolution" is defined as an equal amount of white and black area as shown in Fig. 1. A typical resolution chart would have a series of lines that get thinner and more closely packed as you move across the chart. In practice, the lens would be pointed at the chart and the projected image would be ex- amined to see at what point it be- came impossible to see individual lines. That point would be desig- nated as the resolving power of the lens. 4 lines per mm 8 lines per 16 Unes per mn 3c? lines per nn FIG. 1 It should be obvious to you that there's a problem with this method since lenses don't have equal resolv- ing power at every point on the glass. That is due, in part, to the- oretical consequences of the optical paths of the light, and also with practical considerations of grinding glass; a lens is usually much sharper at the center than it is at the edges. That's why the published resolution of a lens is specified for a particular point on the lens — usually the cen- ter where the image is the sharpest. The lines-of-resolution method of measuring the sharpness of a lens was carried over to most of the in- dustries that were involved in the business of reproducing images. That includes printing, film, and vid- eo. Each industry is concerned with the amount of detail that they can reproduce, but they also have characteristics that differ from the lens business. So, while they all re- fer to lines when they talk about resolution, they aren't all talking about the same thing. In short, the video industry has made too much use of the word "line." You're correct in saying that the NTSC standard calls for 525 lines per frame, but you didn't go far enough . Standard NTSC video doesn't just call for 525 lines per frame, it's that way by definition. Each field con- tains 262.5 lines, and two fields make one frame of video. A video signal that puts out anything other than that just isn't conforming to the NTSC standard. The signal timing may be such that you can display it on an NTSC-standard monitor, but that means that it's really only "NTSC compatible." Now, with that out of the way, ex- actly what does it mean to say that some video device puts out 200, 300, 500, or 600 lines? What it means is that there are two different kinds of lines: the first is a line of video and the second is a line of resolu- tion. And what, you may well ask, do they have to do with each other? Absolutely nothing! The way to understand how the lines of resolution in video relate to the lines of resolution used in optics is to realize that video resolution deals with the number of dots on each individual horizontal line of video. Your VCR can put out 230 lines of resolution, but what that really means is that it can display up to 230 individual dots on each line. Imagine that, using a video camera and a resolution chart similar to the one in Fig. 1, you made a tape show- ing a few seconds of 200 vertical lines, then 201, 202, 203, etc., on up to and past 230. When shown on a TV, the image would look like ver- tical lines, but it would really be a series of dots. As soon as the number of lines passed 230, the im- age from your VCR would become a gray blur rather than a series of indi- vidual lines. To get electronic about things, the resolution of a video device is a direct function of the bandwidth— the more quickly it can turn dots on and off, the higher the bandwidth and the better the resolution on each line. As a rule of thumb, you can say that there about are eighty lines of resolution per megahertz of bandwidth. Sony's ED Beta VCR claims to have more than 500 lines of resolution (we know that really means 500 individually distinguisha- ble dots per horizontal line) at about 9.3 MHz... and that brings out an- other point worth mentioning. Our 80-line-per-megahertz rule doesn't seem to work with the Sony because we haven't talked about all the other parts of the signal. A portion of the bandwidth has to be used for the various subcarriers, IF, color, and so on. And don't forget that not all of the horizontal line of video is used for picture — more than 16% of each line is reserved for the horizontal interval where you'll find such goodies as burst and hori- zontal sync. Another factor to con- sider is the capability of the recording media. Metal tape can handle a higher bandwidth (which is another way of saying it has a high- er frequency response), but even the best tape in the world just can't handle the maximum resolution de- liverable by the ED Beta machine. As far as what the difference is between the "video" and "com- posite video" outputs, I think we're dealing with a lack of standard. Composite video is a single signal containing both picture information and sync, while a plain video signal may just contain only the picture information. 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The correct address is R & R As- sociates, 3106 Glendon Avenue, Los Angeles, CA 90034— not "31066" as was printed. {Perhaps the extra digit wouldn't make a difference in most places, but we've been informed that on Glendon Avenue — which was once featured in a television- news fi Her as one of the most con- fusing streets in Los Angeles — residents have enough problems with even properly addressed mail.) Sorry for the added con- fusion. • In our Universal Descrambler story (Radio-Electronics, May 1990), the parts list contained a couple of errors. First, the correct part number for IC9 is CD22402E. Also, there were two C39's; the 47 pF NPO is actually C34. In Fig. 3, what's shown as pin 16 of IC4-C is actually pin 14. The unlabeled capacitor above IC4-d is C45. In Fig. 4, polarity switch S3 should go to +5 volts, not ground. calls and the FCC reported that they had several hundred calls complain- ing of interference on channel 4. The station then ran an endless tape loop explaining that the SAP channel was selected and the view- er should consult his owner's man- ual for instructions on how to return to program audio. Again the phone calls poured in. Some viewers even insisted that the station send some- one to "fix" their TV sets. Finally, after three or four weeks, the calls began to taper off. At that point, the station began to broad- cast NOAA audio again. The phone calls returned, in increasing num- bers each day. After a week, the SAP channel was turned off for good. I suspect that the SAP channel will never be used for anything other than regular-programming audio. ROBERT FUTSCHER Alexandria, VA THE CORRECT WAVEFORM I am writing to congratulate you on an excellent article, "Glitches in the Power Line" (Radio-Electronics, April 1990). In all the magazines and books I have ever read, only Radio Engineering by Terman showed cor- rect waveforms for rectifiers and fil- ters. Now Radio-Electronics has become number two, with Fig. 2 in the article. Usually the waveform of part (a) is shown while the filter and load are intact, but in truth that waveform is correct only with no filter and no load or with purely re- sistive load only, as the article cor- rectly pointed out. The shapes and phasing of parts (b) and (c) are about as nearly correct as the drawing scale would permit. I have pointed out errors shown in respected hand- books to editors who refuse to cor- rect their figures. The rest of the article is very inter- esting, and it was obviously written by someone who knows the facts. KENNETH E. STONE Chenyvale, KS COMPARING CD PLAYERS I must take issue with Dwayne Rosenburgh's letter in the March is- sue regarding Larry Klein's De- cember "Audio Update" column, which dealt with sonic differences between CD players. Rosenburgh believes that the ABX tests to which Klein refers prove only that there are no significant differences between expensive CD players and that a "$1500 unit will always sound better than a $300 model." Rosenburgh is overlooking the fact (mentioned in the column) that two sets of ABX tests were conducted. The second dealt with costly players, but the first set dealt with machines ranging in price from a $450 Emerson (fre- quently discounted to $200) to a $1400 Meridian. On both occasions the ability of listeners to differenti- ate between any two CD players to a statistically significant degree, 75% of the time, with music as opposed to test signals, was rare. As a case in point, listeners could distinguish between the Emerson and a $13000 reference Sony 26 out of 40 times with orchestral music and 21 out of 40 times with jazz. The same lis- teners could distinguish the Sony from the Meridan 21 out of 40 times with orchestral music and 20 out of 40 times with jazz. The averages were thus 51% and 59% for the Me- ridian and the Emerson, respec- tively. A 50% average could be achieved by pure chance. The only conclusion we can reach from those tests is that there are subtle sonic differences between CD players, but the differences between cheap and expensive players are no great- DELUXE TEST LEAD KIT Users call TPI test leads The Absolute Best. The TLS2000 features the highest quality cable in the industry — with spring- loaded safety-sleeved plugs. U.L. listed (file E79581). Kit: $29. Leads & probes only: $19. Satisfaction guaranteed. TEST PROBES INC. Call toll-free for catalog: 1-800-368-5719. CIRCLE 208 ON FREE INFORMATION CARD VHH ■ ,iHl.f * >' y «■' v if TT'I T 1 i^^h 1 BNC ATTENUATOR KIT Contains 4 attenuators — 3dB, 6dB, lOdB, 20dB; 1 feedthrough and 1 termination. Thick- film circuitry for low reactances. Rugged de- sign resists shock and lasts longer. Rectangular shape stays put on the bench. Impedance: 5011 Frequency: I GHz. 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For very high quality refer- ence tapes of all types, request a catalog from Magnetic Reference Laboratories, 229 Polaris Avenue, Suite 4, Mountain View, CA 94043 (415-965-8187).— Larry Klein, Audio Editor THERMOELECTRIC ENTHUSIAST I am one of those "arcane" engi- Be an FCC LICENSED ELECTRONIC TECHNICIAN! No cosily School. No commuting to class. The Original Home-Study course pre- pares you for the "FCC Commercial Radio- telephone License' ". This valuable license is your "ticket" to thousands of exciting jobs in Communications, Radio-TV. Micro- wave, Computers. Radar. Avionics and more! 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. Send for FREE_fa_cts_now._ _MAIL COUPON TODAY! r comrtimiD niblwcf ions' " "! FCC LICENSE TRAINING, Dept. 90 ■ P.O. Box 2824, San Francisco, CA 94126 Please rush FREE details immediately! | NAME I ADDRESS CITY STATE ZIP neers who thinks that ther- moelectric modules are one of the greatest things to hit the planet in a long time (Hardware Hacker, Radio- Electronics, January 1990), along with the U.S. space program, the French railways, and the U.S. submarine fleet. For one thing, the hot side of the thermoelectric module can al- ways be kept at an ambient temper- ature by water cooling its heat sink. (My unit runs at 5°F above ambient with an extremely small "hot" sink and air cooling.) My unit was put into service in 1976 and has an excel- lent refrigeration record. Also, elim- inating compressors, freon, plumb- ing ammonia, C0 2 , and ozone destruction more than compen- sates for any supposed limitations. And finally, yes, my unit does make ice, at about the same rate and time as my freon refrigerator. J. LINDNER San Jose, CA PCjr DOCUMENTATION I was pleased to read in Shawn Bobbit's letter {Letters, Radio-Elec- tronics, February 1990) that he re- cently purchased an IBM PCjr, and was sorry to learn of his difficulty in obtaining technical information re- garding the PCjr. In fact, technical literature is available for all of IBM's Personal Computers, including the PCjr. The "Hardware Technical Ref- erence Manual for the PCjr" is listed in the current directory of technical literature for IBM's PC's. A call to the toll-free number (800-IBM-PCTB) confirmed that the manual is cur- rently available. I hope this information comes in handy for Mr. Bobbitt and other Ra- dio-Electronics readers. JOHN R. SOMMA IBM Corporation White Plains, NY LEFT-RIGHT IMBALANCE In regard to Larry Klein's discus- sion on L-R speaker imbalance, I have found that the problem is often due to the values of the capacitors in the crossover networks; they shift over time. Also, all connections from the amplifier output to the speaker itself must be good. A poor connection anywhere in the line will cause a considerable loss of power to that speaker. JOHN S. COX Vancouver, BC R-E 16 ONCE YOU'VE GOT IT DESIGNED, YOU'VE GOT IT MADE. Now you can take those hot, new logic or block design diagrams, and quickly, easily bring them up to reality... in minutes. ..without solder! Build circuits as fast as you can think. Test. Modify. Expand. Without burned-out parts or burnt fingers. Save time, money. ..and prove that you know that you're talking about... before you use your CAD. Specify PROTO 80ARD Brand, Today's rec- ognized Standard for Quality in breadboard- ing. Here are five expandable breadboards, offering countless arrays of solderless sock- ets and bus strips that emulate pc board lay- outs. Pop in components. Pop them out again. Microprocessors. Memory. Large DIPs. Tiny discretes. Makes no difference. The pat- ented aluminum backplane lets you work at Call toll-free for details 1-800-572-1028 frequencies from DC to half-a-GigaHertz or 500MHz. Need power? A powered PROTO BOARD Brand offers up to triple voltage power supplies, +5V, + 12V, - 12V, with reg- ulated/current limited DC power. Over 2.250 tie points with 24 IC capacity and 14 pin DIPs. Super for TTL, CMOS, Op-Amps and microprocessor circuits. And lots more. Best of all, your hassle-free American-made PROTO BOARD Brand comes with an unlim- ited lifetime guarantee on all the breadboard sockets. Prices are so modest, you'll wonder why you waited this long to specify PROTO BOARD Bran d. Or der today. GLOBAL SPECIALTIES Global Specialties. An Intefplex Electronics Company. 70 Fulton Terrace. New Haven, CT 06512. Telephone: (203) 624-3103. $ Interplex Electronics 1989. All Global Specialties breadboarding products made in USA. AO0VC CIRCLE 186 ON FREE INFORMATION CARD m CO o 17 Equipment Reports w o z o i UJ o Q NC/ R44S0 PC-Based Logic Analyzer Turn your PC into a 48- channel, 25-MHz Logic Analyzer CIRCLE 10 ON FREE INFORMATION CARD ONE OF THE OFTEN-IGNORED RESULTS of the "computer revolution" is that PC-based instrumentation is rapidly taking over many phases of product development. Today, an engineer working at his PC can design, de- bug, and test a new product. A good example of how it's happening is the Look what you can si ill Ihi y f or only I 00 RESIST. U4V-' H'JdOaOh.ii 35niJi RESIST U4W IS5 3.16K 2F7,_X£1 KKEiI=!T 1MW ITZ 3.93K 25CWS3 hes;;"i :/j-.v t" " ik spo/si RESIST :/-AW BS8 1QK. 2DO'Sl RESIST 1/-". T .V 59t 47 K: 2UOr$l RESIST. W4W S-?$ 1 JvIEXS EOCWyi TR1MPOT SK. Hor 10#«J . : (POT lOK Vert. i ■'■■•<: TRJMPOT 2SK iior ;0/$i rPOT SOK Vrrt 1D/X1 ItTAl OSO. 1 £!*••-■ "-•£: xtal ■:"; : ' I nz. ; »sa XT.AL OSC. 6.000 I t "-•:.: 5 -'J: rTL UiMTmr-Jtod JO/T.l 2»-39Q4 Trans T7nr.isi'l'.e a POfS: 1K-4O05 Diotlo UhmarkBiJ 5 "Si 1 1: - i: mui ripnc tism ~ .■" -. i- 1- ■ ■■•-. Tl arMTlfft.RINT TO-orUnrai'.-ii"';^'! .■■■ : a/ >CiOV T(i-?:'!. 5**i SC£ 4A-4POV GE OlOeiEKl •»/*! -. i " K TIES 4" irvlon SOW I MPS L'2?? Transistor ISIfl TR1MCAPS 7-rv*pf 6'St j i- :r ICAPE lO-IOOpI 5/SU TRIMCAPS S SOpf 5/S1 Trar:i-:!stMPS-3MO Hf- » ZQfit) EP»v 92 R!F «=,IvI]= to 4.5.GHZ S*£l HESIST.ASST. 1/1W <=,?* Ol" btscter SCi Vals.ffiOpc o» iCtorj/S'l REStST.ASST. i.'JV- 2S Val5.«Clpci ■?.■* SOD/S-fl CHIP Resist. 1 SOB BOO Ohm 20* -'- DIODES same bli lWamB BCWS1 SH1P:ADD S3 COD:$? EXTRA FREE CATALOG NO IV1IN ORDER SHORT CIRCUITS p.o. box 285 BARNEGAT, NJ 08005 ph : BQ9-B9B-3080 f&x~. 609-69B-8B09 PA480 PC-based logic analyzer from NCI (6438 University Drive, Hunt- sville, Alabama 35806). Trie PA4S0 consists of a main log- ic-analyzer card, an interface cable, and an acquisition pod. The main tawrttu liipLq dllKfMIld nicrcppXKKr jrtstrMCtitfrS AjwiuL BtvL«4 trjct « nuntrici] dati liv* livlw timing di*gr*i *:- Slwt of led frt» md tran ts mj Fran ii«± fomit &st » cl«k4, dwtL ww, Fu>td Fowls, h«I *ddto* Tri^r Sri v tri^rr vilwi md trigger &l*i Bnwn rfl v iw l»|j card plugs into a free slot of a PC. A DIP switch allows the user to change the address at which the card resides to avoid conflicts with other boards that may be installed in the computer. After the board is in- stalled, a 60-conductor flat ribbon interface-cable is attached to it at the computer's rear panel. The other end is attached to the pod. Using the analyzer Once the simple mechanical in- stallation is complete, the computer is powered up, the pod is connected to the circuit of interest, and the operating software is run. While the software is dependent on the par- ticular pod being used, a represen- tative example of the main or command menu is shown in Fig. 1. The best way to explain the opera- tion of the analyzer is to look at each of the main menu commands, al- though not necessarily in the order they're presented. The first one we'll look at is the go command, which initiates the acquisition of data and the generation of a new trace, the pictorial display of data. FIG. 1 c:0BSB5 1-0858? r:B8479 c - r>: *BB01.B4us c - i: -BB8B.98us r - t: -BBB1 Mag/Xpatui Z Edit Clock Align [+/-] scroll Go Split Trig Uards - 1895 IZus Name Chiil It m Bl Al B2 A2 83 A3 04 A4 85 AS Be At 87 A7 68 m 69 A9 IB AiB 11 All IE AI2 13 A13 14 Ail 15 AI5 IS IB 17 III IB DZ 19 D3 ZB liJiriimjiiJLWiJirw^^ Lmrajniurruiiiriri^^ l^jTTL_iirTioTnm-LJiJTnrTJLJT^^ nn_jnimn inimn irumn runun !rumn_ JinTLJTT_JTTXJT^JTIXJT _ LJirLJTT_JTrLJT jlj i_n n_n n_n n_j imnrrmr i nuL i i ii n_Ln_ nnj— Jim. rnr fUUL irrr" _IlUL J_ JiUIUOJUUUl l_UUUL JUULO- JJLU1 LX1UJLJI JL_ _■_ _L JL J_ -L mill mi i n imnin nimmin nirmniin nirmmn nimm MiiJiJirjmiiJiLiLmaiium^^ ULLlUlJJL'-lJUaMJLJJJJJJURUUJlJllliaiJUJJ^^ U 1U1IILJIJJJIMIJJJUII1ILJU11III»L^^ FIG. 2 18 Radio Shack Parts Place YOUR ONE-STOP STORE FOR BIG ELECTRONIC VALUES Build with the Best— Over 1000 Components in Stock! Amateur Radio License Guides Parts "Hotline" Service! Thousands of Items Available Your Radio Shack store manager can special-order a huge variety of parts and accessories direct from our electronics warehouse — Realistic* Long- Life tubes, linear and digital ICs, microprocessors, support chips, phono cartridges and styli, crystals, special- purpose batteries, diodes, selected modules for TVs and audio equipment, autosound wiring harnesses, accessories, even SAMS Photofacts*. No handling charge, no shipping charge— just speedy delivery to the Radio Shack near you! Brushless Fan fl 16 95 ir Detector Operates On 12VDC Tiny, tough and efficient! Rated 150 mA. Wiex 1*6X1*8" #273-244 349 Module operates on 5VDC, board mountable. %x Vaxisfoa". With data. #276-137 n ml Simplifies IR Design Diode Rectifiers Speaker Stuff 3-Amp "Barrel" 2 00 -Amp Type Diodes Surge Type Pealt Inverse Voltage Car No. Pk B . 012 1NW00 1N5402 1N5404 50 200 400 276-1141 275-1143 276-1144 1.19 1.29 (1) MEGACA8LE". Hi-wattage. 12- gauge. #278-1268 ... Per Foot 99 « (2) Gold Terminals for MEGA- CABLE. #64-401 ... Set of 8/4.99 (3) Terminal Knobs. Screw-down large cable. #274-619 ... Set 5.9S cold-Plated Plugs and jacks (1) Phono Plug, #274-850 . . 2.49 (2) Chassis-Mount Phono Jack. #274-853 2-pk./2,49 (3) Straight Inline Phono Jack. #274-854 2.99 (4) 2-Conductor Vt" Phone Plug. . Monaural, #274-855 3.49 /, (5) Three -Conductor (Stereo) V«" Phone Plug. #274-856 3.99 (6) W Plug. #274-857 2.79 (7) 3-Conductor. Va" Phone Plug. Stereo. #274-858 3,49 (8) 3-Conductor 1 /o" Inline Phone Jack. #274-859 3.99 495 ,„ 1995 Home Study Courses For FCC License Tests Novice Voice Class License Prep Course. With cassettes. #62-2402 19.95 Technician Class Manual. #62-2403 4.9S General Class FCC License Course. #62-2404 19.95 ic Tool set 695 err' ^* set mam m Install and remove 6-pin to 40-pin DIPs without damage. Works with LSI, MSI. and DIP devices. Both tools are groundable. #276-1581 Motor and Chime Dress it up (1) 1.5-3V DC Motor. For robotics, projects.lVsx's/is" dia. #273-223 (2) Doorbell Chime. ICYmini-speaker combo. 6-18VDC. 5" leads. #273-071 Halogen Lamps (2) (1) Classy Two-Piece Enclosure. Accepts PC board and 9V battery. 5 s /b X 2V4 X 1 Vis': #270-257 . . 4.99 (2) Project Labels. Four 7%x3" sheets of rub -on letters and symbols. #270-201 Set 2.99 (1) e li (»iii 395 Each (1) HPR50. For 4-cell flashlights and 6-volt lanterns. #272-1189 (2) HPR52. For 2-ceJI flashlights and 3 -volt lanterns. #272-1190 wire Connectors & Accessories (D •;■ (2) ™ wtmm (4) (5) (6} (7) Fig PD5 Type Amps Cat. No. Each ' 2 6 12 Male Male Male 20 15 12 274-151 274-152 274-153 .99 1.59 1.99 2 2 6 12 FemaJe Female Female 20 15 12 274-154 274-155 274-156 99 1.69 1 35 3) 2-P.ow Strip. #274-670 ... 1.99 4) Jumper. 8-pos. #274-650, 1.59 ;5) 45° T-Lugs. #274-645 . . 4/79C (6) Dual Solder-Lug Adapters. #274-644 Pkg. of 4/796 (7) Heavy-Duty Bonded Wire. 25 ft., 2x18-gauge. #278-1250 3.99 Engineering calculator 39 95 Uses Standard Electronic Symbols EC-4035 makes design math a snap! Has 110 func- tions, memory. With case and batteries. #65-983 II ut m lj h ej aqaaaB uLit, - oae 30-Range Multimeter 79 95 Tests Capacitors and Transistors A great value! Measures to 1000V DC and 750 VAC With 0.5" digital display. Battery ex- tra. #22-194 Over 1000 Items In stock! Binding Posts, Books, Breadboards, Buzzers, Capacitors, Chokes, Clips, Coax, Connectors, Fuses, Hardware, ICs, Jacks, Knobs, Lamps, Multitesters, PC Boards, Plugs, Rectifiers, Resistors, Switches, Tools, Transformers, Transistors, Wire, Zeners, More! L Prices apply at participating Radio Shack stcras and dealers panel-Mount Counter 1495 Electromechanical —Counts to 99,999 One count per 12VDC pulse, pushbutton reset. Mounts in I'Viexl" hole. Depth: 1 i: Vis" With leads and data. #277-222 A DIVISION OF TANDY CORPORATION C z m to O 19 CIRCLE 78 ON FREE INFORMATION CARD Put Professional Knowledge and a COLLEGE DEGREE in your Technical Career through HOME STUDY CO o z o E P o LLI Add prestige and earning power to your technical career by earning your Associate or Bachelor degree through directed home study. Grantham College of Engineering awards accredited degrees in electronics and computers. An important part of being pre- pared to move up is holding the right college degree, and the abso- lutely necessary part is knowing your field. Grantham can help you both ways — to learn more and to earn your degree in the process. Grantham offers two degree pro- grams — one with major emphasis in electronics, the other with major emphasis in computers. Associate and bachelor degrees are awarded in each program, and both pro- grams are available completely by correspondence. No commuting to class. Study at your own pace, while continuing on your present job. Learn from easy-to-understand lessons, with help from your Grantham instruc- tors when you need it. Write for our free catalog (see address below), or phone us at toll-free 1-800-955-2527 (for catalog requests only) and ask for our "degree catalog." • Accredited by the Accrediting Commission of the National Home Stud) 1 Council GRANTHAM College of Engineering 10570 Humbolt Street Los Alamitos, CA 90720 ADGVE © MftUtt* ^ tefi ' 9 H£SS*"' ;h P !2JU * •tT m + untron DC Line Sentry Voltage Monitor Keep tabs on low-voltage DC power supplies. CIRCLE 11 ON FREE INFORMATION CARD ONE OF THE MOST DIFFICULT PROBLEMS for the technician to diagnose is the intermittent one. Often, the most effective way to catch the problem is sheer luck. In the absence of luck, expensive test equipment — such as storage scopes or chart recorders — must be called into action. While intermittent problems can appear anywhere in a circuit, their causes can often be tracked back to the power-supply section. That's the idea behind the DC Line Sentry from Huntron Instruments, Inc. (15720 Mill Creek Blvd., Mill Creek, WA 98012). The DC Line Sentry lets you keep tabs on a power supply without calling out the "heavy artill- ery." It's an easy-to-use voltage monitor that can detect and "re- member" whether a power supply stays within specified limits during the time it is monitored. It" the power supply passes the test, yet an intermittent problem occurs, then you know to look elsewhere for the source of the trouble. The DC Line Sentry is housed in a gray plastic case that measures roughly 416x3^x1% inches and weighs about Vi pound. It's powered by a 9-volt alkaline battery. The front panel contains two input banana jacks, four slide switches, and 6 LED indicators. To use the unjt, the supplied test leads are inserted in the input jacks, and are hooked to the supply under test. A pair of switches is used to select one of the four test voltages: + 5, +12, +15, and +24 volts. A third switch is used to select either a 5% or 10% tolerance range, and the fourth switch powers up the tester. When the tester is turned on, the green in range LED should flash to indicate that everything's OK, and the DC Line Sentry is monitoring the voltage. If however, you acci- dentally hooked up the test leads backward, the red negative LED would flash. You would then have to switch the leads and reset the tester with the power switch by turning it off and on. The DC Line Sentry can detect any out-of-range condition with a duration greater than 50 millise- conds. If the supply voltage goes above the set limit, the above LED will flash. If the voltage then returns to its correct value, both the in range and above indicators will flash. As you might expect, an un- der-voltage condition will start a below LED flashing, and a power failure will flash the power failed indicator. A sixth LED is used to indicate battery condition. When the battery gets weak, the low battery LED flashes. The indicator remains on steadily when the battery must be replaced. The estimated lifetime for a 9-volt alkaline battery is 2000 hours. That should be long enough to catch all but the most stubborn power-supply intermittent. Huntron's DC Line Sentry is cer- tainly not a revolutionary new piece of test gear. There ts other equip- ment that can duplicate its func- tionality. Even some high-end digital multimeters can capture slow power-supply glitches. Yet the DC Line Sentry has its ad- vantages : It's extremely easy to use, and it lets the more expensive alter- natives be used for more demand- ing tasks. With a suggested retail price of $125, it should find many applications in which it can prove its cost-effectiveness. R-E 20 LOGIC ANALYZER continued from page 18 Electronics DiMtnlD^E Once the data is acquired, there are several different ways to display it. The diagram command displays the captured data in the form of a timing diagram, as shown in Fig. 2. It should look familiar to anyone who has ever examined a data book or seen a logic analyzer in action. A pair of cursors (which are barely visible at the left side of the diagram in Fig. 2) help to make measure- ments easier. Notice the numbers down the right side of the display. They indicate the value of the trace at the cursor position. As the cursor is scrolled through the display, those numbers change, as do the numbers across the top of the screen the indicate the position of the cursors and trigger, and timing differences between them. The assembly command displays any data that has been captured as disassembled microprocessor in- structions. The command is specific to the pod being used. For example, if you used a 8088 pod, and captured data from the data bus of an operat- ing 8088 microprocessor, you could display those data as the micro- processor's mnemonics. The numerical command dis- plays the data in a user-chosen nu- merical format, which is entered from the format menu. The user can divide the data from various channels into eight user-defined fields. For example, 16 channels could be used to examine the ad- dress bus of a microprocessor, while another 16 channels gathered data from the data bus. Each grouping of input channels can have an 8- character name, and the data can be displayed in hex, binary, octal, deci- mal, or ASCII formats. Switching to the record menu al- lows trace data, numerical data, set- up conditions, and the like to be stored or recalled to or from disk. It is one of the features that become simple on PC-based systems. The trigger menu allows up to 16 trigger words to be entered, while the trigger sequence menu provides a powerful trigger selection and edi- ting menu. The trigger sequence can have up to 16 levels, and can use a total of 16 continued on page 87 THE MODEL WTT-20 IS ONLY THE SIZE OF A DIME, yet transmits both sides of a tele- phone conversation to any FM radio with crystal clarity. Telephone line powered - never needs a battery! Up to V* mile range. Adjusta- ble from 70-130 MHZ. Complete kit $29.95 + $1.50 S-t-H. Free Shipping on 2 or more! COD add $4. Call or send VISA, MC. MO. DECO INDUSTRIES, Box G07, Bedford Hills, NY 10507. (914) 232-3878. CIRCLE 127 ON FREE INFORMATION CARD CALL NOW AND RESERVE YOUR SPACE • 6 x rate $940.00 per each insertion. • Fast reader service cycle. • Short lead time for the placement of ads. • We typeset and layout the ad at no additional charge. Call 516-293-3000 to reserve space. Ask for Arline Fishman. Limited number of pages available. Mail materials to: mini-ADS. RADIO-ELECTRONICS, 500- S Bi-County Blvd., Farmingdale, NY 11735. contact east SAME DAY SHIPPING P55 FREE 1990 GENERAL CATALOG OF TOOLS & TEST INSTRUMENTS. Contact East's new 148 page catalog offers products for testing, repairing and assembling elec- tronic equipment, ft comes packed with over 10,000 quality products from brand-name manufacturers. Included are DMM's, probes, static supplies, hand tools, toot kits, test equipment and more. Contains full color pho- tos, descriptions and discounted pricing. CONTACT EAST, 335 Willow St., North An- dover, MA 01845 (508) 682-2000. CIRCLE 55 ON FREE INFORMATION CARD CABLE TV CONVERTERS AND DE- SCRAMBLERS SB-3 $79.00 TRI-BI $95.00 MLD-$79.00 M35B $69.00 DRZ-DiC $149.00. Special combos available. We ship COD. Quantity discounts. Call for pricing on other products. Dealers wanted. FREE CATA- LOG. We stand behind our products where others fail. One year warranty. ACE PROD- UCTS. P.O. Box 582, Saco, ME 04072 1 (800) 234-0726. CIRCLE 75 ON FREE INFORMATION CARD IT-10 INTERFACE TUTOR. Explore comput- er interfacing with high-quality IBM-PC-com- patible hardware. The circuit board with speaker, keypad, A/D, D/A, DIO, and step- ping motor permits hands-on study of inter- facing tasks and custom experiments. Includes manuals and exercises. Product de- veloped by the author of Hardware and Soft- ware Interfacing for IBM PCs and used in colleges worldwide. ROYER ASSOCIATES, 206 Santa Margarita Ave., Menlo Park, CA 94025,(415)326-8079. CIRCLE 187 ON FREE INFORMATION CARD SIMPLY SNAP THE WAT-50 MINIATURE FM TRANSMITTER on top of a 9v battery and hear every sound in an entire house up to 1 mile away! Adjustable from 70-130 MHZ. Use with any FM radio. Complete kit $29.95 + S1.50 S + H. Free shipping on 2 or more! COD add $4. Call or send VISA. MC. MO. DECO INDUSTRIES, Box 607, Bedford Hills, NY 10507,(914)232-3878. CIRCLE 127 ON FREE INFORMATION CARD to o 21 New Products 03 O z O cc P o LJ -I LU 6 q < CL MINIATURE COMPUTER SYSTEM, Ampro's Mini- Module expansion board couples their Little Board/386, /286, or /PC sin- gle-board computers to Reflection Technology's Pri- vate Eye display (Radio-Elec- tronics, February 1990) to form a complete system that takes up less space than a standard 5V4-tnch disk drive. The Private Eye display uses proprietary technology to create an image of a 12-inch monitor in a miniature pack- age that measures just 1.2x1.3x3.2 inches and weighs about 2 ounces. When held to the eye or mounted on a headset for hands-free viewing, the im- age appears to float in space in front of the viewer's eye with quality and resolution matching that of a PC display. The new MiniModule/Pri- vate Eye provides the elec- tronics to drive the Private Eye as an IBM CGA-compati- ble graphics display when used with any PC- or AT- based application software and one of Ampro's Little Board single-board systems. It features rugged, industrial- grade design, a wide operat- ing temperature range (0-70°C), and CMOS con- CIRCLE 26 ON FREE INFORMATION CARD struction for low power con- sumption (less than 0.5 watts) from the +5-volt sup- ply. Each MiniModule is a 3.5 x 3.8-inch circuit board that attaches directly to a sin- gle-board system and inter- faces via PC-bus-compatible signals. The small size and low power consumption open the door for a wide range of portable applications for the MiniModule/Private Eye with single-board systems, in- cluding telecommunica- tions, portable terminals, mobile data displays, porta- ble data-entry and -retrieval systems, medical elec- tronics, industrial control- lers, and maintenance and repair work. The MiniModule/Private eye is priced at $250.00 in quantities of 100. — Ampro Computers Inc., 1130 Moun- tain View/Alvtso Road, Sun- nyvale, CA 94089; Tel. 408-734-2800. RS-232 CONNECTOR KIT. The 272-piece RS-232 Com- mercial Connector Kit from Jensen Tools is designed to simplify on-site fabrication and maintenance of RS-232 cable connectors. It can be used to make straight null- modem hookups and eco- nomical patchcord connec- tions between keyboard and TNC for packet radio, and for many other DB25 patchcord applications. The kit in- cludes 16 plug (male) and 6 receptacle (female) 25-pin connectors, one insertion/ ■i CIRCLE 27 ON FREE INFORMATION CARD extraction tool, 50 cable ties, and a compact plastic stor- age box. Connector hoods are available separately. The RS-232 Commercial Connector Kit costs $69.50.— Jensen Tools Inc., 7815 South 46th Street, Phoe- nix, A2 85044; Tel. 602-968-6231. MULTI-BAND RECEIVER. Providing continuous fre- quency coverage from 25-550 MHz and from 800-1300 MHz, ACE Com- munication's MVT-5000 100- channel hand-held receiver allows reception of civil and military aviation bands plus all public-service bands. AM or narrow FM reception modes are selectable at any frequency. Twenty front-pan- el keys allow programming of 100 scan memory chan- nels. Pairs of upper and lower limits for bands to be searched can be stored in ten separate search memory locations. RAM memory is backed up by a long-life lithium battery. The MVT-5000 offers an energy- saving "sleep" mode, in which the computer will ac- tually power down all operat- ing circuits and display the word "steep" on the LCD, and power up only periodically to check for ac- tive transmissions. The compact radio mea- sures 7x2YzxVA inches and weighs only 13 ounces. It in- cludes a 120-12-volt wall plug adapter/charger, a fused DC cigarette-lighter charger cord, a telescopic antenna, a carrying case, and AA-size re- chargeable batteries. The MVT-5000 hand-held receiver has a suggested re- tail price of $499.00.— ACE Communications, Monitor Division, 10707 East 106th Street, Indianapolis, IN 46256; Tel. 317-842-7115. CIRCLE 28 ON FREE INFORMATION CARD 22 POCKET-SIZE DIGITAL MUL- TIMETER. A.W, Sperry's DM-4200A 3%-digit, rotary- switch digital multimeter of- fers pocket-size portability without skimping on fea- tures. It incorporates nine functions on 33 ranges. The instrument provides a diode- test function, battery test, and HFE transistor test. It fea- tures an instant continuity CIRCLE 29 ON FREE INFORMATION CARD buzzer, a built-in test stand, overload protection, 150- hour battery life, and re- cessed input terminals de- signed for safety. The DM-4200A, which comes with one set of test leads, a battery, and one installed fuse plus a spare, costs $64.95.— A.W. Sperry Instru- ments Inc., 245 Marcus Bou- levard, Hauppauge, NY 11788; Tel. 516-231-7050. PROTOCOL ANALYZER SYS- TEM. Designed for use in troubleshooting asynchro- nous serial data-communica- tions systems, Global Spe- cialties' G5500 portable ana- lyzer has extensive diag- nostic capabilities to assist you in baud-rate analysis, data word format, ASCII or hex data monitoring, and test-data generation. It can operate in both automatic and manual modes, and is small enough for field-ser- vice applications. When it's connected to a standard os- cilloscope, it provides a 32- character display. When combined with the GS501 Display Module and the GS502 Break-out Box, the GS500 is transformed into a complete portable, hand- held system, requiring no oscilloscope. The break-out CIRCLE 30 ON FREE INFORMATION CARD box provides full breaking and patching of 25 lines, plus data monitoring of the ana- lyzer's transmit and receive lines. Using the test-data- generation mode, the sys- tem can be used to check the operation of printers, termi- nals, and other devices when a transmitting device is not available. The battery- powered system will typ- ically operate for 100 hours. The GS500 analyzer, CS501 display, and GS502 break-out box cost $179.95, $99.95, and $119.95, respectively.— Global Specialties, 70 Fulton Terrace, New Haven, CT 06512; Tel. 203-624-3103. HAND-HELD UNIVERSAL TIMER/COUNTER. A 10-digit frequency counter from Optoelectronics incorpo- rates high-speed ASIC and custom LCD technology to provide direct-count fre- quency capability (1-Hz reso- lution in one second) to over 150 MHz. The model UTC 3000 features switched pre- scalers to maximize resolu- tion for frequencies to over 2.4 GHz, and multiple pre- amplifiers for maximum usa- ble sensitivity to allow effi- cient antenna pickup mea- surements. A 16-segment bargraph displays input sig- nal level to ensure reliable counting and to aid in RF se- curity sweeps. Front-panel controls in- clude pushbuttons for gate selection (four gate times), function, and input selec- tion, and also has hold, pre- scale, and direct-count se- lect switches. Calibration and bargraph adjustments are accessible from the front panel, which also features a gate LED and a power switch. In addition to the frequency Cut Your Video Servicing Time by 54%* j**z*+ $3,495 Patented G fAR^ With The Market Proven VA62A Universal Video Analyzer Are you finding it tough to service today's hi-tech VCR and TV circuits? Successful video servicers have told us that, to them, the new technology meant lost profit and troubleshooting grief until they tried the VA62A's time tested, functional analyzing methods. "The VA62A cuts servicing time and increases profits ..." You can prove it to yourself, in your shop, absolutely risk free — and share in the profits successful video servicing can bring. Call 1 -800-SENCORE f7»2«»j and ask about our exclusive VA62A instrument evaluation program. Tech-Tape Video Preview and FREE full line color catalog are also available. "Based on a nationwide survey of users who reported an average time savings of 54% compared to their previous test equipment. 3200 Sencore Drive, Sioux Falls, SD 57107 1 00% American Made CIRCLE 177 ON FREE INFORMATION CARD to to o 23 CIRCLE 31 ON FREE INFORMATION CARD and bargraph display, the custom 120-segment LCD has annunciators for function, gate time, number of cycles averaged, units, and low bat- tery voltage. The UTC 3000's universal timer-counter functions in- clude period, period aver- age, time interval, time- interval average (0.1-ns reso- lution), and ratio. Both 50- ohm and 1-megohm input amplifiers are provided. The overall range is 10 Hz to 2.4 GHz. With its field-installa- ble internal Ni-Cd battery pack (providing up to two hours operation) and its compact size (approximately 4x5fcx1H inches), the unit is highly portable. ATlu-voft, 60-Hz wall plug adapter/ charger is included. Options include four different anten- nas, three probes, a preci- sion 0.2-ppm TXCO time base, a carrying case, and a second parallel battery pack to extend portable operation time. The UTC 3000 hand-held universal counter timer costs $375.00.— Optoelectronics, Inc., 5821 N.E. 14th Avenue, Fort Lauderdale, FL 33334; Tel. 305-771-2050. DIGITAL TRANSISTORS. For use in switching circuits, drivers, interface circuits, and inverters, and for inter- facing with elec- tromechanical systems, the "KSR" series of transistors from Samsung have built-in bias resistors. Eliminating the need for external bias re- sistors in their application CIRCLE 32 ON FREE INFORMATION CARD circuits results in a significant saving of space. There are 28 transistor types — half are NPN devices and half are PNP — available in three different styles of plastic packages. The TO-92 and TO-92S packages have three long parallel leads ex- tending from the bottom. The compact SOT-23 is a plastic surface-mount pack- age with minimal parasitic capacitance and inductance. Its small-outline package has gull-wing-shaped leads for base and emitter on one side and for the collector on the other side. Unit prices are 5 cents api- ece for the TO-92 and TO-92S packages, and 6 cents apiece for the SOT-23 packages, in quantities between 100 and 999. — Samsung Semiconduc- tor, 3725 North First Street, San Jose, CA 95134-1708; Tel. 408-343-5400. INFRARED DETECTOR. While conversion of infrared light to visible light is not new, most converters re- quire batteries or other power supplies for infrared detection. Com/Way Satel- lite Systems' IR Detection Card makes use of a recent technological development to passively detect infrared light. The detector is a busi- ness-card-size device that has transmissive phosphor crystals heat-seai laminated at its center. Those crystals emit an orange glow when subjected to infrared light. 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High-ffiiMily ye Hew AES fine, uifely leu leads C7D tahlei included Res.$l59 MODELS'" MODEL 'n' mvwt O.&S • Range fold • Audible Conlsiiii ily/Diode leu Seg.$U9 Re&$159 Keg.>UV m9 m MODEC 71 • Bo* DC Mtiuocy D.7X Reg.$79 %9 S060A/8062A 4 'A DIGIT HANDHELD ■ 4Vi-digll J 20,000 count display * True-Ems AC voltage and current measurement • Fast audible-visual continuity tests • Relative reference (offset) • Automatic MQ Range Selection * Law-power ohms on all resistance ranges * Cons rant -current diode test mode • Resistance measurements to 300 Mil * Protected from 6kV tran- sients an 660V • One-year warranty /guaranteed calibration MODEL SOaOA MODEL S062A Rett $389 * f rc '1 SJDRt 'p Md dEt * Basic DC actoro-ty: Dims S060A *349 meaiwemeius 12Hz la 20Dfcrli+ • Besk KmamacM% .05% Rea.$329 (289 F CALL TOLL-FREE - SAME-DAY SHIPPING »«*»«' lor facli mh j i At r- r . *i^fl-W: S830 N. Milwaukee Av. Niles, II 60648 - 70S-297-4200 FAX 70S- 297- 6923 M«*nieiMimStt M .e°m°5-0»PB5t ACTIVE AREA TC NDRMAL L IGH " 3EF-CPL USE OETtCTQH WILL EMIT AN aflAMEE GLOW WHIL£ REING EIKSED 10 in ADD VtEWEO IN SUBDUED LIGHT CIRCLE 33 ON FREE INFORMATION CARD UHF POWER TRANSISTOR. Offering outstanding broad- band characteristics and rug- ged packaging, the MRF650 UHF power transistor is Motorola's first RF device to offer guaranteed gain and efficiency specifications at three frequencies — 440, 470, and 512 MHz. Survival is guaranteed for severe load mismatches even when the device is subjected to high supply voltage and input sig- CIRCLE 34 ON FREE INFORMATION CARD nals 2 dB above normal. The transistor is packaged in the popular 6-lead flange. The MRF650 provides 50 watts of output power, high- er than 55% collector effi- ciency, and more than 5-dB gain while operating from a 12.5-volt power supply. Sug- gested applications are in 12.5-volt base-station, com- mercial, and industrial am- plifiers, and as a final ampli- fier in mobile radios. The MRF650 UHF power transistor is priced at $27.75 in quantities of 100 or more. — Motorola, Inc., E-114, 5005 East McDowell Road, Phoenix, AZ 85008. R-E CABLE - TV SIGNAL REA4CVCRS ■FOR ELIMINATION OF SEVERE INTERFERENCE •FOR -CENSORING" OF AOULT BROADCASTS ■" i ■ ATTENUATION - 45 dB TYPICAL ■ BANDWIDTH - 4 MM AT 5 dB POINTS ■ INSERTION LOSS ■ 2 dB MOOEl Tutma flANGE ran CHAMNE13 PAUBAttD price SH-ppms !3H 50-66 MM; 2.3 iv & maw haml 50.300 MH; 130 NO SHIPPING or C.O.D. ■CHARGES «FM ■:■•:;<.'.■• MHz 4 5 5 (or an* FM| 50-300 MHz 130 1417 lHMUMHz •4(A, 1MB) 16 (Clt7(0] 50-400 MHz 130 1622 144-174 Mm 11(E) 1 9(F) M|Glil(H)2S(l) 50400 MHz 130 713 ■:■< ;.■': mhj 78.9 10.11 12 13 S0-4OD MHZ S30 3 for $75 - 1 for $200 - mix or match CALL TOLL FREE FOR CO.D. OR SEND CHECKTO ORDER FAST DELIVERY 30 OAYMONEY BACK GUARANTEE (3 FILTER LIMIT) Star Circuits P. O. Box 94917 Las Vegas, NV 89193-4917 1-800-433-6319 THE HOUSE SITTER THAT DOESN'T NEED A KEY Use the keyboard to set emergency phone numbers, high and Sow temperatures, listen-in time and more ALERT/CANCEL key cancels automatic dial-out, allows you to answer phone WHAT IS key lets you listen to function settings and dial-out numbers "This is 555-3210. Alert condition is OK. Temperature is 65°. Electricity is on. Sound level is OK." Monitoring your home from work or a vacation spot is made easy with the Heath/Zenith House Sitter Security Monitor/ Dialer. Monitors Your Home When you call, the House Sitter will report on the AC electric power, the room temperature - comparing it with high and low limits you've already set, loud noises such as burglar alarms and fire alarms , the unit's own battery backup condition, and an additional alert condi- tion. You can even listen to the sounds in the room using the built in microphone. OI990.H«alh Company Subiidijiy of B utL Dili Sv LlemL Inc. Use the keyboard to ask for information SET key allows you to change previous settings SENSOR ON/OFF key chooses the functions to report ONLY $129.95 Dials Out In Alert Conditions Set the unit to call out to your office, neighbors' and rela- tives' to announce any alert conditions that are outside preset limits. Up to four numbers can be programmed. Order Toll Free 1-800-253-0570 The SD-6230 House Sitter is yours for only $129.95*. To order, call toll-free 1-800-253-0570, VISA, MasterCard, American Express or your Heath Revolving Charge card accepted. Use order code 620-XXX. See our full line of electronic products for your home in the Heath kit catalog - call 1-800-44-HEATH for your FREE copy Heath Benton Harbor, MI 'Price d«e> nol IncliHfc shipping and hwidtl rag. or applicable u]ei IM. C Z m Nov dd and use the Lawn Ranger lor your yard, or even start your own iwh maintenance bus General description The di the Lawn Ran- pie. It c 'I an alumi- num Clltll drive The mi com | minu Now you can sit back and watch your lawn mower cut the grass by itself! Build the Law Range Raymond Rafaels CO o z o £E F O LU _1 LU o o < DC navigation information to the elec- tronic control system. Two 12- volt deep-cycle batteries al- low the Lawn Ranger to operate for approximately 2-3 hours on a single charge. Since the robot is 100% bat- tery powered, there is no need for gasoline, oil, or the periodic mainte- nance associated with gasoline- powered engines . Battery power also allows the Lawn Ranger to run very quiet and clean. Electronic control system The electronic control system is composed of four printed circuit boards; the CPU, motor controller, power, and motherboard. Each board uses readily available off-the-shelf electronic components. The CPU board contains a Z80 mi- croprocessor and is the central "brain" of the Lawn Ranger. The board receives information from grass sensors that are designed to detect the position of cut and uncut grass located beneath the robot. The Z80 micro- processor continually processes the sensor data and calculates the correct steering path for the Lawn Ranger to follow. The motor-controller board is used to control the speed of the drive motors. Velocity information from each drive wheel is fed back to that board in order to keep the Lawn Ranger's speed constant, even when climbing hills. Steering is accom- plished by changing the speed of each rear drive wheel. For example, if the right wheel spins faster than the left, the robot will turn to the left — just like a tank. The motor- con trailer board also contains the circuitry that is used to amplify the grass-sensor signals. The power board contains DC/DC converters that convert the battery voltage to +5-, +I0-, +30-, and — 10-volts DC. The board also con- tains power MOSFET's that are used to control the motors. The motherboard provides the in- terconnection between the boards listed above. Each board plugs into the motherboard via an edge con- nector in order to facilitate the assem- bly and test of the electronic control system. Operation Figure I illustrates the path thai the Lawn Ranger would follow on a typ- ical lawn. The operator must first FIG. 1— THE LAWN RANGER WOULD FOLLOW this path on a typical lawn. The operator must first manually steer the robot around the perimeter of the yard (while cutting grass) and around any obstacles within that area using the manual control unit. manually steer the robot around the perimeter of the yard (while cutting grass) and around any obstacles with- in that area with the manual control unit. The manual control unit is a hand-held device that plugs into the rear of the mower with a 5-foot cable. The initial border cut around the yard is used by the Lawn Ranger for navi- gation, as it will steer along the border while it cuts grass. Because the mower will search for high grass, it will move away from any area that has been previously cut. That feature al- lows the robot to move around trees and other obstacles that are sur- rounded by cut grass. After all the borders are cut, you unplug the man- ual control unit, switch the mower into its automatic mode, and then watch it finish the job as you relax and enjoy a cold drink ! Safety There are several safety features that have been added to the robot in addition to the shut-off switches. There are special cutting blades (see Fig. 2) that freely pivot at the end of the round blade disks. The centrifugal force created by the spinning disks causes the blades to swing outward where they will hold their position while cutting grass. But if the blades hit a solid object, they will give, thus reducing the cutting force and risk of serious injury. However, even with that feature, the blades are extremely dangerous and should be treated as such. Warning: just like any lawn mower, never leave the powered unit unat- tended. Also, make sure that an adult is always present while the mower is in operation. Always keep hands and feet away from the mowing deck, and make sure cutting area is free of peo- ple, animals, and debris. Never let children or animals ride on top of the robot. Grass sensors A close-up shot of the grass sensors is shown in Fig. 3, As you can see, the sensor consists of two protruding plastic prongs that contain an infra- red light source (an IR LED) and a detector (a photo transistor). Fifteen of those sensors are placed in a row across the front of the Lawn Ranger. A partial schematic diagram of the sensor assembly is shown in Fig. 4. The sensors are spaced approximately 2 inches apart as measured from the center of each sensor. The LED's of each sensor are con- nected in series. Light from each LED will cause its respective phototran- sistor to conduct and the emitter volt- age to rise to +5-volts DC. When a piece of tall grass passes between an LED and detector, the phototransistor will stop conducting and the emitter voltage will change from a digital "1" 32 FIG. 2— THERE ARE SPECIAL CUTTING BLADES that freely pivot at the end of the round blade disks. will remain at +5 volts. The digital information from each sensor is sent to the motor-controller board for am- plification and then forwarded to the CPU board for processing. Computer program The computer is used to locate the position of the cut-grass border as it passes beneath the mower. The loca- tion of the border will allow the lawn ranger to decide if it should steer left, right, or straight ahead. As each grass sensor detects grass, it will output a digital "1" (high grass) or a "0" (cut grass or no grass). The computer will sample every sen- sor several times per second, and then store the information in memory. Ta- H il ii H FIG. 3— THE GRASS SENSORS contain an infra-red light source and a detector. SENSOR 1 — SENSOR 2 FIG. 4— SCHEMATIC DIAGRAM of the grass-sensor assembly. SENSOR 3 ( + 5 volts) to "0" (0 volts). Since cut grass is not tall enough to pass be- tween the sensors, the sensor outputs ble 1 illustrates a memory dump that contains five samples of grass-sensor data. In Table 1 , the actual edge of the cut-grass border is located between sensors 8 and 9, with tall grass posi- tioned between sensors 1-8, and cut grass between sensors 9-15. The tall- grass region (sensors 1-8) will record a large number of 1 's as the tall grass flows through the sensors (l's will periodically be recoded in the cut- grass region due to stray uncut blades of grass). In order to calculate the correct po- sition of the cut border edge, the com- puter program will add the number of "1" tallies for each sensor. If the number is greater than or equal to 2, the computer will store the final value of 1 . If the summed value is less than 2, then a value of is stored. For example, the final value stored for the first five data samples in Table 1 would be 111111110000000. Now, it is very easy to detect the location of the grass border. It is simply identified by the point where the string of l's end. A simplified flow chart of the comput- er program is shown in Fig. 5. CPU board Figure 6 is a schematic diagram of the CPU board. The CPU board is responsible for processing the sensor data and calculating the correct steer- ing direction. It consists of a Z80 mi- croprocessor (IC1), two parallel I/O chips (IC9 and IC10), a 4Kx 8-bit EPROM (IC6), two 4K x 4-bit RAM chips (IC7 and IC8), and glue logic (IC2 through IC5). The CPU was chosen in order to keep the parts cou- nt low and the price within the budget of hobbyists. The clock for the Z80 is generated by three inverters contained on IC2. A 2-MHz crystal is used to ensure that a steady timing frequency is main- tained over ambient temperature changes. The clock output (pin 6 of IC2) is tied to the Z80 microprocessor and to pin 25 of IC9 and IC10. Power- on reset is accomplished with an RC delay circuit made up of R4, C12 along with IC5-d, which is used as a buffer for the delay circuit. The rst line will reset two latch circuits upon power up. The first latch circuit consists of IC4-a, IC4-b, IC3-b, and IC3-C, and the second circuit by IC4-C and IC4- d. The latches are used to store the start and full stop signals. Those signals command the Lawn Ranger to move forward and turn off, respec- tively. When the robot moves for- c z m to O 33 TABLE 1— GRASS SENSOR DATA Sample # Byte 1 Byte 2 Sensor # 12 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 11010101 0100010 10111111 00 00000 01001110 1000100 10100111 0000000 010 10010 0000000 ward, the start signal will turn Ql on and bring the stop move line low. When the robot shuts down , pin 8 of IC4-c and pin 6 of IC3-d will go low. That deactivates the input power relay. Input/output The CPU board uses two Z8420 parallel input/output or PIO chips ta- rn o z 8 I 6 < EC DETERMINE FINAL TALLY FOR EACH SENSOR (1 OR 0) LOCATE POSITION OF GRASS BORDER EDGE SEND STEERING INFO TO MOTOR CONTROLLER BOARD X FIG. 5— SIMPLIFIED FLOW CHART ol the computer program. beled IC9 and IC10. Each chip has two 8-bit I/O ports that are software programmable. Bit 7 of Port B on IC10 is programmed as an output. That output line provides a gating pulse that is used to sample the sensor data. When the line goes high, the sensors are enabled and sensor infor- mation is passed to the motor-control- ler board for amplification. After the sensor data is amplified, it is sent to 1C10 on the CPU board. The bits of Ports A (0-7) and B (0-6) of IC10 are defined as inputs that are used to receive the sensor data. IC10 transfers the information to the Z80 microprocessor over the data bus for processing. CPU construction and test It is recommended that you use a PC board for the CPU, and you can either purchase one from TSI (it's a plated-through board that's hard to make — see ordering information) , or you can make one from the artwork provided in PC Service. Also, the 2732A EPROM is preprogrammed and is available only from TSI. Using the parts-placement diagram of Fig. 7, first solder the IC sockets to the board, then solder the remaining components. Then, carefully push all the IC's into their respective sockets. And remember, that some of the IC's are CMOS, which must be handled carefully. Figure 8 shows a fully as- sembled CPU board. Apply + 5 volts to TP4 and ground to TP6. Place a scope probe at pin 34 of IC10; the scope should display a 1- kHz square wave. If you don't have a scope, verify that the voltages on pins 9, 10, If, 13, 14, and 15 of IC9 read 0- volts DC. Now, as you temporarily ground pin 15 of IC10, recheck IC9 for 5 volts on pinsJO, 13, 14, and 15, and volts on pins 9 and 12. If your board passes those tests, it All resistors are Vi-watt, 5%, less otherwise indicated. R1.R2— 1000 ohms R3-R7, R12, R15, R17— 2200 ohms R8 — not used R9, R10, R19, R20— 3300 ohms, SIP R11, R18— 3300 ohms R13— 22,000 ohms R14— 470,000 ohms R1 6-^7,000 ohms R21— 120 ohms Capacitors C1.C12— 100 ixF, 25 volts, electrolytic C2, C3, C5-C9, C11, C13, C15. C16, C18— 0.1 fiF, ceramic C4 — 56 pF, ceramic C10— 10 jjlF, 16 volts, electrolytic C14 — not used C1 7 — 1 p.F, 35 volts, electrolytic Semiconductors IC1— Z84CO0-4PS microprocessor IC2— 74HCT04 hex inverter IC3— 74LS08N quad 2-input AND gate IC4— 74LS00N quad 2-input NAND gate IC5— 74LS32N quad 2-input OR gate IC6— 2732A 4Kx8 EPROM (must be purchased from TSI) IC7, IC8— 2114L-21Kx4RAM IC9, IC10— Z84C20-4PS parallel I/O D1—1N41 48 diode Q1— 2N3904 NPN transistor Other components XTAL1— 2-MHz crystal J5 — 10-pin IDC connector S1 — 7-position DIP switch TP1-TP6 — individual pins or scraps of component leads Miscellaneous: IC sockets Note: The following items can be purchased from Technical Solu- tions, Inc., P.O. Box 284, Damascus, MD 20872 (301) 253-4933: PC boards for the CPU, motor-controller, power board, and motherboard, $39 each; programmed EPROM, $39 (contains computer program and firmware license); grass sensors, $8.99 each; hand-held manual controller kit, $39; full CPU-board kit, $129 (includes EPROM, PC board, and all parts); full kit for motherboard, $69 (contains PC board and all parts); kit for power board, $149 (contains PC board and all parts except DC/DC converters); full kit for motor-controller board, $169 (includes PC board and all parts); Lawn Ranger demo VHS tape, $19 (refundable for orders of $100 or more). Please add $8.00 for S/H (U.S. orders). Mary- land residents add sales tax. 34 33 FULL STOP POWEfl *t_OK(OFF 40 STWMffrt ■ : m i BUS+ 066t 3Nnr 36 Electronics Engineers & Designers! Take 3 books for only $ 3.95 (Values to $168.40) SHARPEN YOUR SKILLS— With Quality, Affordable Professional Books COMPUTER SCIENCE II Computer "fools. 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Con- tains hundreds of informative illustrations and diagrams demonstrating key princi- ples. 600 pp. Counts as 2 How the Club Works: SEND NO MONEY NOW! YOUR BENEFITS: You get 3 books for $3.95 plus shipping & hand- ling when you join. Yon keep on saving with discounts of up to 50% as a member. YOUR PROFESSIONAL BOOKSTORE BY MAIL: Every 2>A weeks, you will receive the EE&D Book Club News describing the Main Selec- tion and Alternates, as well as bonus offers and special sales, with scores of titles to choose from. AUTOMATIC ORDER: If you want the Main selection, do nothing and it will be sent to you automatically. If you prefer another selection, or no selection at all, simply indicate your choice on the reply form provid- ed. You will always have at least 10 days to decide. As a member, you agree to purchase at least 3 books within the next 2 years and may re- sign at any lime thereafter. BONUS BOOKS: Starting immediately you will be eligible for our Bonus Book Plan with savings of up to 80% off publishers" prices. IRONCLAD NO-RISK GUARANTEE: If not satisfied with your books, return them within 10 days without obligation! EXCEPTIONAL QUALITY: All books are quality publishers' editions especially selected by our Editorial Board. All boons are hardcover unlosa number i* lotlewad bv a £11 W« EEDBC Bluo Ridgt Summu. PA 17294-0S6C ■P" tc* papwback. IPubtithert' Prtcei thownj INTRODUCTORY 10-DAY FREE EXAMINATION ELECTRONICS ENGINEERS & DESIGNERS BOOK CLUB SM Blue Ridge Summit, PA 17294-0860 DYES! Please accept my membership in the Electronics Engineers & Designers Book Club and send my 3 volumes listed below billing me S3. 95. If not satisfied, I may return the books within 10 days and have my membership cancelled. I agree to purchase 3 or more books at regular Club prices during the next 2 years, and may resign at any lime thereafter. A shipping/handling charge and sales tax will be added to each order. Name Address City State Zip Phunc Signature Valid lor new members only. Foreign applicants will receive special ordering instruc- tions. Canada must remit in U.S. funds. This order is subject lu acceptance by the Electronics Engineers & Designers Book Club. 0RE690 C Z m _L CO CO o 39 TF1 TP2 1P3 TP4 TP5 TP6 Q 9 O Q Q FIG. 7— ASSEMBLE THE COMPONENTS according to this parts- placement diagram. CO o z o DC h- O LU o a < DC FIG. 8— FULLY ASSEMBLED CPU BOARD. should be functioning properly. More extensive testing of the CPU can be performed after the motor controller, power board, and motherboard are as- sembled and tested. Still to come In the next couple of issues of Ra- dio-Electronics we will explain how you can finish building the Lawn Ranger. As far as the electronics portion goes, we've still got to build the motor-controller board , the power board, and the motherboard, which holds all of the other boards together. Then we have to build and wire the sensor assembly, put together the me- chanical frame, and connect every- FIG.9— THE COMPLETE LAWN RANGER unit. We will get to the mechanical assem- blies in later issues. thing together. By the way, for a sneak preview look "under the hood," of what the Lawn Ranger will eventually look like, Fig. 9 shows the complete me- chanical assembly, without the cover. "Vbu can see that everything fits to- gether in a nice, compact package. For those of you who still doubt the Lawn Ranger's capabilities, a VHS demo tape can be purchased, showing the unit in action; it's sure to make you a true believer. The cost of the tape is refundable with an order (see the Parts List for details). R-E 40 BUILD A GENERIC LINEAR POWER SUPPLY BOARD Why go through the trouble of designing a custom power supply every time you build a new project? This single PC board can fill all of your power-supply needs! JOHN WANNAMAKER ARE YOU TIRED OF LAYING OUT YET AN- other PC board for some special power supply? Here's a possible solu- tion to lessen the trauma: the EZ-DC generic power-supply PC board, de- signed to give you a choice of one or two linear supplies on a single 2x3- inch PC board. The layout is very versatile, and while one supply pro- duces a fixed-positive voltage, the other can have any value desired. The choices are: • Two fixed-positive supplies. • One fixed-positive, and one ad- justable-positive supply. • One fixed-positive, and one fixed- negative supply. • One fixed-positive, and one ad- justable-negative supply. Of those configurations, the sup- plies can be either half-wave or full- wave, when a transformer with a cen- ter-tapped secondary is used, or you can build a single full-wave bridge of either polarity. You can also make il adjustable or not, as you prefer. Dual isolated grounds are possible . For the TO- 220/221 A regulators, there are four different 3-terminal pinout con- figurations, which made the layout of the EZ-DC quite challenging. Whether or not to rotate the regulator 180° helped reduce the reconfigura- tion problem to one of selective place- ment of jumpers. The EZ-DC is a good basis for a bench supply. With two PC boards, you can build two fixed-positive sources, an adjustable-positive source, and an adjustable-negative source, all with or without isolated grounds. Each supply provides for a milliammeter to be inserted at its reg- ulator input. In one supply on each PC board, the meter replaces a jumper. In the other, two adjacent pads are provided for meter leads. The foil connecting the two pads has to be cut with a razor blade or X-acto knife to use the meter; the point is marked by an arrowhead and an "X." Different power-supply types • Separate fixed-positive full-wave supplies with common grounds. Figure 1 shows a dual, full-wave, fixed -positive supply, using a com- mon ground. Fig. l-a shows the pi- nouts of the two regulators, Fig. l-b shows the schematic, and Fig. Uc shows the parts placement diagram. Supply #1, on the lower half of the PC board, is always fixed positive. Supply #2, on the upper half of the PC board, can be varied in configura- tion, and is, in this case, also fixed positive. Since the center-tapped transformer supplies equal voltages to each regulator, the most efficient ar- rangement is for both IC's to regulate to identical (or nearly so) voltages, such as + 12 and + 15 volts. Where the difference is considera- ble, as between a + 5- and a + 12-volt supply, the lower voltage regulator must drop 7 volts more than the higher one, and its load current must be lim- ited accordingly. Since the voltage drop across the regulator is multiplied by the load current to determine the regulator power dissipation, the lower the voltage, the more current that's available. The less power consumed by the regulator, the more that's avail- able to the load. However, there has to be some drop across the regulator or it won't work. This is nominally 2 volts for the 78XX/79XX fixed- voltage series, and about 2.5 volts for the LM317/ LM337 adjustable models. Also, the regulator needs a standby current of c 2 m CD g 41 120VAC* WO— i IOOOhF ■-►Hi D3 „ »| i CI IC1 78XX GND tL C2 - COMMON ~° GROUND FIG. 1— A DUAL SUPPLY, WITH TWO fixed-positive sources. The pinouts of 1C1 and IC2 are shown in (a), the schematic is shown in (b), and the parts placement diagram is shown in ( c), with supply #1 on the bottom, and supply #2 on top. This same order of ia)-(c) is used throughout all succeeding figures, except Figs. 4 and 7. 3-10 miliiamps, ignored here. Expect any current monitoring at the pro- vided points to reflect this error. A milliammeter would be inserted in supply #2 in place of jumper JU1, with the negative terminal connected nearest to the heatsink when monitor- ing a positive supply. In supply #1, connect the meter to the two pads near the right wing of the lower heatsink. Cut the foil between these two pads at point X as already mentioned. The negative meter lead goes to the pad HEAT SINK nearest to IC1 . Two pads V and W on both PC board and schematic are un- used here. Extra filtering capacitance can be added here for supply #2, or these points can provide unregulated voltage for noncritical circuits. Pay attention to the polarity at point V which depends on the polarity of sup- ply #2; point W is ground. • Separate fixed-positive and fixed-negative fuli-wave supplies. In Fig. 2, supply #1 is fixed- positive as before. The difference is how supply output « TAB IC1 73XX OUTPUT #1 C4 + \ oG3 ffl z a fe - z 2 02 J* l r&J V( 4 1 120VAC; in O z o & :_l _l HI 6 Q < rr D3 D1 V,' £ ci IOOOjiF GND ca 10nF ^COMMON "° GROUND FIG. 2— A DUAL SUPPLY, WITH SEPARATE fixed-negative and fixed-positive sources. The organization of (a)— (c) is that of Fig. 1, but supply #2 has been made negative by reversing D2, D4, C3, and C4, and using a 79XX for IC2 in stead of a 78XX. #2 is jumpered, to accommodate a fixed-negative regulator, like the 79XX/79MXX series; the "M" de- notes medium -power versions, which are harder to find. Since load currents of less than 500 miliiamps are sug- gested to prevent overheating, you should try to find the "M" versions, if possible. Again, due to the trans- former's equal voltage distribution, equal but opposite polarity regulators would be most efficient. Some gener- al information on selecting the trans- former will be given later. • Separate fixed-positive and ad- justable-positive half-wave sup- plies. Figure 3 shows supply #2 with an adjustable regulator in a half- wave configuration, where both it and the heatsink are rotated 180° from the fixed regulator position. Don't use this version in applications where the load current exceeds 200 miliiamps. Extra capacitance at V and W will give a smoother input to the regulator, but strains the transformer and diodes due to the higher half-wave charging currents. The accompanying table in Fig. Z-d shows V 2(MAX) , for different values of Rl and R2. While current demands could be excessive, the voltage distribution with this arrangement may be advan- tageous. With one end of the winding grounded, the center tap supplies modest voltage for a low- voltage fixed supply, and the other end provides double that voltage from the adjusta- ble supply. Where higher current is required, the diode and transformer arrangement shown in Fig. 4 is sug- gested instead. • Separate fixed-positive and ad- justable-positive full-wave sup- plies. The more features you want in any piece of equipment, the more it's going to cost, and the EZ-DC is no exception. The best transformer ar- rangement, shown in Fig. 4, uses two transformers with center-tapped sec- ondaries, or a single transformer with dual center-tapped secondaries, if you're able to find one. The relevant segment of schematic is shown in Fig. 4-a, and the relevant segment of the parts placement diagram is shown in Fig. 4-6. Supply #1 always has the layout shown in Fig. 1, and you can take the layout for supply #2 from any other version you prefer, in any of the fig- ures. For example, copy the upper part of Fig. 2 for a fixed-negative sup- ply (remember to reverse D2 and D4), 42 HEAT SINK OUTPUT *1 IPOS.) + ;, a- W o oG3 V o + + -C3- -Rl- + | IC2 C5| | VARIABLE COS, ADJUST -o- 0UTPUT« (VARIABLE POS.I o + Bl R2 v | 22011 2K 12.6 V 20011 2 K 13.8 V ISO!! 2K 15.2 V 15011 2K 17.9 V 12011 2K 22.1 V 27011 5K £4.4 V 22011 5K 29.7 V TOUT m«: C4 _Lf 10nF*" R2 I 1 C2 IDttf FIG. 3— A DUAL SUPPLY, WITH SEPARATE fixed-positive and adjustable-positive sources. Supply #2 is now made adjustable-positive, changing the jumpers as indicated, changing IC2 to an LM317, adding potentiometer R2, and shifting the other parts as shown. Also, only D1 and D2 are used, and the secondary of T1 is rewired. The accom- panying table in (d) shows V 2(MAX) , for different values of R1 and R2. FIG. 4— DUAL FULL-WAVE RECTIFICATION for a fixed-positive supply #1, using either two single-secondary transformers, or a single dual- secondary version; (a) is the rele- vant segment of schematic, (b) is relevant segment of the parts placement diagram. Only the lower half of the PC board (supply #1) is shown ; you can design the upper half (supply #2) as you wish. For example, copy the upper half of Fig. 3 for an adjustable-positive supply, or the upper par of Fig. 5 if you want an adjustable-negative dupply (remember to reverse D2 and D4). or the upper part of Fig. 3 for an adjustable-positive supply, or. If you'd rather calculate your own val- ues than use those provided in the table accompanying Fig. 3, use the following formula: V 2 = 1.25 volts x[1 + (R2/R1)]. For best results, keep: RK240 ohms. There's no way to control the minimum output, which should be about 1.25 volts. • Separate fixed-positive and ad- justable-negative half-wave sup- plies. A version with dual half-wave supplies, one fixed-positive and the . OUTPUT *1 VAR. POS. -DOUTPLrm COMMON GROUND other adjustable-negative, is shown in Fig. 5. It's got the same limitations as the version shown in Fig. 3. For the greater current a full- wave supply can provide, use the rectifier arrangement shown in Fig. 4 (reversing D2 and D4), with the layout shown in Fig. 5. If you use a transformer with no cen- ter tap, Dl is connected as shown by the dashed lines. In that case, jumper pad 3 to pad 5 with JU7, and remove the connection to pad 6. The output pad is closer to the heat- sink than you might prefer, but all patterns have multiple output points. Examine the foil pattern and select your own output pad. Always select a ground nearest the filter capacitor's ground connection to minimize hum, and use separate grounds for each supply. • Separate fixed-positive full-wave supplies with isolated grounds. The arrangement for isolating the grounds between full-wave recitifiers is shown in Fig. 6. While this version has dual fixed-positive supplies, that needn't be the case. Use any version for sup- ply #2 you want, but watch the diode polarities. Cut the foil at the "Z" by the ground foil, and then the trans- former secondary pads, isolating 3 from 4, and 5 from 6. Arrowheads on the foil side show the exact points to cut. If you connect the supplies in series, the total output voltage is the sum of both. \bu can assume both regulators to be passing identical currents, but not necessarily dissipate the same power, since their regulator drops may differ. c z m CO g 43 HEAT SINK TAB PUT#1 O- (POS.i W V JU2 ^"^ VARIABLE NEC, 1 ADJUST -m- 05 CUT FOIL TO 6 SEPARATE 5 FROM 6 IF J7 IS ADDED woJ> J4 . C3 1000mF IC2 LM337 IC1 78XX ft "= ? R1 04 ± 10jiF ADJ. C5 10nF :i =oOUTPUT#2 IVARIABLE NEG.) O OUTPUTS ;R2 C2 ; -o OUTPUT*! ,-COl ^ GROUND FIG. 5— A DUAL SUPPLY, WITH COMBINED fixed-positive and adjustable-negative sources; it has the same limitations as Fig. 3. For greater current, use the full-wave approach of Fig. 4, with the layout shown here. The D1 shown using dashed lines is connected this way for a transformer with no center tap. In that case, jumper pad 3 to pad 5 with JU7, removing the connection to pad 6. HEAT SINK TAB CUT FOIL TO SEPARATE 3 FROM 4, AND 5 FROM 6 OUTPUTS CUT {POS.) GROUND OUTPUT #2 (POS,) O z 1 U HI -I w 6 5 < FIG. 6— TWO SPLIT-GROUND fixed-positive full-wave supplies. You can use any other version you want for supply #2, but watch the diode polarities. With a razor blade or X- acto knife, cut the ground foil at the "Z." Then, cut the transformer secondary pads at the arrowheads, isolating 3 from 4, and 5 from 6. If you connect the supplies in series, the total output voltage is the sum of both. Assume both regulators pass identical currents, but don't necessarily dissipate identical power, since their regulator drops may differ. • A single full-wave bridge supply. The connections for a full-wave bridge are shown in Fig. 7. Figure 1-a shows the relevant segment of the schematic, and Fig. 1-b shows the relevant segment of the parts place- ment diagram. Don't forget JUS where an electrolytic would normally go. Again, use the top of the PC board for any version, whether positive, negative, fixed, or adjustable — but note the the diodes are shown for a positive supply and must all be re- versed if yours is negative. • Separate fixed-positive and ad- justable-positive supplies from a car battery. Figure 8 assumes that you use a standard + 5-, + 6- , or + 8- volt regulator for IC1 , and an adjusta- ble version for IC2; the output of the second regulator is adjusted by R 1 and R2. The accompanying table in Fig. %-d gives V 2 to within 50 millivolts for different values of Rl and R2, but you can also use the previous formula. The PC board layout To ensure that the wide ground foil holds hum to under 1 millivolt, the best soldering layout was sacrificed; you may need to use more heat and solder than usual. Use 4-40 or 6-32 machine screws in the corner holes for mounting. One corner is attached to the ground foil as a metal spacer to electrically connect the PC board to a metal chassis. If you don't want to use it, cut it away. The heatsinks are electrically con- nected to the middle pin of each reg- ulator. For a fixed-positive model, it's ground, but it's different in each case; for example, it's the unregulated input in the adjustable-negative model. A little heatsink silicone grease will help transfer about 20% more heat, and can be worthwhile — especially if the regulators are sourcing very high c urrent. If you use the recommended heat- sinks with the three through-the-PC board tabs, be careful you don't bend them underneath and cause a short. Space was left hoping to avoid this, but watch it. The regulators are fairly close to the edges of the PC board to possibly heatsink to a metal cabinet with a screw. Measure the tab's poten- tial, to be sure it's grounded, and use insulation if needed. If you want full 1-A load current, use a fan. Selecting components Don't consider the following the last word on how to select power- sup- ply parts. This is an abbreviated meth- od to keep you from going very wrong with practical advice from personal observations. The transformer is a good starting point because they're "iffy," at best. Consider the second- ary voltage; for example, a 10- volt secondary. With little or no load, you may measure up to 12 volts. If the line voltage is 5% high, you'll measure 12.6 volts. Isn't that reasonable with 44 FIG. 7— A FULL-WAVE BRIDGE RECTIFIER as supply #1; (a) is the relevant segment of schematic, (fc> is the relevant segment of the parts placement diagram. Remeber to reverse D1-D4 for a fixed' negative version. The connections for a full-wave bridge are shown in Fig. 7, and don't forget to add JUS. You can also make supply #2 on top any version, whether positive, negative, fixed, or adjustable. the peak transformer voltage is per- ceived by the electrolytic. Close to rated current, a diode drops about 0.8 volts, and 0.5 volts at low currents. Since the diode normally conducts to recharge the electrolytic, assume a worst-case drop of 1.2 volts. This is the figure to use with either half-wave or full- wave center-tap. With a bridge, two diodes conduct in series, so two drops must be added , for a worst-case of 2.4 volts. The electrolytic perceives the sec- ondary voltage, minus the diode drop{s). Unless you're right on the -o+ 0LrrPUT#l ■Sr S ?fc *<&***** s*n 5®' W$Sf*»*V* CIRCLE 108 ON FREE INFORMATION CARD isn't constant. The average input volt- age varies with load current, and the ripple voltage increases in peak-to- peak value with current. At its lowest value during worst-case ripple, the regulator drop must be at least 2 volts. The following formula for the mini- mum required electrolytic size in u.F is a good approximation: C filter = 6000xl load /V rippple . For example, if maximum load cur- rent is 0.5 amp, and ripple voltage is 2 volts P-P, the minimum electrolytic size is: C, ilt = 6000 x 0.5/2 = 1500 jjlF This is valid for full-wave, but needs to be doubled for half- wave. Now, work backwards, from output back to transformer, to determine the minimum peak voltage the trans- former has to deliver. For now, ignore any over- voltage condition, since that's mainly important in determin- ing the electrolytic 's voltage rating. Starting with the desired regulated output voltage, say + 12 volts, add up all the voltage drops present: 12.0 volts regulated output 2.0 volts minimum regulator drop 2.0 volts P-P ripple (somewhat arbitrarily selected) + 1.2 volts worst case diode drop 17.2 volts minimum peak voltage from transformer secondary Multiplying this sum by 0.7071 gives 12.16 volts, the minimum toler- able RMS secondary voltage. This works well with a normal 12. 6- volt secondary, but with only a 3% cushion for a low line-voltage con- dition. With the extra voltage the transformer provides, it should be efficient — for a linear supply. If the figures are too high for a standard transformer, consider using extra ca- pacitance to achieve smaller ripple. If you can select the transformer from several already on hand, or can afford a little extra cost, a transformer with twice the anticipated current rat- ing could mean an extra volt or more in the secondary voltage. A higher secondary voltage will manifest itself as a higher regulator drop, causing more heating for any given load. This problem is insoluble when using an adjustable regulator to provide from 1.25-25 volts. A clean 27 . 5 volts would have to be available at the regulator input to ac- commodate the highest output. How- ever, when adjusted downward to only 2 volts, the regulator drop increases to 25.5 volts. Output current must be reduced to prevent overheating. Finally, here's a little information on the TO-220 regulators. While the adjustable models can handle some- what higher voltage, consider 35 volts as a maximum for all. This includes the fixed versions from 5—15 volts, inclusive. This same 35-volt figure was kept in mind as a capacitor rating when considering component sizes. The regulators protect themselves by automatically shutting down when overheated, and by current limiting when shorted. This limit may still be enough to damage the transformer and diodes, "iou can consider a reg- PARTS LIST un> 8) All resistors are 1 /4-watt, 5%, less otherwise indicated. R1— 150-270 ohms (see Figs. 3 and 8} R2— 2000- or 5000-0 hm cabinet mounted potentiometer R3— 270-1500 ohms {see Fig Capacitors C1, C3, C6— 1000 u.F, 16 volts electrolytic C2, C4, C5— 10 jiF, 30 volts, electrolytic Semiconductors D1-D4— 1N4004 or 1N5404 silicon rectifier diode or equivaient IC1, IC2— 78XX, 79XX, LM317, and/ or LM337 3-terminat TO-220 volt- age regulators (see text) Miscellaneous: one or more copies of the PC board (see PC Service), suitable cabinet, red and black ba- nana jacks, one or more 3-terminal regulator heatsinks (JAMECO part number 6030F3), '/32-incri and Ms- inch drill bits, wire, solder. ulator as a I.5-watt device with no heatsinking, a 5- watt device with fair- ly good heatsinking, and a 12-watt device with excellent heatsinking and air circulation. To get a rough idea of safe opera- tion, let one operate under worst-case conditions for five minutes, and then applying a tiny drop of room-temper- ature water to the top of the its heat- sink tab. Even if a heatsink is attached, apply the water only to the top of the tab— awkward, but possi- (Continued on page 58) ~ "~L .tjl - ■ - 7y > G_ BUILD THIS PROGRAMMABLE CRYSTAL-CONTROLLED PULSE GENERATOR PXO-IOOfi (8428) Build a single-chip pulse generator using a programmable crystal oscillator IC. UNTIL RECENTLY. BUILDING AN INEXPEN- sive, calibrated frequency source has generally involved dividing the out- put from a crystal oscillator to the specific frequency desired. Figure I shows a 1-MHz crystal oscillator feeding a series chain of TTL decade counters to illustrate the technique. A significant improvement is pro- vided with the recent advent of the Statek Corp. (512 N. Main St., Or- ange, CA 92668) PXO series of Pro- grammable Crystal Oscillators. These are hybrid IC's with on-board crystal oscillators mounted in 16-pin DIP's, drastically reducing the total PC board space and power required. All members of the PXO series are identical internally, differing only in the base crystal frequency. The user can select any one of 57 different fre- quency-divider ratios, using two in- ternal, series frequency counters, each with three TTI^compatible ex- ternal taps for setting the divider ratios . Figure 2 is a block diagram of the PXO- 1000; it has an a 1-MHz internal crystal, and two internal programma- ble frequency dividers, with ratios available to let the user select output frequencies ranging from 0.0083 Hz-1 MHz. The IC was also made with provision for using an external PETER A. LOVELOCK source to provide a base frequency that differs from any of the standard manufactured values of the PXO chips. These IC's also allow either com- puter control of the frequency se- lected, by varying the logic levels of the taps, or manual control using ei- ther DIP or rotary switches. The PXO- 1000 has ± 100 ppm accuracy and ±0.015% stability at room tem- perature, and consumes only 3.5 mil- liwatts, or 0.7 milliamps at 5 volts DC. The other standard available base crystal frequencies are 326.68 kHz (the PXO-32768), 600 kHz (the PXO-600), and 768 kHz (the PXO-768). The PXO-1000 The drawback to the divide-by-N counter shown in Fig. 1 is the need for eight separate counters and a separate crystal oscillator. If 7490 divide- by- 10 counters are used, the circuit will take up about 7 square inches on a PC board, and draw 45 milliamps at 5 volts DC for each IC. Thus, the dividers draw P = IxE = 8x45x5 volts DC = 1.8 watts, and the os- cillator an additional 0.1 watt, a total of 1.9 watts, a load that makes battery operation impossible. By contrast, the PXO-1000 shown in Fig. 2 uses under I square inch of PC board real estate, and only 3.5 milliwatts — perfect for battery opera- tion. The output is available on pin 11 (f OUT ), and the external clock for special cases can be applied to pin 12 (exc). Both clocks are fed to the clock-select logic, allowing selection between either one depending on the state of pin 13 (csel), the internal clock if low, the external clock if high. The output of the clock-select logic feeds the two internal programmable counters. They're in series, so the total frequency division factor is the product of the two . The first can be set to divide by I, 2, 3, 4, 5, 6, 10, or 12, while the second divides by a power often, ranging from 1-10 7 , inclusive. There are eight possible settings for each, since there are three control bits for each and 2 3 = 8. If all the divider ratios were unique, there' d be 8 x 8 or 64 distinct frequency divider settings possible. However, since both the first and second counter can divide by 1 and 10, seven of those 64 factors will be duplicated. The PXO-1000 is programmed using pins 2-4 (P 3 P 2 P|) and pins 5-7 (P 6 P 5 P 4 ); these are the frequency counter control bits. Setting any of them to V cc constitutes a logic high, c z m i o 47 1MHz 100kHz 10kHz 1kHz 100Hz 0.1Hz 0.01Hz FIG. 1— GENERAL PURPOSE PULSE GENERATOR needs a 1-MHz crystal oscillator driv- ing a chain of high-power TTL decade counters like the 7490 4-bit decade counter. «— cr o OFF SI OH EXC CSEL RESET B1 4.5VDC (3 aa or aaa alkali ne cells) — — tH'IHi-tl IC1 PXO-1000 TJ CSC CLOCK SELECT TEST " — 1 " IC1 ,| — I < < PXO-1000 * 1/1 - 1/12 PROGRAM DIVIDER L'1-1/10' PROGRAM DIVIDER OUT -& -<^------%; D 6 6 6 6 6 6 DIP SWITCH S2 FIG. 2— BLOCK DIAGRAM OF PXO-1000 IC programmable frequency divider with internal 1-MHz quartz crystal oscillator. Frequency division ratios are selected by setting DIP switch S2; 57 distinct frequencies in the range from 0.0083 Hz-1 MHz can be generated. Each of the SPST switches a-f in S2 control a single bit from among pins 2-7 (P 3 P 2 Pi and P6P5P4). the select lines for the two counters. Here, a +4,5-volt DC supply using B1 provides power. w o z o rr b m _i 111 g Q < FIG. 3— ROTARY SWITCHES AND DIODE MATRIX D1-D18 set the frequency counters of the PXO-1000, eliminating: DIP switch S2 in Fig. 2. D1-D18 act to block incorrect bits from among pins 2-7 (P 3 PzP-i and P 6 P 5 p4) from being set high. D1-D9 acts with S3 to control P1P2P3. while D10-D18 acts with S4 to control P 4 P 5 P 6 . S1, the ON/OFF switch, and J1, both present in Pig. 2, have been omitted, but would be needed here. and ground to a logic low. The fre- quency division effect of pins 2-7 (P ? P 2 P| and P 6 P 5 P 4 ) is summarized in Tabic l . The settings of pins 1-A ^PjP^ aren't in directly ascending order for the first counter. At the low end, the frequency division factor jumps from 1 for a setting or 000 to 10 for 001, and back down to 2 for 010, while at the high end, the factor jumps from 6 for 110, to 12 for 111. However, the set- tings for pins 5-7 (P 6 P 5 P 4 ) do go in order, and the binary number corre- sponding to these three bits is the ex- ponent of the power of 10 for the frequency division factor involved. Thus P 4 P 5 P 6 = 100 is binary for 4, or a division factor of 10 4 . If the eight possible settings for the two 3-bit groups are arranged as an 8x8 matrix, the output frequencies appear as the 64 entries in Table 2. As mentioned above, seven frequencies are duplicated, so there are only 57 distinct frequencies. In Fig. 2, they are generated by programming the two counters using DIP switch S2. Thus, the entries for row two are shift- ed one column left from those of row one. For example, to generate 100 kHz, you can use settings of either P,P 2 P 3 P 4 P 5 P 6 = 000001 or 001000. As a more general example, P,P 2 P 3 P 4 P 5 P 6 =100010 causes divi- sion by 4x10^ = 4x100 = 400. Since the crystal frequency is 1 MHz, the output frequency is/ OUT =l MHz/400 = 2.5 kHz. Figure 3 shows an alternative man- ual approach using rotary switches S3 and S4 to control diode matrix DI-D18. if you find using a DIP switch awkward. In this case, S3 se- lects the decade frequencies from 0.1 Hz-I MHz, while S4 selects the eight output divisions from Vi-Vn, deter- mining the final output frequency, as shown in Table 2. Also, you can see that the +4.5 volts DC from battery Bl in Fig. 2 has been replaced in Fig. 3 with +5 volts DC, which is also acceptable. If you're only interested in 0.1 Hz-1 MHz using the second counter, then exclude S3 and D1-D9, leaving pins 2-4 {P 3 P 9 P,) open. Likewise, if you're only interested in division by the integer factors provided by the first counter (1, 2, 3, 4, 5, 6, 10, and 12), you can similarly exclude S4 and D10-D18, leaving pins 5-7 (P 6 P 5 P 4 ) open. The parts placement diagrams 48 TABLE 1— PXO-1000 FREQUENCY DIVIDER PROGRAMMING CODES RESET EXC TEST ?rc c , 9L ?( p. p 2 p 3 DIVIDER RATIO P 4 Ps p 6 DIVIDER RATIO 1/1 1/1 1 1/10 1 1/10 1 1/2 1 1/10 2 1 1 1/3(*) 1 1 1/103 1 1/4 1 1/10* 1 1 1/5(**} 1 1 1/105 1 1 1/6 1 1 1/10 6 1 1 1 1/12 1 1 1 1/10 7 Notes: (a) 33.3% duty cycle (*); (b) 40% duty cycle {**); (c) All others 50% duty cycle. for the PC boards and the part layout for the DIP- and rotary- switch ver- sions of the PXO-1000 are shown in Figs. 4 and 5, respectively. The PC foil patterns for both versions are shown in PC Service. Note that pins 10-15, the special function pins of the PXO-1000, are unused. Should you wish to use them, several have already been discussed. Of the remainder, pin 10 (test), when set high, multiplies the output fre- quency by 1000, except when the product of the programmed divider ratios for each counter is under 0.001 . Pin 14 (reset) resets both counters FIG. 4— PARTS-PLACEMENT DIAGRAM for the dip-switch version of the PXO-1000 circuit. when set low, and sets pin 9 (out) low. Also, all inputs except pins 12 (exc) and 14 (reset) have internal pull-down resistors, whereas pin 14 (reset) has an internal pull-up resistor. Construction Both the DIP- and rotary-switch versions in Figs. 2 and 3 can be in- stalled in small plastic or metal en- closures with three AA or AAA s< TA 1 BLE 2— PXC 2 M000 DIVII 3 )ER FREQL 4 IENCIES 5 6 7 8 s 3 s z P 4 1 1 1 1 P 5 1 1 1 1 Pi P 2 P 6 P 3 1 1 1 1 1 1 MHz 100 kHz 10 kHz 1 kHz 100 Hz 10 Hz 1 Hz 0.1 Hz 2 1 100 kHz 10 kHz 1 kHz 100 Hz 10 Hz 1 Hz 0.1 Hz 0.01 Hz 3 1 500 kHz 50 kHz 5 kHz 500 Hz 50 Hz 5 Hz 0.5 Hz 0.05 Hz 4 1 1 333.3 kHz(*> 33.3 kHz 3.33 kHz 333.3 Hz 33.3 Hz 3.33 Hz 0.33 Hz 0.033 Hz 5 1 250 kHz 25 kHz 2.5 kHz 250 Hz 25 Hz 2.5 Hz 0.25 Hz 0.025 Hz 6 1 1 200 kHz(**) 20 kHz 2 kHz 200 Hz 20 Hz 2 Hz 0.2 Hz 0.02 Hz 7 1 1 166.67 kHz 16.67 kHz 1 .67 kHz 166.67 Hz 16.67 Hz 1.67 Hz 0.167 Hz 0.0167 Hz 8 Notes: 1 (a) 33 (b)40 (c) Al 1 .3% d % dut other 1 uty cy y cycl s 50% 83.3 kHz cle (*); 3 (**); duty cycle. 8.3 kHz 833.3 Hz 83.3 Hz 8.3 Hz 0.83 Hz 0.083 Hz 0.0083 Hz c z m to to o 49 FIG. 5— PARTS-PLACEMENT DIAGRAM FOR THE ROTARY-SWITCH version of the PXO-1000 circuit. \U RESET IC1 PXO-1000 'nil OUT -INPUT GATE IIC1-T1 GATE IC2 /< 7400 jh — Ln_rLn_rLr i IC2-3 1MHz OUTPUT PULSE TRAIN JTJTJ~Ln-iMHi FIG. 6— AN APPLICATION OF PRECISION LOGIC GATE TIMING using the PXO-1000. If you program 10 kHz, NAND-gate IC2 is enabled on each positive half of the output square wave, for a pulse width of 50 pj.s. That lets 50 1-MHz square wave pulses from pin 11 (/out) o' ™e PXO-1000 pass though IC2 until pin 9 (out) goes low on each bottom half of the square wave. In that case, IC2 is disabled, giving a precise gate time. When both inputs go high, the output goes low, inverting the 1-MHz square wave. PARTS UST Semiconductors: D1-D1&— 1N4148, switching diodes 1C1 — PXO-1000, programmable crystal oscillator IC2— 7400 quad TTL nand gate (see text about precision timing applica- tion) Other components: B1 — 4.5-volt DC supply using three 1,5-volt DC AA or AAA alkaline cells (optional; a 5-vott DC supply could be used instead) J1 — RCA phono jack (for both the DIP- and rotary-switch versions) S1— -miniature SPST toggle switch (for either the DIP- or rotary- switch versions) S2— DIP switch with 6 SPST switch- es (for the DIP-switch version) S3, S4— SP12T rotary switch (for the rotary-switch version) Miscellaneous: PC board (see PC Service), 3-cell AA or AAA battery holder, suitable plastic box with alu- minum cover (for either the DIP- or rotary-switch versions), wire, sol- der, knobs (for the rotary-switch version), Vi-inch spacers, and hardware. Note: The Statek PXO-1000 is available from Ryno Electron ics, 1637 North Brian Street, Orange, CA 92667, (714) 637-0200, for $12.00 postpaid. An etched and drilled PC board (for the rotary- switch version only) is available from R&R Associates, 3106 Glendon Avenue, Los Angeles, CA 90034, for $3.00 postpaid. For both items, California resi- dents include appropriate sales tax. 03 O o d H O LU _l LJ 6 < alkaline cells. Maximum supply volt- age for the PXO-1000 is +6 volts DC. Since the PXO-1000 draws 1 mil- liamp, three AA cells give hundreds of hours of use. Mount the PXO- 1000 in a low-pro- file 16-pin DIP socket. Mount both rotary switches and an ON/OFF switch for Bl on the front panel. The PXO-1000 internal crystal os- cillator is available on pin 9 (out). It's buffered for TTL or CMOS loads, but you should never connect it to a load drawing over I milliamp. If you don't know how much current will be used, put a 5K Vi-watt resistor from pin 9 (out) to Jl to limit current. Note that Jl only appears in Fig. 2, not Fig. 3, but you'll need it in both versions. "fou may also want a large coupling capacitor from pin 9 (out) to the cen- ter post of Jl, although it'll distort even a low- frequency square- wave output. Use a 3-cell A A or AAA bat- tery holder for Bl, a suitable case, and l /4-inch spacers to keep the board from shorting. Applications What can you do with all these fre- quencies? As mentioned earlier, the range of 0.01 Hz- J MHz in decade steps can be used for a variety of cal- ibrations, while some other applica- tions may not be as apparent. For example, 5 Hz can drive a clock motor, 1 , 25 , and 50 Hz are a useful general-purpose time base, 100 Hz-10 kHz are useful for audio, 25 kHz is in the ultrasonic transducer range, 500 kHz-1 MHz is useful for digital applications. By using period instead of frequen- cy, or T = 1/f, you can perform preci- sion logic timing, as shown in Fig. 6. If you program 10 kHz, NAND-gate IC2 is enabled on each positive half of the output square wave, for a pulse width of 50 p,s. That lets 50 I -MHz square wave pulses from pin 1 1 (f OUT ) of the PXO-1000 to pass though IC2 until pin 9 (out) goes low on each bottom half of the square wave. In that case, IC2 is disabled, letting you pick a precise gate time. If both inputs go high, the output goes low, inverting the 1-MHz square wave. R-E 50 Everything you need to know about the varieties of surround sound, in the theater and at home. ALL ABOUT SURROUND SOUND JOSEF BERNARD "MOVIES ARE BETTER THAN EVER!" screamed the advertising banners in the middle of the 1950's as theatrical audiences dwindled and stay-at-home TV audiences grew. Hollywood tried everything it could think of to main- tain its hold on the vanishing moviegoer: Cinerama, 3-D, Cin- emaScope, VistaVision, Todd-AO, six-track stereo sound, eight-track stereo sound, Smell-O- Vision (no kidding!), and other schemes now better forgotten. One or two of the concepts and techniques that were in- troduced during that period proved to have some worth and they or their descendants are with us still today. The stereo and surround sound we enjoy from our audio and video equip- ment at home are among the benefits that have been derived, at least in part, from the motion picture industry's frantic '50's efforts. Early attempts Of the early efforts to provide real- istic sound in a theatrical environ- ment, perhaps the best remembered (if it is remembered at all) is Walt Disney Studios' Fantasound, a four- teen-track process that was used for Leopold Stokowski's orchestral ac- companiment to 1940's animated Fantasia. Each member of an array of microphones spread out before the or- chestra picked up the sound emanat- ing from its region. The signal from each mike was recorded on its own soundtrack and during playback was reproduced by a speaker positioned behind the screen in a location corre- sponding to that of the mike during recording. The effect was a realistic spread of the orchestra before the the- atrical audience. With the cinematic wide-screen spectaculars of the '50's came multi- track stereophonic- — actually, sur- round — sound. Mike Todd's wide- screen extravaganza Around the World in 80 Days included such effects as a train (with the theatergoer as passenger) crossing a rickety old bridge; you could hear the steam en- gine in front of you and the clickety- clack of the wheels on the rails being reflected from the girders of the bridge on either side of you as you passed them. Wow! At home, in the late '50*s and early '60's, record players (there weren't many audiophiles with turntables back then) and a very few tape record- ers went stereophonic . By that time it had been realized that a more-or-less convincing soundstage could be rec- reated in front of the listener from just two channels of sound, one carrying left -ear information and the other car- rying that for the right ear. The term "binaural" was sometimes used in place of "stereophonic," but its use soon became reserved for a specific method for stereophonic recording and listening, one with which most people did not wish to become in- volved because of its inconvenience. The binaural technique, which en- joys a very limited — but extremely spirited — popularity today requires special recording techniques, and c z CO CO o 51 (0 g z o IT i LU _l LU < DC binaural recordings must properly be auditioned through earphones. Only two microphones are used. The idea is to reproduce as closely as possible the sound of a performance (or environ- ment) as it is perceived by the ear. To this end, binaural recording tech- niques have used models of the human head (and ear) fitted with mi- crophones (see Fig. 1), and even mi- crophone mounts that were affixed to real, live, human heads. When pre- pared properly and with care, a bin- aural recording can provide the listener with a surround sound experi- ence that includes not only front, sides and rear, but up and down as well. Earphones must be used to de- liver the sound directly to the ear and preserve the phase relationships of the signal as recorded. In the late 1970's, home dis- cophiles could have their choice of two systems for four-channel record- ings (SQ and QS), with two speakers in front and two behind (see Fig. 2). Both used matrixing systems to en- code the quadraphonic {sometimes spelled "quadri phonic") signals on black vinyl records, and required new designs in cartridges and styli to re- trieve the signals from the record grooves. The two systems offered to the public were incompatible and that, together with a surfeit of gim- micky recordings similar to the "Ping-Pong Stereo" ones that for- tunately disappeared quickly from the two-channel scene, caused the quad- raphonic movement to founder and sink with only a few diehard survivors left today. There weren't many people who wanted to listen to the Tijuana Brass while sitting right smack in the middle of the band; maybe just a few frustrated hom players. Extracting ambience After the failure of quadraphony, the place and purpose of surround sound were reexamined and it was decided that, for the most part, audio channels in addition to the front two conventionally used for stereo should be subordinate to them. It would be OK to have more than two channels, but the main audio information should come from in front of the lis- tener and the secondary channels used more to provide a feeling of am- bience — to recreate the original (or a simulated) recording environment. In the 1970's, a simple way to re- cover ambience information from FIG. 1— IN TRUE BINAURAL RECORDING, a mechanical replica of the human head and ears ensures the proper capture of phase relationships. This is the MKE 2002 binaural dummy-head stereo-microphone setup from Sennheiser. To hear the special stereo effects, the recording must be listened to with high-quality headphones. _ sntai^csijCft/otcootn % & HEAR SPEAKERS ULAMtC A " A FIG.2— THE QS-J004-CH ANN EL Converter/Synthesizer/ Amplifier from Sansui. This is an example of a quadraphonic amplifier in the QS format. conventional stereo recordings was proposed. That ambience informa- tion — -which consists largely of sounds from outside the soundstage located between the stereo micro- phones (assuming, for the sake of simplicity, that just two are used) — ■ may simply be sound reflected from the walls and ceiling of a concert hall, or it may come from sources such as instruments positioned intentionally outside the bounds of the soundstage, as illustrated in Fig. 3. One of the ways that the ear pinpoints sound sources is by determining phase rela- tionships. If, for example, the sound waves heard from a pair of speakers by the left and right ears are in phase , the sound source is perceived as being between the two speakers. If the 52 FIG. 3— AMBIENCE INFORMATION recorded as a left-minus-right difference signal can be used to expand a soundstage and even to localize sounds coming from beyond the bounds set by the locations of the microphones or speakers. V A-B __J FIG. 4— BY INVERTING THE POLARITY of one of a pair of signals and then summing the two, you can obtain the difference between them. rj E^ [J I SPEAKER A SPEAKER B FIG. 5— THE MATRIX SURROUND CIRCUIT used in receivers such as Teac's AG-75 extracts ambience information from a pair of stereo signals by finding the difference between them. waves are out of phase, the sound seems to come from "beyond" the speakers, and some recordings inten- tionally include out-of-phase material to provide special auditory effects. Out-of-phase information can be described mathematically as the dif- ference between the left and right sig- nals, or L — R. The relationship between an "L" waveform and an "R" one is depicted in Fig. 4, By inverting the phase of the right sig- nal — thereby creating a " — R" one- — and adding that signal to the normal "L" one, the "L — R" difference sig- nal representing ambience informa- tion is obtained. By connecting a third (ambience channel) speaker be- tween the "hot" speaker terminals of a stereo amplifier, an L - R signal is obtained and reproduced through that speaker. If you place the speaker be- hind you, and adjust its volume so that it's unobtrusive, recordings that con- tain a goodly amount of natural am- bience material will take on a spaciousness that can make you feel a lot more like you're listening to a per- formance in a real performance en- vironment rather than your living room. Matrix surround sound A number of today's stereo re- ceivers include a feature called "ma- trix surround sound," or just "matrix surround," the "sound" having dis- appeared somewhere. The term "ma- trix" refers to the way the signals are combined to obtain the "surround" signal. The process is a passive one — there is no special encoding or decod- ing matrixing circuitry used. Figure 5 shows a circuit used in one matrix- surround receiver. When the a speak- ers button is engaged, normal stereo sound is heard from the speakers con- nected to the a terminals; when the b speakers switch is closed, the output of the amplifier is fed to a second set. When both switches are closed, the a speakers reproduce the normal stereo signal; what goes to the bs speakers, however, is now the difference be- tween the left- and right-channel sig- nals . It turns out that matrix surround is nothing more than a "ready-to-use" version of the "third channel" am- bience system described above. Place the b speakers behind you, and you have an ambience synthesizer. You also get a free surprise, which is a subject to which we'll return. Some sound equipment also boasts a "Hall Surround" mode. While there is definitely a Ray Dolby involved in Dolby Surround (see below), there is no Mr. Hall of the same prominence involved in audio processing. The term "hall" refers simply to a large room (as a concert hall); presumably time delay or reverb effects are added 53 to the rear channel sound to give a feeling of spaciousness. Sonic holography In photography, holography is a process that yields three-dimensional images from a single piece of film without the need for special viewing apparatus (as opposed to the older method that requires a separate pic- ture for each eye — the system used, for example, by View Master reels). Sonic holography produces a sonic image having depth, and a degree of surround effect, using just a pair of stereo speakers. Sonic Holography, which is a tech- nique patented by Carver Corpora- tion, works on the principle that when we listen to a pair of stereo speakers the phase relationships contained in the recorded or broadcast material are muddied by right-channel sound "leaking" to the left ear, and left- channel sound similarly showing up at the right. What the process does (see Fig. 6) is to inject some degree of out-of-phase right-channel informa- tion into the left-channel signal (and vice-versa). If that is done with the right time delay, the out-of-phase right-channel signal mixed with the left-channel one will arrive at the ear at the same time as the right-speaker "leakage" does, and the in-phase and out-of-phase signals will cancel one another. What's left will be pure left- and right-channel sound as engi- neered, providing a sense of depth and expanse otherwise impossible in a two-speaker system. Material that contains a lot of natu- ral or synthetic L - R information can be astonishing when heard through a sonic-holography system. The sound- stage appears to extend far beyond the backs of" the speakers — indeed, the speakers almost seem to disappear — and "offstage" sounds often seem to originate from places far beyond the left-right bounds of the conventional stereo soundstage. The original Carver sonic hologra- phy process requires some effort to make it work at its best. Speaker posi- tioning is extremely critical to the effect, and speaker-to- listener dis- tances must be measured extremely carefully, and the corresponding left and right ones matched to within an inch or so of one another. The benefits of sonic holography also are restricted to only one or two listeners at a time. The effect is heard only from a highly sensitive "sweet spot," and moving just a foot or so out of it destroys the illusion. In some of its equipment Carver now offers what it calls a Precognition Matrix, which is intended to broaden the sonic-holograph soundstage cre- ated from motion picture sound- tracks. The precognition circuitry works by detecting the (normally in- audible to the ear) rise in noise-floor level when additional tracks are mixed into the stereo master. By changing the mix of left and minus- right-channel information, the appar- ent soundstage can be widened dy- namically to follow that of the material being reproduced, allowing more listeners to benefit from the sonic holography process. Because the change in noise-floor level occurs several milliseconds before the actual onset of the new audio materia! , the processor can respond without miss- ing a note of music or other material. For those who want everything (or nearly everything). Carver also pro- duces an AM/FM stereo receiver that incorporates both Sonic Holography and Dolby Pro Logic Surround, which will be discussed below. Other two-speaker systems There are several other single-end- ed systems that attempt to recreate a measure of ambience from just the information contained in the two channels of an ordinary stereo signal. The system that seems to have at- tracted the most attention of late is the SRS system developed by Hughes Aircraft and licensed by Sony for use in some of its television receivers. Basically, the process extracts the L— R ambience information and pro- cesses it through frequency, timing, and phase adjustments to simulate the way the recorded information would have been perceived by the human ear. The effect is an artificial analog of the binaural process described earlier, using loudspeakers instead of ear- phones. The Hughes SRS system is described in detail in the September 1989 issue of Radio-Electronics. Most "simple" surround systems, though, are just variations — and minor ones, at that — of the L - R ma- trix process. Sometimes the term "digital" gets thrown in, but the dig- ital portion of these processes often has to do just with creating the out-of- phase L — R signal, and maybe adding some time delay for increased "spaciousness." in o z o £ H O Hi _i Lil 6 □ < L 9 OR i>~i DELAY LINE INVERTER r>oa •© V-L FIG. 6 — CARVER'S SONIC HOLOGRAPHY process compensates for signal "muddying" that occurs during ordinary stereo reproduction by using signal cancellation techniques. Dolby Stereo Although it has been in use since 1975, Dolby Stereo, one of a number of audio processes to come from the laboratories headed by Ray Dolby, first came to national cinematic atten- tion with George Lucas' Star Wars in 1977, Anyone who's seen the full- blown version of that film will never forget the opening scene, where the massive battle cruiser looms onto the screen, appearing — to both eye and ear — to come from behind and above the theatergoer. What an introduction to Dolby Stereo! Movies with stereo soundtracks — most of them musicals — were not rarities prior to that, but the Dolby process added one or two things to mere lateral directionality. The first 54 was Dolby A noise reduction, which (as you'Ii know if you ever heard the Star Wars soundtrack cranked way up, as it was in most theaters) gave op- tical-soundtrack sound a much great- er dynamic range than it had enjoyed before. The second, and perhaps more significant from an entertain- ment point of view, benefit of Dolby Stereo was that it added, in a rather elegant and easy-to- achieve manner. True stereo. That is, the sound field, which had previously been zero-di- mensional (monophonic) or one-di- mensional (conventional stereo), now took on another dimension and gain- ed front-to-back depth as well. The word "stereo" derives from the Greek word meaning "solid," and with Dol- by Stereo, movie sound fields took on solidity. Although there is a six-track ver- sion of Dolby Stereo, in which each soundtrack carries discrete (non-ma- trixed) information for a single output channel, the process used for most theatrical releases requires only two tracks. With the Dolby process, those two tracks can provide up to four channels of sound. Figure 7 shows how Dolby Stereo works. The left and right channels contain the usual left- and right-channel information; a movie theater without a Dolby Stereo decoder (or a home videotape viewer using just a stereo VCR) would per- ceive a nearly-normal left- and right- channel soundtrack. (With only monophonic facilities, the two chan- nels would be mixed to produce a single composite output.) With a Dol- by decoder, though, two more chan- nels of sound become available. The first is a front-center channel. This is a mixture of the left- and right-channel signals — a composite mono signal in effect — that fills in the audio "hole" that might be perceived by a moviegoer sitting close to the center of a wide screen. The really interesting part of a Dol- by Stereo soundtrack, though, is the fourth, surround, channel. It is en- coded on the stereo tracks as "L-R." "Wait a minute!" you say. "That's the same information that you can extract from ordinary stereo for a matrix-surround rear channel system. What's the big deal?" The big deal, it turns out, is in what information is encoded in that difference signal. Ma- trix surround uses natural, or at least natural-sounding, ambience informa- tion. What the Dolby process uses is DOLBISH SURROUND Once you know how Dolby Sur- round information is encoded on a stereo soundtrack — namely in the form of an L - R difference signal — it is easy to extract it. While surround decoders bearing the Dolby "double- D" logo contain extra circuitry to pro- vide such things as bandbass filter- ing and Dolby-B noise-reduction decoding, you can have surround sound — using the Dolby-encoded in- formation — from your stereo VCR or other stereo source such as an over- the-air or cable broadcasts of films containing surround-encoded mate- rial for about $25 — including the cost of the speaker! The easiest method to reproduce the L- R "surround" signal, whether it contains natural ambience informa- tion or Dolby Surround programming, is simply to subtract the right-channel signal from the left-channel one at the speaker terminals. You can do that by connecting a speaker, which will become your rear surround speaker, between the two positive (" + ") speaker terminals as shown in the figure. Signals common to both channels will not be reproduced (or will be reproduced at a reduced level), but the differences between the two — the L-R information — will. Since that is exactly what the Dolby process uses, the third speaker re- producing that signal will become the surround device. The process is not perfect (other- wise there would be no market for the more complex and expensive de- much more controlled. However, for the curious, a method for obtaining a surround effect from Dolby-encoded material without the use of a decoder is described in the box above. It's primitive, but effective. vices being sold as Doiby Surround decoders), but It will give you pretty amazing results from good material at a rock-bottom price. If you connect the surround speak- er directly to your amplifier's usual speaker-output terminals, you should use an L-pad in the line to let you control the level, and thereby the bal- ance, of the surround effect sound. You don't want the effect to be over- whelming; most of the time there should be so little of it that you're not aware it's there, although if you were to eliminate it suddenly you would be struck by its absence as the sound- field collapsed. Be careful when adding a third speaker to your system in that way. Putting the impedance of the extra speaker across that of the other two will change the impedance of the en- tire system, and may reduce it below the minimum impedance recom- mended for your amplifier. At very low output levels that may not matter, but at higher ones it can put an unaccep- table strain on the amp. A slightly more complex way, but one reeking less of brute-force, to ob- tain surround sound using that meth- od would be to mix the line-level signals from a pair of your amplifier's tape output jacks in the same way you would combine the speaker-out- put ones — by using the two inner conductors of the TAPE OUT cables — and feed that signal to a separate small mono amp driving the surround speaker. R-E Cinematic sound is an extremely artificial medium — even such a sim- ple effect as the sound of an actor's £ footsteps as he walks from one side of jz a scene to the other is much more ^ easily created on an engineering con- g 55 I INPU7S< (V. o- R O— INPUT BALANCE CONTROL LEVEL CONTROL L+R ^ OPTIONAL CENTER SIGNAL OELAYSET Q ANTI- ALIAS FILTER JL AUDIO DELAY R, MASTER LEVEL CONTROL -O RIGHT -o CENTER 3 SURROUND OUTPUTS 7kHz LOW-PASS FILTER FIG. 7— THEATRICAL DOLBY STEREO encodes four channels of sound on two sound- tracks. The Dolby decoder derives a center channel by summing the left and right channels, and surround information by subtracting the right from the left. MODIFIED -* B-TYPE NR DECODER m g HI O 5 < sole with a couple of pan pots than on the soundstage during filming. Most of a film's soundtrack is realized in post-production — and that tightly controlled environment makes it rela- tively easy to put on the surround track exactly what is wanted, without having to rely on natural material. If you listen carefully to a plain stereo playback of a Dolby Stereo soundtrack, you can frequently detect the presence of the surround effects — they appear to come from outside the speakers' soundstage, the way out-of- phase ambience information may. That is clearly evident in a film such as Back to the Future, when the time- travelling DeLorean comes swoosh- ing toward or away from the camera. If all four channels of sound are re- produced, you hear the car moving from front to rear, or vice-versa. In plain- vanilla stereo, though, you can plainly hear the car noises corning from the far-left and far-right- — off- stage, as it were. In creating an L - R surround sig- nal, the Dolby Stereo process does two things. The first is to cut off the rear-channel signal at 7 kHz. That is done for several reasons. The first has to do with eliminating signal leakage and distracting crosstalk from the sur- round channel. Another big reason has to do with economy. There is no need for high fidelity in a surround channel — most of the time the sound there is for "presence" — that is, you are only unconsciously aware of it. The track is meant to be unobtrusive , not to have you constantly aware of its presence. It's only if the surround channel should suddenly fail that you should become consciously aware of its presence (or absence). That limited frequency response is the reason behind those cheap-look- ing, PA-type speakers you may have noted in movie theaters equipped for Dolby Surround. It's not that the the- ater-owner is a cheapskate; simply that there is nothing on the surround track to justify the expense of a belter speaker. As far as low frequencies go — the rumble of the engines of the Empire spaceship, for example — they are carried as ordinary left and right information. Since your ears cannot determine where frequencies below about 120 Hz originate, they can be reproduced from low- frequency driv- ers located anywhere. The visual con- tent of the film will cue you as to where the sound is supposed to be coming from. The second thing that is done to the rear-channel signal is to encode it using a modified form of Dolby B noise reduction. The modification consists of adding only five dB of processing instead of the normal ten dB. The use of Dolby B provides a degree of noise reduction and assists in reducing front-channel signal leak- age, while the low level of processing prevents the encoded surround signal from significantly altering the nature of the left- and right-channel signals heard up front.' In the decoding process, a third element is added to Dolby Stereo: time delay. A delay of between 15 and 30 ms is added to the rear-channel signal to take advantage of a phe- nomenon known as the Haas effect. The Haas effect causes the mind to identify the source of a sound as that from which it is first heard and to ignore the same sound arriving later at the ear. That "first arrival" effect en- sures that front-channel sounds are clearly identified as originating from before the viewer, even if they also come from behind him to some ex- tent. Dolby Stereo decoders also make use of steering logic, discussed below, to add further directionality to the decoded soundtrack. Before leaving the theatrical Dolby process, we should mention one called "THX." THX is a trademark owned by George Lucas' Lucasfilm (the name has its origin in the title of Lucas' first feature-length work, a sci- ence-fiction film called THX-H38). All it refers to is a "guaranteed mini- mum" quality of sound in a particular theater from an ordinary Dolby Stereo soundtrack. THX engineers check and adjust the sound-reproduction equipment in a "THX" theater to meet specific standards of perfor- mance. It's just quality control for movie-sound reproduction. Unless you can get a THX engineer to come out to your living room, THX will do nothing for you at home . Dolby Surround and Pro Logic Dolby Surround is the name given to one of the two home versions of Dolby Stereo. It starts with the same two stereo soundtracks that are on the film (now on longitudinal or Hi-Fi tracks on a videocassette). And, as is done in theatrical installations, the surround channel is dematrixed. Dol- by-B decoded, and time delayed be- fore being amplified and fed to a pair of rear speakers. Only one surround speaker is actually necessary, but two — reproducing the same surround signal — give a "fuller" effect. To de- rive a monophonic center channel, useful in preventing a center "hole" when the left and right speakers are widely separated, some Dolby Sur- round decoders mix the left- and right track information. That is not, strictly speaking, necessary, since center in- formation appears equally on both tracks and can be heard appearing from a "phantom" speaker situated continued on page 58 56 kit report: HEATH'S AD-2550 SURROUND SOUND PROCESSOR if you're looking for a fun way to upgrade your audio/video system to include Dolby Surround, Heath's AD-2550 might be the way to do it. It might also be the perfect way to get yourself back into electronics con- struction il you've been letting your skills lapse. The processor is very easy to build. Although we wouldn't recom- mend it as a first project, anyone with even minimal kit-building expe- rience, or anyone who has ever built a project from plans published in Radio-Electronics should have no trouble. Most of the work involves assem- bling one large PC board. There's plenty of room to work, and the sup- plied instructions and silkscreened boards make things as simple as possible. When the board assembly is complete, the final work involves installing it in the metal cabinet and hooking up the power transformer. Our total assembly time was about six or seven leisurely hours. Alignment takes only a few minutes, and can be accomplished either with or without test equipment. Did it work the first time we turned it on? If you have to ask, you've never build a Heath kit! Surround features When you're finished with the as- sembly work, you're left with a full- featured surround-sound processor. The AD-2550 accepts left- and right- channel inputs and offers a wide as- sortment of outputs. First, because the processor includes a 20-watt au- dio amplifier, direct speaker outputs are available for connection to sur- round speakers. Line-level sur- round-channel outputs are aiso offered. Line- level outputs for left front and right front are provided for connection to a separate ampli- fier, or to a stereo TV/monitor. A center-channel output is provided for installations where front- speaker separa- tion produces a can bring it home to your living room! the amount of time delay be- tween the front and rear speak- ers to give your room a larger feel, even if you must place the sur- round speakers close to your lis- tening position. The null control balances the ieft- and right-channel signals that are EVERYTHING THAT'S NEEDED to pro- processed by the sound that is too ^professional results is included with surr ound circuitry. the kit. .. J It can compen- sate for some poorly-encoded mate- rial. Two volume controls — one for MOST OF THE ASSEMBLY work is done on a large PC board. wide for the screen. It helps to keep the dialogue of on-screen actors sounding as if it's coming from the screen, not off to the side. A line-level subwoofer out- put feeds the low-frequency (under 70 Hz) sounds to a separate ampli- fier for room-rattling effects. Three different surround modes are provided by the Heath pro- cessor. First, of course, is true Dolby Surround. "Music surround" adds synthetic surround effects to stereo audio recordings to give them more depth. A "mono enhance" mode synthesizess stereo-with-surround effects. Front-panel controls include a power switch, three pushbuttons for choosing the appropriate surround mode, and four rotary potentiome- ters. First is the delay control to set the surround output and the other for all outputs— let you perfectly adjust the balance of the front and rear speakers. Our tests showed that the decod- ing circuitry performed flawlessly upon completion. But the real test didn't come until we gave it a trial run with some real test material, includ- ing Indiana Jones and the Last Crusade. Surround sound can make a dramatic difference. The soundstage becomes instantly larger, and, if we're allowed a little exaggeration, even the picture seems bigger! Movies that are encoded with Dol- by surround can, of course, be de- (Continued on page 88) t— c z 57 L O— • R o- T T BANDPASS FILTERS LEFT/RIGHT DOMINANCE SENSE /\ POLARITY SPUTTER POLARITY SPLITTER FRONT/REAR DOMINANCE SENSE FIG. 8— THE ADAPTIVE MATRIX used in the Dolby Pro Logic Surround process can provide up to 30 dB of separation between opposite or adjacent channels. That affords an extremely high degree of directionality. BxVCA eg U z o o LU _J Q] 6 Q s between the two front ones. A few Dolby Surround processors can also output a front-and-back mix to side speakers . Finally, most processors on the market also feature a subwoofer output. That has nothing to do with the Dolby process; it's more a con- venience than anything else. Dolby Pro Logic Surround is the ultimate in Dolby Surround process- ing. While the original Dolby Sur- round process is primarily a passive one {all the equipment does, essen- tially, is decode the matrixed informa- tion), Pro Logic decoders contain active circuits that provide a surround effect as good as — if not better than — that in the best movie theater. The active addition to a Dolby Pro Logic decoder is known as steering logic. The purpose of the steering logic circuitry in a Dolby Pro Logic de- coder is to sense the direction of soundtrack dominance — that is, to determine from what direction the loudest sound on the track seems to originate — and to generate control signals that increase gain in the appro- priate (left, right, center, surround) combination of channels to give a di- rectional vector. Figure 8 illustrates the workings of the adaptive matrix within a Pro Logic decoder. By com- paring the left and right and center and surround signal pairs, and taking the logarithms of their values (log- arithms are used, in part, because human senses work in a logarithmic rather than linear fashion), a pair of bipolar control signals is generated, which are used to adjust the gain of eight voltage-controlled amplifiers (four for each input channel). The out- puts of those VGA's, together with the original left- and right-channel signals, provide a total of ten control signals. When those signals are ap- plied to the four output channels, a total of forty summed directional components are available. Separation between any pair of channels — adja- cent or opposite — is 30 dB , compared to Dolby Surround's 3 dB of adjacent separation, and 40 dB of opposite separation. Pro Logic decoders are two- speed devices. When only one sound source is dominant, they run in their "slow" mode. But when there are two distinct sound sources (by definition, only one can be "dominant" at a time), the Pro Logic circuitry goes into a "fast," time-division multiplexing mode where it gives its attention first to one source, and then to the other. It switches back and forth between the two so quickly that its efforts are un- noticed by the listener. Dolby Pro Logic decoders include as a matter of course center-channel and subwoofer outputs . As is the case with the surround channel, the center- channel amplifier and speaker need not have the frequency response of the equipment used for the left and right channels. High- and low frequencies will be reproduced by those systems and by the subwoofer, if one is used. With a good-quality hi-fi-soundtrack videotape, and with even a modest array of home sound equipment, you can experience a quality of cinematic sound at home that you would be hard-pressed to find in any theatrical environment. R-E GENERIC POWER SUPPLY continued from page 46 ble. If the water dries smoothly, from the edges inward, or forms fine bub- bles, you're probably safe. However, if the water boils off immediately, there's trouble. It's not a terribly sci- entific method, but it's free. Check a second time, waiting a full minute after drying for heating recovery. The 78XX/78MXX versions are fixed-positive models. For example, a 7812 is a positive 12-volt model that can provide at least 1 amp of output current — but only when the regulator drop is low enough to avoid overheat- ing. The suffix "T" specifies a TO-220 case, but catalogs often omit this and specify the case type elsewhere. The 79XX/79MXX ver- sions are fixed-negative models. The LM317/LM317M models are adjusta- ble-positive, and the LM337/ LM337M are adjustable-negative. They're ail very reliable, and can take considerable abuse. R-E 58 The days of LED indicators and segmented displays are numbered. Now you can add an alpha-numeric LCD to your home project easily and inexpensively STEVEN AVRITCH HAVE YOU EVER AVOIDED A PROJECT BE- cause it required a display that could handle numbers, letters, and sym- bols? Have you ever given up on a project because the display had to be at least 10, 20, maybe even 40 charac- ters long? "feu can solve all of those problems by using a simple and inexpensive alpha-numeric LCD module which contains a controller chip that does most of the work for you! This article will show you how to use LCD's with a simple microcontroller- or micro- processor-based design. Note that most small LCD modules use the Hitachi HD44780 LCD controller chip (see block diagram in Fig. I). This article will therefore be limited to a discussion of LCD modules that use, or are compatible with, the HD447S0 controller format. Com- mon LCD modules include those manufactured by Optrex, Epson, Hitachi, Amperex, and Densitron. Multi-character readouts are usu- ally constructed using individually wired, multiplexed display segments. The host microprocessor sequentially flashes the desired character on each digit of the display, one at a time. The microprocessor is fast enough so that the naked eye sees the display as it should appear. That method of multi- plexing the digits of a display is often used because it reduces the amount of external hardware required compared to non- multiplexed systems. How- ever, multiplexing requires the micro- processor to continually update the display, and the amount of external wiring must be increased as addi- tional digits are added (see Fig. 2). For example, a 10-digit numeric display requires approximately 100 wires and over 20 components. (A 10- digit alpha-numeric display requires even more wires.) The equivalent dis- play (including alpha-numerics) im- plemented with an LCD module would require only 10 wires and 2 components: the LCD module and a potentiometer for contrast control. Using an LCD module, a designer can add a display containing up to 80 characters with as little as 10 wires, 7 of which connect the display module to the host microcontroller/processor, plus I power, 1 ground, and 1 LCD drive wire for contrast control. That's all! The software interface between the host and the display module is just as simple as the wiring. The display modules automatically handle all re- fresh and multiplexing functions. The host needs only to write the data to be displayed and a few control codes (such as display on, display off, scroll left, scroll right, etc.) to the module; the on-board LCD controller chip does the rest. LCD modules have not been used heavily in the past because of their high costs. However, the cost of the modules has since dropped consider- ably, and they are now commonly found in many of the popular elec- tronics supply houses. For example, a 32-character display (2 lines, 16 characters per line, 16 X 2) is available from Digi-Key for approximately $23. Similar displays can be obtained through surplus houses for approxi- mately $8-$ 10. Most of the small, inexpensive LCD modules contain a Hitachi HD44780 LCD Controller chip. That means that most of LCD modules fol- low the same standard format, have the same 14-pin interface, and are therefore compatible and inter- changeable. The HD44780 is capable of controlling any size display up to 2 lines long and 40 characters wide with the same hardware interface. Com- monly available display sizes include 16x1, 16x2, 20x2, 24x2, and 40x2 formats. That means that you O 59 LCD DISPLAY MODULE TO HOST PROCESSOR/ O LI O l l LI I I TO OTHER SEGMENTS TO OTHER SEGMENTS M g^^q^i TO OTHER SEGMENTS FIG. 2— MULTIPLEXING REQUIRES the microprocessor to continually update the display, and the amount of external wiring must be increased as additional digits are added. can change the size of your display by simply plugging in a larger module. No other hardware modifications are required; only the software drivers specific to the application would need to change. The LCD modules recognize stan- dard ASCII code for letters (upper and lower case) and numbers in addi- tion to a variety of symbols including ?, !, $AK, %, and \ just to name a few. In all, the LCD module supports 192 alpha-numeric characters and 32 special symbols. The modules also allow you to customize up to 8 user- defined characters of your own. On one home project the author customized three characters that, when displayed together, formed an airplane as can be seen in the photo. The LCD modules are dot-matrix type displays with each character being formed from a 5-dot-wide by 7- dot-high block (5x7 font) or a 5-dot- wide by 10-dot-high block (5x10 font). The font is selected by issuing a control command as discussed later in this article. There is also a cursor line under each character. The 5 X 10 font is bet- ter suited for certain lower-case letters such as g, y, and p (i.e. letters with descenders that go below the line that they're written on). Figure 3 shows examples of letters formed using the 5x7 and 5 x 10 dot-matrix formats for comparison. It should be noted that the 5 x 10 matrix font limits the display to one line regardless of whether the LCD module is a one-line or two-line display. FIG. 3— HERE ARE SOME EXAMPLES of letters formed using the 5x7 and 5 >;10 dot-matrix formats. blinks. • Scroll left/right — scrolls the data on the display. • Return home — returns the cursor to the home position (address 0) and returns the display to the original po- sition (if it had been previously scrolled) Software interface The software interface between the LCD module and a processor or mi- crocontroller is relatively simple. There are two basic types of software operations: control operations (i.e. display on/off, cursor blink/noblink, etc.) and data operations. The control operations set up the features of the display, while the data operations write the actual data to be displayed to the LCD module. The LCD module's on-board HD44780 controller chip contains 80 bytes of display RAM and is capable of supporting up to a 40 x 2 display (each byte of display RAM corre- sponds to a digit of the display). Smaller LCD modules simply do not 60 display the full 80 bytes of RAM. The display RAM is organized in the fol- lowing format: LINE 1: Character position: 12345678 9. ..40 RAM address 12 3 4 5 6 7 8...27{hex) LINE 2: Character position: 12345678 9... 40 RAM address 40 41 42 43 44 45 46 47 48...67(hex) Smaller modules simply do not dis- play the upper character positions as- sociated with the upper addresses. For example, a 16x2 display uses ad- dresses 00-4)F (hex) for line 1 and 40-^F (hex) for line 2. The HD44780 also contains 64 bytes of character-generator RAM. That is used to store the character patterns of the 8 user-defined charac- ters (8 bytes per character). Once a user-defined character is set up in character- generator RAM, it may be accessed just as any other regular character. NOTE: in the 5 X 10 matrix mode, only four user-defined charac- ters are supported, with each character requiring II bytes of character-generator RAM. Software drivers The host must contain two basic software drivers to support the LCD modules , the Control Write and Data Write drivers. The minimum func- tions that the software drivers must perform are: Control Write: • Sets up DB0-DB7 with the desir- ed control code • Sets the RJ w line to logic zero • Sets the rs line to logic zero • Strobes the enable line Data Write: • Sets up DB0-DB7 with the desir- ed character • Sets r/w line to logic zero • Sets the rs line to logic one • Strobes the enable line The user may also read data and control signals from the HD44780. Control Read and Data Read drivers are similar to the write drivers except that the ww line is set to a logic one. Refer to Table 1 for a complete listing of the control codes and status flags available with the HD44780 LCD controller chip. Subroutines for the MC 68705 The following subroutines show the DISLET DELAY1 CONTROL INIT LDA JSR LDA JSR LDA JSR LDA JSR LDA JSR RTS STX STA BCLR BSET BSET BCLR BCLR LDX DECX BNE LDX RTS STX STA BCLR BCLR BSET BCLR LDX DECX BNE CMP BHI JSR DECX LDX RTS #$01 CONTROL #$02 CONTROL #$38 CONTROL #306 CONTROL #$0C CONTROL LISTING 1 TEMPX PORTA 1 , PORTB 2 , PORTB 0, PORTB 0, PORTB 2, PORTB #$20 DELAY1 TEMPX SAVE INDEX REGISTER PUT CHARACTER ON BUS SET R/W TO WRITE SET RS TO DATA TURN ON ENABLE TURN OFF ENABLE SET RS TO CONTROL \ DELAY 120 us / ASSUMING 1 US / CLOCK RESTORE INDEX REGISTER RETURN FROM SUBROUTINE LISTING 2 TEMPX PORTA 1 , PORTB 2 , PORTB 0, PORTB 0, PORTB #SFF DELAY2 #$02 DELAY4 ENDCNTL TEMPX SAVE INDEX REGISTER PUT CONTROL CODE ON BUS SET R/W TO WRITE SET RS TO CONTROL TURN ENABLE ON TURN ENABLE OFF \ \ DELAY FOR CONTROL RESTORE INDEX REGISTER RETURN OS INIT NEXT LDA JSR CLR LDX LDA JSR INC LDA CMP BNE LDA JSR LDA JSR RTS #540 CONTROL DATCNT DATCNT PLANE, X DISLET DATCNT DATCNT #24 NEXT #$80 CONTROL #$02 CONTROL LISTING 3 CLEAR DISPLAY RETURN DISPLAY TO HOME POSITION SET UP FOR 2 LINES, B BIT INTERFACE, AND 5X7 MATRIX FORMAT SET UP FOR CURSOR SHIFT WITH DATA WRITE SET UP FOR DISPLAY ON, CURSOR OFF, AND STEADY CURSOR (NO BLINK) RETURN FROM SUBROUTINE LISTING 4 SET UP FOR WRITES TO CG RAM CLEAR BYTE COUNTER LOAD BYTE COUNTER LOAD CG RAM DATA INTO ACCUMULATOR WRITE BYTE TO CG RAM INCREMENT COUNTER FOR NEXT BYTE \ / 24 BYTES WRITTEN ? SET UP FOR WRITES TO DD RAM INITIALIZE DISPLAY TO HOME POSITION RETURN FROM SUBROUTINE software drivers for data and control writes. The examples shown here are written in Motorola 6800-series as- sembler code and are targeted for the MC68705 microcontroller. These short routines can be easily translated into other assembly languages that can be used with other micro- controllers/microprocessors . The Data Write subroutine (Listing 1) displays letters and symbols. The ASCII code of the letter/symbol to be displayed must be loaded into the Ac- cumulator before calling the Data Write subroutine. Before the Control Write subroutine (Listing 2) can be called, the code of the control opera- tion to be performed (from Table 1) must be loaded into the Accumulator. Display initialization £ The fi rst operation that the software o 61 DIGITAL VIDEO STABILIZER ELIMINATES ALL VIDEO COPY PROTECTIONS While watching rental moviw h you will notice an- noying period ic color daikentng, color shift, un- wanted lines, flashing or jagged edges. This is caused by Ihe copy protec- tion jamming signals em- bedded in the video lape k such as Macrovision copy projection. Digital Video Stabilizer flXJI completely eliminates all copy protec- tions and lamming signals and brings you crystal clear pictures. FEATURES: • Easy to use and a snap to Install # State-of-the-art in- tegrated circuit lechnol- • 100% automatic - no need for any troublesome adjust- ments • Compatible lo all types of VCRs and TVs • Thn besl and most excit- ing Video Stabilizer In the market •Light weigh! {8 ounces) and Compact (1x3,5x5^ • Beautiful deluxe gift box • Uses a standard 9 Volt battery which will last 1 - 2y»afa> WARNING : SCO Electronics and RXII dealers do not encourage people to use the Digital Video Stabilizer to duplicate rental movies or copyrighted video tapes. RXII is in- tended to stabi- lize and restore crystal clear picture quality for private home use only. ( Dealers Welcome ) ToOrder: $49.95 » + W for fast ups shipping 1-800-445-9285 0. 516-694-1240 Visa, M/C, COO M-F: 9-6 (battery nol Included) SCO ELECTRONICS INC. Dapt. cuts 581 W. Merrick Ftd. Valley Stream NY nsso Unconditional 30 days Money Back Guarantee CIRCLE 194 ON FREE INFORMATION CARD CABLE TV DESCRAMBLER lUnit 10 + Jerrold S.B ...$74 $55 Jerrold SB w/Trimode $90 $70 Oak N-12 (w/VS) $89 .....$65 Scientific Atlanta.. $109....$75 Pioneer. .......$109....$75 Panasonic converter $98 $79 73 channel converter $79 $59 We Beat Anyone's Price! 30 Days Money Back Quaranry free Catalog Visa, M/C, COD or send money order to; US Cable TV Inc. Dept. kct6 4100 N.Powerline Rd., Suite F-4 Pompano Beach, Fl 33073 1-800-445-9285 Please have make and model number of the equipment used in your area ready. No Florida Sales! It's not the intent of US Cable TV Inc. to defraud any pay TV operator and we will not assist any company or individual in doing so. CIRCLE 195 ON FREE INFORMATION CARD TABLE 1 -CONTROL OPERATIONS Instruction RS RW DB7 DM DB5 DS4 DB3 DB2 D0I DBD Description and execution time Clear 1 Clears Display Returns cursor to home position (1.64 ms) Home 1 X Return cursor to home position Return shifted display to home position (40 |is) Mode 1 CD s Control automatic RAM address INCDEC and whether display shifts on writes (40 |*S) Display ON.'OFF t D c B Controls display ON.OFF Controls cursor ON.OFF Cursor blink ON.OFF (40 us) Cursor or display shift 1 SIC tVL X X Sifts cursor and/or display without changing display RAM (40 jis! Function set t D.L N F X X Set Interface to 4 or 8 bits Sel number of display lines Sets character font (40 ns.i Set CG RAM address 1 Address (CG) Sel address for subsequent writes lo character generator. (CG) RAM. (40 (is) Set DO RAM address __D — 1 - Address r \ 1 1 1 1 1 1 D D 1 2 3 D 4 D D 254 255 (B) WRITE SEQUENCE FIG. 2— THE ECONORAM GETS INTERROGATED by use of 264 sequential timing pulses. Once started, the sequence must get completed In its entirety. See the OS2222 data sheet for additional details. The ZERO BOX uses a deep drawn aluminum shell and looks particularly good with a Metalphoto dialplate. Shallow versions can also be used lace up. These anodize beautifully. The VINYL CLAMSHELL has a brushed aluminum chassis and a cover coated with glued-on decorator vinyl. Tilting end brackets can also be added, as can venlillation holes. The WOODEN END RAIL ploy uses exotic wood caps thai have suitable grooves routed in them. The chassis itsell can be painted aluminum or a polished brass or chrome, FIG. 3— HOMEBREW CASES FROM the "golden age" ot hardware hacking. All of these are easily built, yet can produce outstanding professional results. buy some fake Naugahyde by the yard, and glue it onto plain old alu- minum or steel. The "clamshell" de- sign (Fig. 3, middle) is easy to do. You can simply sand the bottom half to get a satin finish, and glue vinyl c 2 m CD 8 65 onto the upper half to get a profes- sional final result. The wooden rail ploy (Fig. 3, bot- tom) is both easy to hack and looks great. Just get yourself some exotic wood from EDLCO or Constantine (Cocoboio or Wenge are fine choices), mill some slots in it with a hobby motor tool, slide in a bent metal frame, and you are home free. I've found a local blacksmith or sheet-metal shop to be real handy at times, so you'll want to find a good one of these on your own. Better yet, see if you can't find a horse trailer or hitch works. They have the machinery to properly cut and bend the heavier stuff without costing an CASE AND PACKAGING RESOURCES y 2 o a: H O o Q < DC 66 Appliance 1110 Jorie Blvds, CS 9019 Oak Brook, IL 60522 (708) 990-3484 CIRCLE 225 ON FREE INFORMATION CARD Coburn 1650 Corporate Road West Lakewood, NJ 08701 (201) 367-5511 Keystone Electronics Corp 31-07 20th Road Astoria, NY 11105 (718) 956-8900 CIRCLE 235 ON FREE INFORMATION CARD Metalphoto 18531 South Mites Road Cleveiand, OH 44128 (216) 475-0555 CIRCLE 226 ON FREE INFORMATION CARD CIRCLE 236 ON FREE INFORMATION CARD Constantine 2050 Eastchester Road Bronx, NY 10461 (212) 792-1600 CIRCLE 227 ON FREE INFORMATION CARD DonJer Products Co tlene Court Building 8 Belle Mead, NJ 08502 (800) 336-6537 CIRCLE 228 ON FREE INFORMATION CARD EDLCO PO Box 5373 Ashevilte, NO 28813 (704) 255-8765 CIRCLE 229 ON FREE INFORMATION CARD Electronic Component News 1 Chilton Way Radnor, PA 19089 (215) 964-4345 CIRCLE 230 ON FREE INFORMATION CARD Electronic Packaging 1350 East Touhy Avenue Des Plaines, IL 60018 (708) 635-8800 CIRCLE 231 ON FREE INFORMATION CARD Fomeboards 2211 North Elston Chicago, IL 60614 (312) 278-9200 CIRCLE 232 ON FREE INFORMATION CARD Fotof oil 'Miller Dial 4400 North Temple City Blvd El Monte, CA 91734 (818) 444-4555 CIRCLE 233 ON FREE INFORMATION CARD Hammond 1690 Walden Avenue Buffalo, NY 14225 (716) 894-5710 CIRCLE 234 ON FREE INFORMATION CARD Mouser Electronics 11433 Woodside Avenue Santee, CA 92071 (800) 346-6873 CIRCLE 237 ON FREE INFORMATION CARD PacTec Enterprise & Executive Avenues Philadelphia, PA 19153 (215} 365-8400 CIRCLE 238 ON FREE INFORMATION CARD Polycase 4726 Superior Avenue Cleveland, Ohio 44103 (216) 391-0444 CIRCLE 239 ON FREE INFORMATION CARD Red Spot PO Box 418 Evansvtlle, IN 47703 (812) 428-9100 CIRCLE 240 ON FREE INFORMATION CARD Serco 612 Commercial Avenue Covina, CA 91723 (818) 331-0517 CIRCLE 241 ON FREE INFORMATION CARD Vector Electronic Co 12460 Gladstone Avenue Sylmar, CA 91342 (818) 365-9661 CIRCLE 242 ON FREE INFORMATION CARD Vero 1000 Sherman Avenue Hamden, CT 06514 (203) 288-8001 CIRCLE 243 ON FREE INFORMATION CARD Zero Halliburton PO Box 3339 Pacoima, CA 91333 (818) 897-7777 CIRCLE 244 ON FREE INFORMATION CARD arm and a leg. And there's usually enough scrap on the floor under the shear. Four interesting package support outfits are the Fomeboards people which do stock all sorts of beautiful prototyping sheet materials; Coburn who is heavy into unusual finishes such as prismatics, glow-in- the-darks, diffraction gratings, foils, etc; instant dust-on flock materials from Donjer, and the Ultra-Suede from Red Spot, a textured urethane finish having a soft fuzzy suede or smooth leather touch. All the enclosure and packaging people advertise in most of the free electronics trade journals. Electronic Component News seems about the best for cases and such. Two other trade journals with useful fit and finish ideas in them include Electronic Packaging and Appliance. Electronic inclinometers The folks at Wedge Innovations are now retailing intelligent elec- tronic levels that display your choice of degrees, pitch, slope percent, level & plumb, autocalib ration, and even a simulated bubble. The sug- gested list price is under $80. Re- lated electronic protractors are being offered by Lucas Sensing Sys- tems. I just thought we might take a quick look at some of the principles of electronic level sensing. You can easily build your own level sensor for under $4. In general, there are two popular ways of telling which way is up. One quite expensive method is the vertical gyro. That is simply a gyro- scope that is spun up while level and stays that way when the world around it moves. Two surplus sources of vertical gyros include Fair Radio Sales and the folks at C&H Sales. A much simpler method is the inclinometer. As Fig. 4 shows us, an inclinometer can be as simple as a plumb bob and a protractor. Your gravity-sensing plumb bob usually points straight down. As the pro- tractor is rotated, its slope angle can be read. There have been several older at- tempts at getting an electrical out- put of an inclinometer. Obviously, you can simply wipe a potentiome- ter, but stiction, wear, and hysteresis can end up as problems. Other early schemes used mercury, but Bomarc Services Box 113 Casper. WY 82602 (307} 237-3361 CIRCLE 245 ON FREE INFORMATION CARD C & H Sales 2716 East Colorado Blvd Pasadena, CA 91107 (213) 681-4925 CIRCLE 246 ON FREE INFORMATION CARD Dallas Semiconductor 4350 Beltwood Parkway South Dallas, TX 75244 (214) 450-0400 CIRCLE 247 ON FREE INFORMATION CARD Don Diers 4276 North 50th Street Milwaukee, Wl 53216 CIRCLE 248 ON FREE INFORMATION CARD Fair Radio Sales 1016 East Eureka Street Lima, OH 45802 (419) 227-6573 CIRCLE 249 ON FREE INFORMATION CARD Genie 401 North Washington Street Rockville. MD 20850 (800) 638-9636 CIRCLE 250 ON FREE INFORMATION CARD Hamlin 612 East Lake Street Lake Mills, Wl 53551 (414) 648-5244 CIRCLE 251 ON FREE INFORMATION CARD Hewlett-Packard PO Box 10161 Palo Alto, CA 94303 (415) 857-1501 CIRCLE 252 ON FREE INFORMATION CARD Hoechst Cetanese 26 Main Street Chatham, NJ 07928 (800) 235-2637 CIRCLE 253 ON FREE INFORMATION CARD that's a hazardous element that's both poisonous and rather low in impedance. Figure 5 shows you another early attempt at an electronic in- clinometer. This one is known as an electrolytic sensor. You place three probes in a conductive liquid in a sausage-shaped enclosure. As the sensor tilts from level, the deeper probe's resistance drops, while the shallow one will increase, A simple op-amp bridge circuit can convert the differential resistance into an NAMES AND NUMBERS Lazer Products 12741 East Caiey Ave #130 Engfewood, CO 80155 (303) 792-5277 CIRCLE 254 ON FREE INFORMATION CARD Linear Technology 1630 McCarthy Blvd Milpifas, CA 95035 (408) 432-1900 CIRCLE 255 ON FREE INFORMATION CARD Lucas Sensing Systems 21640 North 14th Avenue Phoenix, AZ 85027 (602) 256-7674 CIRCLE 256 ON FREE INFORMATION CARD MicroCAD News PO Box 203550 Austin, TX 78720 (512) 250-1700 CIRCLE 257 ON FREE INFORMATION CARD Motorola 5005 East McDowell Road Pheontx, AZ 85508 (602) 244-6900 CIRCLE 258 ON FREE INFORMATION CARD National Semiconductor 2900 Semiconductor Drive Santa Clara, CA 95052 (408) 721-5000 CIRCLE 259 ON FREE INFORMATION CARD Philips 2001 West Blue Heron Blvd Riviera Beach, FL 33404 (407) 881-3200 CIRCLE 260 ON FREE INFORMATION CARD PMI 1500 Space Park Drive Santa Clara, CA 95052 (408) 727-9222 CIRCLE 261 ON FREE INFORMATION CARD R&D Electronics 1224 Prospect Avenue Cleveland, OH 44115 (800) 642-1123 CIRCLE 262 ON FREE INFORMATION CARD output voltage. One obvious choice for a liquid is bromine, one of those few elements that remain liquid at normal temper- atures. Two older sources of the electrolytic level detectors are Hamlin and Spectmn. These de- vices are both fragile and expensive. Most of the bets these days, though, are on the capacitance in- clinometer shown in Fig. 6. That one is simple, cheap, low power, and clean. Picture an insulated enclosure the Science 1333 H Street NW Washington, DC 20005 (202) 326-6400 CIRCLE 263 ON FREE INFORMATION CARD Sharp Sharp Plaza Mahwah, NJ 07430 (201) 529-8757 CIRCLE 264 ON FREE INFORMATION CARD Spectron 595 Old Willets Path Hauppauge, NY 11788 (516) 582-5671 CIRCLE 265 ON FREE INFORMATION CARD STANO Components PO Box 6274 San Bernardino, CA 92412 (714) 882-5789 CIRCLE 266 ON FREE INFORMATION CARD Synergetics Box 809 Thatcher, AZ 85552 (602) 428-4073 CIRCLE 267 ON FREE INFORMATION CARD Texas Instruments PO Box 1443 Houston, TX 77001 (800) 232-3200 CIRCLE 268 ON FREE INFORMATION CARD Don Thompson 23072 Lake Center Dr #100 El Toro, CA 92630 (714) 855-3838 CIRCLE 269 ON FREE INFORMATION CARD Wedge Innovations 532 Mercury Drive Sunnyvale, CA 94086 (800) 762-7853 CIRCLE 270 ON FREE INFORMATION CARD size and shape of a Magician's fake silver dollar. The rear of the en- closure is a grounded metal plate. The front consists of a pair of but- terfly-shaped capacitor plates. The case gets filled exactly halfway with a magic liquid that is an inert in- sulator, has a high dielectric con- stant, a medium viscosity, is non- wetting, non-corrosive, and has a very high vapor pressure. Propylene ^ is one possible choice. ^ After filling, your case is sealed. ^ When level, each of those butterfly g 67 g z & LU _l LU o < FfG. 4— THIS SIMPLE INCLINOMETER can be created by using nothing but a plumb bob and a protractor. You sight along the base of the protractor base and then read the angle. FIG. 5— AN ELECTROLYTIC LEVEL is one older electronic inclinometer. As the de- vice tilts, the bridge resistance between the sensing pins will change. Bromine is one possible liquid. FIG. 6— CAPACITIVE LEVEL SENSOR is the one most often used today for elec- tronic levels and inclinometers. As the de- vice tilts, the high dielectric constant of the liquid will change the differential ca- pacitance on the plates. plates will be immersed just as deep in the dielectric liquid. As the sen- sor tilts, one plate goes deeper and the other will become shallower, thus changing the capacitance. The higher the dielectric constant of the liquid compared to air, the more profound the capacitance change. To sense, you let each wing of the butterfly set your pulse width of a monostable built out of a pair of 555 timers or one single 556 and mea- sure the time difference between the two to determine the angle. To get fancier, place a pair of the sensors back-to-back and sharing a common ground. That gives you two big advantages: First, your sensed capacitance change is now doubled, which should give you more accuracy. Better yet, your cross axis sensitivity should drop dramatically. That will happen be- cause an unwanted forward or re- verse tilt increases the depth on one side and decreases it on the other. The shape of the plates deter- mines the linearity of the capaci- tance versus the slope angle. 5ometimes, you may like to pur- posely change the plate shape to get a non-linear response. One use might be to automatically calculate compound miter cut depth on a ta- ble saw. It seems to me that you could easily make up a capacitance sensor using nothing but a pair of printed circuit boards, a spacer and a large O-ring. The bottom board would form the ground plane. The spacer would have a hole in it somewhat larger than the O-ring and would act as a compression stop, setting a fixed width. And the top one would have the butterfly pair on it. Er, on second thought, why don't you tell me? For this month's con- test, either (A) show to me an emi- nently hackable design for the capacitance inclinometer, or (B) dream up a new use for an elec- tronic angle measuring device. There will be all the usual incredible Secret Money Machine book prizes, with an all-expense-paid (FOB Thatcher, AZ) tinaja quest for two going for the best entry of all. New tech literature A brand new form of matter known as an aerogel got written up in the February 16th, 1990 issue of Science, page 807. Aerogels are rigid inorganic solids that have roughly the density of air and look like so much solidified smoke. They transmit light but block heat, elec- tricity, and sound. You can make aerogels from mine tailings dumps. Important early uses are expected to be brand new types of superinsulation and for the live capture of meteors. Neat stuff. The new Data books for this month include the Dafa Communi- cations Handbook from National, a Memory Data Book from Sharp, and a Discrete Semiconductor Con- densed Catalog from Philips. Free samples of their new 75ALS176 differential bus trans- ceivers as well as their new Widebus family chips are available from 7exas Instruments. The folks at R&D Elec- tronics have an interesting new sur- plus flyer which includes cheap ul- trasonic motion detectors and lots of assorted hacker project cases. A wide selection of new and used an- tique radio vacuum tubes is avail- able through Don Diers. And, rebuilt military infrared viewers are available from Sfano Components. One of the more popular CAD/ CAM circuit-analysis programs for the high-end engineering worksta- tions goes by the name of SPICE. For this month's free new software, nearly all of those integrated-cir- cuits houses are crawling all over themselves to see who can get their free SP/Cf macromodule simulation disks out there firstest and fastest. Early entries include Linear Tech- nology, PMI, and Motorola. The free Linear Technology disk includes a simulation and mac- romodel of their ultra-low-noise op- amp we looked at last month. Addi- tional info on SPICE often shows up in the free engineering design trade journals, such as MicroCAD News. A free Designing With Plastics; The Fundamentals booklet is ob- tainable from Hoechst Celanese. Turning to my own products, I am now self publishing nearly a dozen titles using my new book-on-de- mand PostScript technology. Four of them that you might find interesting are the Hardware Hacker II reprints, my Ask The Curu volumes I and II, and my brand new LaserWriter Se- crets book-disk combo. I've also started up a major new PostScript and desktop publishing BBS on Genie. Our goal is to have a thousand free downloads very soon. Finally, I've got a new and free mailer for you that includes dozens of insider hardware hacking secret sources. Write or call for a copy. R-E 6a PXO-1000 WITH ROTARY-SWITCH programming and a diode matrix. PXO-1000 FREQUENCY DIVIDER with DIP- 8 witch prog ramming. BUILD A GENERIC POWER SUPPLY using this PC board. Do You Know the ABC's of Camcorders? Mertl&nt* can LasL ■ lifetime when you nave i eaffleonJer by your side. Today'* camcorder* arc smilter and lijhter than ever before, and have d vjnety oF Features that make it eajitt to preierve *ucri mcraoritj » fOUI child'* rirJt birthday party ar a family reunion. The following qui; will tell you how much you know about camcorders. Score 10 pOinU for each question you answer tCHTctdy 1* Which of The following is not a consumer - Q, What it the purpose of a flying erase head camcorder formal? on a cimcardcT* (ij Bera fa) Faster erasing of tapes (b) VKS-C (b) Smoother transitions between scent* fc) 6mm (c) Longrr recording capability (d) Brighter colors (d) VH5 (*J All of ihe tbovc arc camcorder formats 7. What does tt mean when a c*m«»fckr his 2.. Camcorder* ire becoming more popular t tow lux rating? (a) The camcorder can nen he used *| every year. How many eajneordert wtt* sold! excessive heights m 19091 ibi The camcorder's controls ire located (a) ] r 4#S,W9 Or) the lower half of the unit f b? 4,290.000 (c) The camcorder can be Uicd in low £c) 6.J00.20I light vi i uj 1 1 ... r.j. Cd) 2300.000 id) The camcorder can only b* Ulcd in a 3- The best'Sclling type of camcorder li 8. True or false. Headcleane.nl ire: not {b) innm necessary (or camcotdcia. ft) Full*n VHS CcOtkCT 9* Camcorders -were ftm demonstrated to 4, Which of che following ire frsiure* found (i) 1933 on a ... j ; in . ■ i de 1 ' fb) 1962 fa) rWer loom ;.-i i960 Ibi Automatic focus (e) iking erue heads (d) Highspeed jhuiter lU* A vi ne cy of camcorder fonrua. [e] All of the above including Super VHS*C. ED Bell and High 5* The elmm format u the tastes* (lowing horizontal resolution of between +00 and 500 segment of today s camcorder market. Es it lines. This means that Conaumen experience: possible io play an km videotape at home if fa] Improved picture quality I'b'i A choice of black and white Of color ("J So pfctuni ■'O Darker pictures (b) Yes - simply connect your Bmrn camcorder 10 ihe Input* oal your jv (d) Better sound television r js. MffPl Ulk Ekdranic uumtrfn UwcJiUon * Li iajj DM— — fjM fcWf *U q!5 Utt 9 K P ft mEm<2rson= 286 AT COMPUTER WITH VGA MONITOR AND SOFTWARE AS"- I . MG0% IBM compatible. ■ 80286 microprocessor (operates at 12MHz). * One 3-1/2" 1.44 MB Happy drive. * One 5-1/4" 1.22 MB Happy drive. * 40 MB hard drive (.IDE hard disc drive]. * 1 MB RAM on motherboard expandable to 4 MB. J ■ 14" VGA .41 dot pitch high resolution color monitor. 256 colors, » VGA color card, ■ Four "r'6'bit expansion slots open. - Two RS232 serial pons. * AT compatible. * One parallel port. ■ One mouse port. ■ One half height drive exposed. ' One half height drive cavity enclosed. * 80287 math co -processor socket. * AT-style 101 keyboard, * Zero wait stale. ' 180 watt switch able power supply. * Real time clock/calendar. * One Year Parts Warranty! ■ 120 Day On-Site Servicing Warranty! * Factory New! Factory Perfect! Software includes: - MS-DOS 3.31 . - Turbo PascaE 5,0. * Borland Quatlro. ■ GW BASIC. ■ PFS Professional Write. * Emerson Menu/ Tutorial Program. ■ Check Free- Due to a special ar- angement. we were able to obtain a large inventory of hese 366 comput- As ! ii-n.ilLv.v- can now offer them you at HUGE SAVINGS! Mfr. Sugg. Retail: $3,350.00 wAVJiiitigim 99 $1499 Item No. B-2022-1 39964 Insured Ship/Hand.: $40.00 I FOR FASTEST SERVICE CALL TOLL FREE 1-800-729-9000 VISA MasterCard DAMARK INTERNATIONAL, INC. S707 Shinjte Cr«k Parkway. Minneapolis, MN 55430 Customer Service ■61^566-43*0 Please rush me: Emerson Computer(s) @ $1499.99 each, plus $40.00 s/h each. Item No.B 2022-139964 MN res. add 6% sales tax. Name Adai&as , . City .State-Zip □ ChBduMO □ VISA n Master Card U Dseover Cord No E*p Data. Signature . DELIVERY TO 48 U.S. STATES ONLY —£ Ph. # ( Drawing Board Finally, a video signal! ROBERT GROSSBLATT, CIRCUITS EDITOR w o z o o Lii ONCE UPON A TIME, VOU COULD GET into electronics without having to spend a lot of money. A pair of pliers, some wire, a busted radio, and a soldering iron, and bingo! — three days later you'd have a varia- ble interossiter (and who remem- bers what that was?). Well, unfor- tunately, things change. Variable interrositers went the way of tubes and Metal una is as far in the past as it is in the future. A real interest in electronics today means having to dig deeper into your pocket. Even though the video circuits we've been working on together are only simple ones to demonstrate basic ideas, you really need more than a multimeter and power supply to learn from it. There's often just no way to get by without an os- cilloscope. It's particularly valuable when you're doing video stuff be- cause, when something doesn't work properly the first time, you can look directly at the waveform and immediately see where you've got a problem. Now, I know that "inexpensive" is a relative term, but there are scopes advertised in R/E that can be picked up for under $300. You may be lim- ited in bandwidth and short some of the bells and whistles found on more expensive models but, unless you're doing some gee-whiz rocket- scientist type stuff, a scope with a 30-MHz bandwidth is more than ad- equate for a great many applica- tions^ — including video. I've made a point of illustrating things step by step so far, but draw- ings can show only so much — and they can show you only what things look like if everything is working OK. Since we all know that the chances of that happening first shot out of the box are about as good as finding intelligent life on Pluto, the drawings won't be representative of the waveforms being produced on your breadboard. And, if that isn't enough, not having a scope to start with means you don't have any way to tell how close your circuit is to the drawing in the first place. The classic chicken and egg problem — but one that's easily solved by getting a scope. So where were we? Believe it or not we're almost finished with our video circuitry. I'm the first one to admit that it's grown to occupy lots of real estate on the breadboard. If you find that upset- ting, remember that in the bad old days before IC's, sync generators like the one we're building took up a lot more room, and cost a whole lot more than a handful of IC's. There are IC's available that can replace most of the hardware we've been assembling. However, as with most special-purpose IC's, the price you pay for using one dedicated IC in place of some MSI stuff is a loss of circuit flexibility. Since we're designing the timing generators and one-shots, we can set the pulse widths, delays, and scan frequencies to be anything we want. Admittedly, we're after NTSC, but it wouldn't take a lot of modi- fication to generate PAL, EGA, VGA, or any other type of video we want. Also, building a sync generator can show you a lot more than just how video works — it can also show you how to make video not work. That isn't as screwy as it sounds, si nee having video not work is exact- ly what happens when the friendly folks at your local cable company scramble a channel, or when the latest videotape is copy protected in some way. I'm not saying that the circuit we're building will solve those things, but it will help you understand what's going on. And that's the first step to coming up with a solution. More on this in- triguing subject later — now it's time to put the finishing touches on the hardware. Making video Everything we've done so far has been aimed at generating the two sync pulses that are being produced at the outputs of the 4528. Both the horizontal and vertical pulses are needed to control the deflection cir- cuitry in the TV, but they have to be combined into a composite signal in order to be used to make NTSC- compatible video. And we have to make provisions in the circuitry to be able to add some picture infor- mation to the signal, as well. Even though video is usually thought of as an analog signal, the sync component is essentially dig- ital. After all, it's really nothing more than either high or low. So there are several ways we can combine the separate sync signals, such as re- sistors and diodes in a home-made Mickey Mouse gate arrangement, standard gates, and others. The choice is really yours. Even though both of our sync sig- nals are being derived from the mas- ter clock, they're being generated by separate circuitry using the two 70 halves of a 4528 (Radio-Electronics, May 1990). And since we're produc- ing a vertical sync pulse that's three horizontal lines long, the horizontal sync generator is going to keep pro- ducing pulses even during the time that the vertical sync pulse is being generated. In order to avoid potential prob- lems, we can prevent that from hap- pening by putting a low signal on the clear inputs (pins 3 and 13) of the 4528. That prevents the inverted out- puts (pins 7 and 9) from going low. (Remember that the sync pulses are active low.) The simple way to make sure that only one type of sync pulse is gener- ated at any one time is to modify the connections made to the 4528 as shown in Fig. 1. By gating the vertical sync generator with horizontal sync and the horizontal sync generator with vertical sync, there's no pos- sibility of signal conflict. During the period that vertical sync is being produced, the horizontal sync gen- erator is disabled. There's really no syWC O r^ /6 +IN our jrcs-a. _?".2 TV G*JO L * v* — H ( * * Is JOM. t3 /a/ CLM FIG. 1 reason for us to do the same thing to the vertical sync but it can't hurt anything, so we might as well. If you have a scope, you can try it both ways and see how it works. Since we've eliminated the pos- sibility of having two different sync signals show up at the same time, we can safely produce a composite sync signal. For reasons you'll see in just a second, I like to use gates. The requirements aren't very strict since VEXT/GAL- sync o- PULSE. ^y/va. JT COMPOSITE. 5/&A-AL. TC TVPE---5ES. TEyCT FIG, 2 £qot 5K. yv i — wv "=■ Zoo^- FIG. 3 -i-O-* /S0SL. -OtfTSC V/DBO we've made sure that both signals can't be low at the same time. We want a low to be produced only when either of the sync signals go low — the rest of the time we want a high. You would think we can use a simple and gate but, as it turns out, it's easier to first produce an inver- ted version of sync. That's because the inactive sync level (5-volts) has to be at IRE, or about 0.3-volts DC, and the easiest way to translate lev- els is with a bunch of resistors and a transistor. And, the transistor will in- vert the signals applied to the base (since it operates as a switch), so we're better off feeding it with an inverted version of sync. By the way, there's no reason why you can't use the non-inverting out- puts of the 4528 and feed those into an and gate to combine them. I used the inverting outputs because I pre- fer to have nand gates on the board. You never know what you'll be adding to the circuit, and inverting gates are more useful. Even though Fig. 2 uses a 4093 to combine the sync signals, you can use a 4011, or any other plain nand gate. The 4093, however, is a Sch mitt-trigger part and will pro- duce nice, crisp pulses, even if there's a bit of noise at the inputs. Since noise is always a potential problem on solderless bread- boards, it's better to be safe than so fry. All that's left for us to do is design a circuit to translate the digital sig- nals to NTSC standard. Remember that right now our circuit is making a 5-volt swing, and that is slightly beyond the NTSC-standard 1-volt range.. .to put it mildly. The circuit shown in Fig. 3 will take the composite sync at the out- put of the 4093 and cut it down to NTSC levels. You can use the trim- mer to fine tune the voltage level at the output. Just remember that the high (inactive) part of the signal should be at 0.3-volts DC to meet the NTSC specs. Now that we're producing a signal that can be fed into any video input, we can start to play around with it. Try putting video on the screen and seeing what can be done to scram- ble it. When we finish this off next month, you'll have a really good idea of how to look at broadcast video. In the meantime, try to get your hands on a scope (if you don't have one already), and take a look at what's fed into the back of your TV set. By the way, most scrambling methods aren't really that compli- cated, and as soon as you see what's been done, you can figure out what you have to do to fix it. Now that really sounds terrific. R-E 1 1; \k\ viii CLEANING/MAINTENANCE/REPAIR EARN UP TO $1000 A WEEK, WORKING PART TIME FROM YOUR OWN HOME! THE MONEY MAKING OPPORTUNITY OF THE 1990S IF you are able to work with common small hand tools , an d are f ami I i a r with has i c elect ro n i cs ( i e . a Ij I e to use voltmeter, understand DC electronics). . . . IF you possess average mechanical ability, and have a VCR on which to practice and learn. , . .then we can leach YOU VCR maintenance and repair! FACT: up to 90% of ALL VCR malfunctions are due to simple MECHANICAL or ELECTRO-MECHANICAL breakdowns! FACT: over 77 million VCRs in use today nationwide! Average VCR needs service or repair every 12 to 18 months! ViejO'S 400 PAGE TRAINING MANUAL (over 500 pho- tos and illustrations) and AWARD-WINNING VIDEO TRAINING TAPE reveals the SECHETS of VCR mainte- nance and repair— "real world" information that is NOT available elsewhere! Also includes all the info you'll need regarding the BUSINESS-SIDE of running a successful service op- eration! FREE IHFfJRMATI0H CALL TOLL-FREE 1-800-537-05B9 Or write to; Viejo Publications Inc. 3540 Wilshire BL. STE. 310 Los Angeles, CA 900)0 Dept. RE CIRCLE 181 ON FREE INFORMATION CARD C 2 m CO CO o 71 Audio Update Receivers vs. separate components LARRY KLEIN, Audio Editor CO o z O ec t~ o LU _l LU o □ < 72 IN A SENSE, THE RECEIVER IS THE COMPO- nent that separates audiophiles from "mere" music listeners. (Or, if you will, the men from the boys.) Music listeners own receivers; au- diophiles don't. At one time, the decision to go for separate compo- nents {tuner, preamp, and power amplifier) instead of an all-in-one re- ceiver was a rational choice, but time and technology have shifted the parameters of the ballgame somewhat. So for readers shopping for an amplifier and tuner either to upgrade some older equipment or as a first-time buy, here are some historical notes and pros and cons to be used in making the receiver vs. separates decision. Audio evolution When hi-fi left the labs and broad- cast studios and went public in the early 1950's, the early audiophile could choose dozens of tuners and numerous amplifiers in various con- figurations. Some power amplifiers had "remote" preamplifiers at- tached via a powering cable; others were available as integrated ampli- fiers or as separate power amplifiers with output powers ranging from 8 to 22 watts. However, all-in-one re- ceivers were very rare, possibly re- flecting an effort to differentiate the early hi-fi components from the various large, multi-tube radio chas- sis that were also available for do-it- yourselfers. By the time stereo records ap- peared in late 1958, receivers were an established alternative format whose single chassis was easier to install and cheaper to manufacture, FIG. 1— INTEGRATED CIRCUITS give you a lot more watts for your dollar. and eliminated the tangle of unrelia- ble interconnecting cables. How- ever, if you wanted appreciable power from both of your stereo channels, the receiver had a prob- lem. Remember that all equipment in those days used tubes, and power-output tubes required out- put transformers. Wide-range, low- distortion output transformers were necessarily large and heavy — as were the power transformers sup- plying the filaments and the plate currents of the four output tubes. This meant that stereo receivers tended to be large, hot, and heavy. And if you wanted powers higher than about 20 watts, they got signifi- cantly larger, hotter, and heavier. I remember one moderately high- powered and expensive Fisher re- ceiver that struck me as an effective advertisement for separate compo- nents — it took an incredibly strong man to lift it! Transistorization Aside from the other benefits wrought by the transistorization of audio, it brought high-power re- ceivers into the realm of practicality. The low output impedance of the power transistors eliminated the need for the two output transfor- mers. That in turn not only enabled the designers to reduce the cost, weight, and size of their products but also served to improve amplifier bandwidth and stability. The ampli- fier and tone control stages also benefitted from the low impedance of the solid-state circuitry; the hum and RFI problems that had always plagued high-gain tube circuits were substantially reduced. The net result of all those advantages — plus the cost reduction that resulted from the use of a single chassis and power supply — was that the re- ceiver shortly became the best-sell- ing electronic audio component. The elements of choice Given all the factors discussed above, why haven't separate power amplifiers, tuners, and pre- amplifiers vanished from the mar- ketplace? There are several non ra- tional reasons why otherwise ra- tional audiophiles (myself included) prefer separates. A few words about the irrational elements first. It didn't take years on a psychoanalyst's couch for me to realize that there's some snobbery at work in at least two areas of my buying behavior. For example, I've always used the inadequate perfor- mance and poor reliability of U.S. continued on page 79 Compu7ErDicesi BUILD THIS EXPERIMENTER'S I/O CARD A computer by itself can't do iVmuch; it needs some way of communicating with the outside world. It needs to be able to sense external conditions (a switch clo- sure, for example), and it needs to be able to control circuitry (a relay, for example). The princi- ples of interfacing those types of devices are not difficult; we'll show how easy it is by building an experimenter's card for the IBM PC expansion bus. The card contains three eight- bit parallel ports, but is built from just a few components, thereby making construction simple and inexpensive. We'll de- scribe several circuits for inter- facing LED's, switches, and other devices to the card, as well the software required to configure and use the I/O ports. Well also show you how easy it is to set up and use the card with simple BASIC programs. The 8255 PPI The heart of the design is the 8255 Programmable Peripheral Interface, or PPL The 8255 was originally designed for use with the 8080 microprocessor, but it is also used with 8088 designs including the PC family. The 8255 has three eight-bit TTL-compatible I/O ports (A-C), and it can operate in three dif- ferent modes. Depending on the mode, the lines in each port act differently. In Mode 0, Ports A and B can operate as either inputs or out- puts, and Port C is divided into two four-bit groups, either of which can operate as inputs or outputs. In Mode 1, Ports A and B can again act as either inputs or out- puts. However, the two four-bit ports in Port C are used for hand- shaking and control purposes in conjunction with Ports A and B. In Mode 1, the Port C lines might be used to strobe data (supplied on either Port A or port B) into a printer, and to detect its "busy" signal. Last, in Mode 2, Port A is used for eight-bit bidirectional bus 1/ O, Port C is used for control and status information, and Port B is not used at all. For further details on operating modes, consult In- tel's Microsystem Components Handbook, Volume 2. You select among the various modes by writing a value to a spe- cial control port; Table 1 shows the control-port values required to achieve various I/O combina- tions. Our examples all work in Mode 0. The PC interface With Intel microprocessors, communications between the CPU and various devices is ac- complished through I/O (Input/ (Continued on page 75) EDITOR'S WORK^ Bench 68000 News I heard from an old friend, Peter Stark, recently. Peter is one of the world's more accomplished 6800/68000 hackers. You may re- call his series on building a 68000 computer that uses IBM- PC style display adapters, I/O cards, case, keyboard and power supply. The series ran from May 1987 to September 1988, and PT-68-K2 kits are still available (see Vendor Information below for more information). Peter wrote the operating system that controls the PT-68-K2. Anyway, it seems that one of the older 68xxx magazines has cut coverage of hobbyist/hacker systems, so Peter is beefing up his own newsletter, trying to take up the slack. If you're interested in 68xxx systems, contact Stark- K Software Systems Corp., EO. Box 209, Mt. Kisco, NY 10549. Tell 'im I sent you. System Analyzers What's inside your home com- puter? You're probably inti- mately familiar with it. But what about your office PC? What about your coworker's PC (you know, the cute little blond who's always coming to ask you for advice)? What about the six, twelve, or hundred PC's that you provide service and support for? Maybe ^ you know, maybe you don't. Most z of the time you don't care, but -* when you're installing new hard- g 73 CO o o 2 o Q Q < ware or software, you do care, desperately. Several products have come to market recently that purport to provide useful in- formation on PC internals: Sys- tem Sleuth 2.0 (by DTG) and Manifest (by Quarterdeck Office Systems). Manifest's main purpose is to help optimize memory usage; System Sleuth provides most of the information that Manifest does, along with a wealth of infor- mation on other PC subsystems, as well as several useful utilities. Manifest can display the con- tents of just about all types of sys- tem memory, including conven- tional, extended, expanded, and even the CMOS memory in ATs. Of course, the program doesn't just provide raw hex dumps; in- stead, it provides nicely format- ted, organized listings of memory usage, interrupts hooked by vari- ous programs, I/O port usage, and more. The program pops up on- screen in several panels. You move a pointer up and down a list in the left panel to select the type of memory, and left and right in the upper panel to select par- ticular details of that type of memory. You can also make your selections with a mouse. Manifest's most useful display shows how interrupts are used by programs located in the first megabyte of memory. For exam- ple, in Fig. 1, you see the hex seg- ment in the left column, the program located there, and the interrupts it claims last. By pressing F3, the display changes to a sequential listing of inter- rupt vectors (00-FF), the address in memory where each vector points, and the program that "owns" that vector. You can load Manifest as either a transient program or as a TSR. In the latter case, the program uses more than 100K of memory, but it could still be useful when trying to track down competition for interrupts among several dif- ferent programs. System Sleuth provides a sim- ilar display, as shown in Fig. 2. System Sleuth also provides a se- quential listing of interrupt vec- tors, but without addresses and owners. Quarterdeck MANIFEST Overview Programs BSIBMTO^ BIOS Data Timings ystem First neg 4 Expanded Extended OS Fi=Help FZ=Frint 9070: 10 01 03 01 OF 13 19 IB 29 ZF 827D : MSDOS 00 20 25 26 27 Z8 2A ZB 2C 2B 32 33 34 35 36 37 38 39 3fl 3B 3C 3D 3E 3F 0BD2 : DOS Stacks 02 OB 09 0E 70 76 GC9F: COrTONB 22 23 24 ZE 0DB9: FZF 05 1C 21 C00O: Uideo ROM IS ID IF 43 6B F0GE3: System ROM 06 07 0A 0B 0C 01 11 1Z 14 15 16 17 18 1A 40 41 4Z 44 45 46 47 40 49 4A 4D 4C 4B 4E 4F 50 51 52 53 54 55 56 57 50 59 5A 5B 5C 5B 5E 5F 60 69 6A 6B 6C 6E 6F 71 72 73 74 75 77 Press F3 to 1 ist by Number PIG. I FIG. 2 Manifest provides a nicely for- matted display of the BIOS data area (0040:0000); System Sleuth doesn't do that, but it does pro- vide a hex/ASCII display routine that lets you view any area of memory beneath 1 MB. Manifest measures the access speed of various areas of memory (0-640K, video RAM, video ROM, etc.) and reports values relative to a stock PC/XT. System Sleuth has nothing comparable. Manifest also shows each byte in CMOS memory; again, System Sleuth has nothing comparable. All in all. Manifest has more powerful memory reporting and ratings capabilities. On the other band, System Sleuth includes functions for re- porting on hard disk drive health. Various menu items pro- vide information on the number of disk drives, and the physical characteristics of each drive ( things like bytes/sector, sectors/ cluster, sectors/track, etc.). You can view a hex/ASCII dump of a disk file, and even test a disk for bad sectors. System Sleuth also includes 74 several external utility programs, including one that finds files across multiple disk drives, an- other that searches for duplicate file names (also across multiple drives}, another that deletes files with certain file names (*.bak, *.tmp, etc.), routines to save and get the data stored in CMOS memory, and an EMS emulator thai uses 286 extended memory. The company is adding addi- tional utilities all the time; they tell me a disk cache is next. I ran Manifest and System Sleuth on several different ma- chines, and had problems with both programs on my AST Pre- mium/286. It has built-in EMS 4,0 hardware that is controlled by AST's EMM driver. I also use a memory manager called Move 'em (made by gualitas, the 386MAX people) to load several device drivers and TSR's into high mem- ory (above the video adapter but below the 1 MB mark). The prob- lem was that I simply could not run either Manifest or System Sleuth on the AST with Move 'em installed; the machine crashed every time. That's completely un- acceptable: no diagnostic pro- gram should ever crash any machine. However, I had no trouble run- ning either program on several other machines, including a Tan- dy 1100 FD "notebook" computer, a Dell System 300 (386), and a 33-MHz Intel 386 system. (Both 386's were running 386MAX.) In- terestingly, both programs were smart enough to figure out that the CPU in the Tandy is a V20, not an 8088. I learned a few tricks from Man- ifest's "Hints" section. One showed me how to map another 32K of EMS memory into an un- VENDOR INFORMATION • PT-68-K2 (68000 kit prices start at $200), Peripheral Tech- nology, 1710 Cumberland Point Drive, No. 8, Marietta, GA 30067. (404) 984-0742. CIRCLE 271 ON FREE INFORMATION CARD • System Sleuth 2.0 ($149. 95), DTG, 7439 LaPalmaAve., Suite 278, Buena Park, CA 90620-2698. (714) 994-7400. CIRCLE 272 ON FREE INFORMATION CARD • Manifest ($59.95), Quarter- deck Office Systems, 150 Pico Blvd., Santa Monica, CA 90405. (213) 392-9701. CIRCLE 273 ON FREE INFORMATION CARD used area of the VGA video adapt- er range and thereby load a TSR up there. Another saved me about 3K of additional low DOS memory. All in all, I now boot with about 130K of TSR's, but still have 592K of free contiguous DOS memory, all with a VGA adapter that runs graphics just fine. Reports Both Manifest and System Sleuth can print partial or com- prehensive reports of their find- ings. You must print System Sleuth's reports via the menus, but you can get them from Man- ifest either via the menus or in a command line mode. For exam- ple, if you start the program like this: CMFTSO you'll get a listing to the screen of the System Overview; similar re- ports are available for each cate- gory and sub-topic, or all categories and sub-topics. The command line mode could be useful if you wanted to print re- ports for several PC's. Just create a batch file with the desired com- mand lines and then run it on each machine. Both programs come with on- line help. Manifest's help system consists of a single screen of in- formation for each topic; System Sleuth includes qtiite a bit more information, mostly tutorial in nature, that should be useful for those still getting up to speed on device drivers, different kinds of memory, etc. Of course, the infor- mation provided is no substitute for an IBM Technical Reference manual. Manifest comes with a very well written and produced manual that ls*tutorial In nature. System Sleuth's manual is not so well produced, and it mostly dupli- cates the information in the help screens. However, if you know a little about DOS, both manuals are superfluous. All in all. Manifest's strength is information about memory; Sys- tem Sleuth takes a more systema- tic approach. Manifest's user interface and documentation is also more polished. But where it counts (resolving interrupt con- flicts), both programs deliver. System Sleuth lists for about $150, and Manifest for about $60; I've already seen Manifest discounted via mail order to about $40. It may be worth pointing out that neither program will help with the truly tough problems: machines that won't boot, hard- ware conflicts between adapters trying to use the same interrupts or I/O ports, etc. There you'll be forced to dig out manuals and compare and contrast jumper and DIP switch settings >CD| I/O CARD continuedfrom page 73 Output) ports. Just as each house on a street has its own ad- dress, each piece of hardware connected to an Intel processor has its own port address. For ex- ample, serial port COM1 is lo- cated at address 03F8h. IBM's Technical Reference Manuals list the specific port addresses asso- ciated with specific pieces of hardware. Our project uses 32 port ad- dresses between 0200h and 02FFh. In order to avoid conflict with other devices, those 32 ad- dresses can start at one of eight locations in that range; you select the desired starting address via a jumper block, as shown in Table 2. Both hex and decimal values are shown; if you're program- ming in BASIC, you'll probably find the decimal values useful. As shown in Fig. 1 , the address ranges are decoded by IC2, a 74LS138 demultiplexer. The 74LS138 takes three inputs and decodes the various combina- . tions thereof into eight exclusive g outputs. The IC also has one ac- m tive-high (gi) and two active-low g (G2A and C3E) enable inputs. ° 75 TABLE 1—8255 PORT CONFIGURATION Control Word Port Hex Decimal A B C 80 128 Out Out Out 82 130 Out In Out 85 133 Out Out In 87 135 Out In In 88 136 In Out Out 8A 138 In In Out 8C 140 In Out In 8F 143 In In ,„ TABLE 2— JUMPER POSITIONS AND PORT ADDRESSES Position 1 2 3 4 5 6 7 8 Hex 200 220 240 260 280 2A0 2C0 2E0 Address Decimal 512 544 576 608 640 672 704 736 o z O BP135 — A beginners guide to the Commodore 64 pre- sents masses of useful data and programming tips, as well as describing how to get the best from the powerful sound and graph- ics facilities. We look at how the memory is organized, random numbers and ways of generating them, graphics-coior-and sim- ple animation, and even a chapter on ma- chine code. Get your copy today. Send S5.00 plus S1.25 for shipping in the U.S. to Electronic Techology Today Inc., P.O. Box 240, Massapequa Park, NY 11762-0240. IC PROMPT DELIVERY!!! SSAME DAY SHIPPING (USUALLY) QUANTITY ONE PRICES SHOWN F°r APRIL 1. IttO OUTSIDE OKLAHOMA NO SALES TAX DYNAMIC RAM 1 MB COMP DbssP'O 336 20 $295.00 SIMM AST Prem3S6i33Mhz 225.00 SIMM 1Mx9 80 ns 95.00 SIMM 25BKx9 100 ns 38.00 1Mbit IMxl SO ns 9.25 41256 256Kx1 60 ns 4.50 41256 256Kxt 80 ns 4.15 41256 25SKxt 100 ns 3.50 41256 256KXI 120 ns 2.70 4464 64Kx4 100 ns 3.50 41264* 64KX4 100 ns 7.50 EPROM 27C1000 t28KxB 200 ns 318.00 27512 64Kx8 200 ns 7.80 27256 32Kx8 150 ns 6.50 27128 16KX8 250 ns 3.75 STATIC RAM 52256P-10 32Kx8 100 ns S9.50 6264P 2 SKxB 120 ns 4.50 6116AP-12 2Kx8 120 ns 4.25J OPEN 6 DAYS. 7 som 10™ SHIP VIA FED-EX ON SAT HXt DEUVERY trtCLUJDED DIM FED>£X ORDERS HECEfYED DY: TTc M UBit IV; M 5 ILK I ft WastflrCnrd''ViSA Of UPS CASH COD MICROPROCESSORS UNLIMITED, INC. 2*J,CK» S Pwrin Ave " aeGGS. OK 74-121 No minimum ardor, Phti-^b nola |>-:*a ii^ki la thirty* 1 (918) 267-4961 CIRCLE 61 ON FREE INFORMATION CARD ing construction, it's best to use sockets for all IC's. Neither IC used in this project is par- ticularly sensitive to static damage, but you can never be too careful. The author found it con- venient to use red wires for power and ground connections, white for bus connections, and blue for connections from the 8255 to the output connector. Start with the 6 wires that run from the bus connector to IC2. (By the way, looking at the com- ponent side of your mother- board, the "B" side of each expansion slot is on the left and the "A" side on the right, and the connectors are numbered from 1 to 31 from the rear of the board to the front.) Take your time, and check each solder joint for shorts with adjacent pins. Then connect the eight wires from IC2 to the jumper block, continue with the eight data-bus wires from the bus connector to the 8255, then the six control wires to the 8255. Then connect the 24 wires from the port out- puts of IC1 to Jl. The author used a 40-pin header connector for Jl in the prototype. Many projects require a source of +5 volts, so power and ground lines are also brought to Jl. PARTS LIST IC1— 8255A-5 parallel Interface IC2— 74LS138 3-to-8 line decoder C1-C3— 0.1 \xF J1 — 40-pin header connector Jumper block (2 rows, 8 positions) PC bus prototyping board Sockets, wire, etc. Programming examples The following examples as- sume that the jumper is in posi- tion three, so that the 8255 is connected to port 0240h. When power is first applied, ports A, B, and C are all config- ured as inputs. To reconfigure the port, you must write the ap- propriate value to the correct port. For example, by connecting eight LED's to Port A as shown in Fig. 3, you could view the binary counting sequence using this program ; 10 OUT 579,128 20A = 30 OUT 576, A 40 A=A+1 50 IF A 255 GOTO 20 60 GOTO 30 If one LED doesn't seem to light, run this program: 10 OUT 579,128 20 OUT 576,255 All of the LEDs should light. If one doesn't, check your wiring. Reading input values is just as simple. The following program would continually read and dis- play the contents of port B, to which various switches (Fig. 4-a, Fig. 4-b) and sensors (Fig. 4-c) might be connected: 10 OUT 579,130 20A = INP577 30 IF A 40 GOTO 20 That program sets up Port B for input, and then reads the value of the port. If the value is less than 255 (in other words, if at least one line is low), the value is printed. The 8255 's inputs and outputs are TTL compatible, meaning they don't have much current- carrying capacity To drive heav- ier-duty devices, use a transistor, as shown in Fig. 5-a, or add a relay, as shown in Fig. 5-b. More Ideas c Now that you understand the m basics, the sky's the limit. What £ else could you do? o 77 ELECTRONICS PAPERBACKS n BP117— PRACTICAL ELECTRONIC BUILDING BLOCKS, BK-1 S5.7S. Circuits for a number of useful building blocks are presented. Combine these circuits to build the devices you need. HI BP192— MORE AD- VANCED POWER SUP- PLY PROJECTS $5.95. Topics covered include swilched-mode power sup- plies, precision regulators. dual tracking regulators and com p ut e r-con I rot I ed su p- plies. More Advanced Power Sua ply Project! □ BP190— MORE AD- VANCED ELECTRONIC SECURITY PROJECTS $5.95. Projects include a passive inlra-red detector, a fibre-optic loop alarm, computer-based alarms and an ultrasonic intruder detector. [1 BP113— 30 SOLDER- LESS BREADBOARD PROJECTS, BK-2 £5.95, All projects are based on CMOS logic ICs. Many components are common to several proj- ects. Each project includes a brief circuil description, component layout and parts list. EtoetrortTe ["I BP74— ELECTRONIC MUSIC PROJECTS $5.95. Provides a number of circuits for Fuzz Box, Waa-Waa Pedal, Sustain Unit, Reverberation and Phaser Units, Tmmelo Gen- erator and more. □ BP255— INTERNA- | TIONAL RADIO STA- TIONS GUIDE $7.95. Provides the casual lis- tened, amateur radio DXer and tfie professional radio monitor with an essential relerence work designed to guide him or her around than ever more complex ra- dio bands. MAIL TO Electronic Technology Today, Inc. R0. Box 240 Massapequa Park, NY 11762-0240 SHIPPING CHARGES IN USA AND CANADA £30.01 to $40 00 S5.00 S40.01 lo £50,00 S6.00 $50 01 and above S7.50 $0.01 to £5.00 $1.25 $5.01 to 10.00 J2.00 $10.01 to $20 00 £3,00 $20.01 to $30 00 $4.00 SORRY, No orders accepted outside ot USA and Canada Total price of merchandise $ Shipping (see chart) $ Subtotal $ Sales Tax (NYS only) £ , Total Enclosed $ Name AtJoress . City . -Slate _Zip. ( : A0 •5V* fjt4 1 ^ — ICI-a * m >->. 27011 74mVV ED1 m A2 Jo ?■— ' 7404 ^\l-E02 R3 20 A3 27011 34 *CV^ D3 M X — 27011 FROM Jl < FIG.l A4 ICl-d ;. 74IM W\L£D4 Rb v *^» 2701} 22 A5 R6 27011 wvi IC1 1 ■7404'%/, w ,J.LED6 R7 N. Tid *— _ Tift I A6 24 A7 \\ LED: 27013 IC2-3 74tJ4 \V ED7 Ra ^ 27011 TCTTT 7404 LED8 27 ■ 2a bV mo FIG. 3— FOR OUTPUT DISPLAY, add eight LED'S, eight resistors, and two 7404 's. ,sv t i 1 INPUT SIGNAL FIG. 4— FOR INPUT, add a toggle switch (aj, a pushbutton switch (b), or an opto-isolator (c). • How about building a robot? Output ports could be configured for motor control, voice syn- thesis, robotic arm control, etc. Input ports could be used to read bumper sensors, voice recogni- tion, or keypad input. • Or build a burglar alarm: Input ports would read data from win- UTPUTS INPUT FIG. 5— FOR HIGH-CURRENT OUT- PUT, use a transistor to drive a lamp (a) or a relay (b). dow and door switches, and from motion detectors. Outputs would control lights, a siren, and a tele- phone dialer. • Or build a home heating sys- tem. One port would be dedicated to motors that would open and close heating vents, control blow- er motors, etc. Input ports would read thermometers in each room and outside the house. A real- time clock would be used to turn heat on in the morning and off in the evening. You could include a wind speed gauge, controls for a solar hot-water heater, and even calculate your energy savings. • Or build a scoreboard, a light show, or an IC tester. How about a computer-controlled popcorn popper or a dog food dispenser? The author has used his card to run a plotter, an EPROM pro- grammer, and a model-railroad demonstration. Another thing you could try building is an automatic home lighting system. Input ports could monitor doorways with pressure-sensitive switches or infra-red beams. The system would sense someone entering or leaving the room, and turn the lights on and off accordingly. The system would have to keep track of how many people were in the room, turning the lights off only after the last person leaves. For some projects, three ports may not be enough. In that case, just connect a second 8255, wir- ing all lines except cs in parallel to IC1. Connect the cs line of the second 8255 to a different posi- tion on the jumper block — and enjoy 48 lines of digital I/O! r>C»4 78 < R-E Engineering Admart Rates: Ads are 2'/V' x 2 W. One insertion $950. Six insertions $925. each Twelve rtions $895. each. Closing date same as regular rate card. Send order with ittance to Engineering Admart, Radio Electronics Magazine, 500-B Bi-County , Farmtngdale, NY 11735. Direct telephone inquiries to Arline Fishman, area 516-293-3000. Only 100% Engineering ads are accepted for this Admart. Surface Mount Chip Component — - Prototyping Kits— \ Only CC-1 Capacitor Kit contai ns 365 pieces. 5 ea. ot every 10% value from 1pMo 33nf. 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WPT PUBLICATION 979 Young Street, Suite A Wood burn, Oregon 97071 Phone (503) 981-5159 6805 MICROCOMPUTER DEVELOPMENT SYSTEM The MCPM-1 syslein allows the IBM PC and compatibles to be used as a complete development system for the Motorola MC6870SP3. P5. LIS. US, R3 arid R5 single chip microcomputer's. The system includes a cross assembler program, a simulator/debugger ptogram and a programming board that connects to a serial port, Pnce— S449.00 VISA and MASTERCARD accepted ' THE EHSIXEERS 'eatuso»ATifi. mc. RR#3, BOX 8C Barton. Vermont 05B22 Phone (602) 525-3456 RAX C602) 525-3451 CIRCLE 178 ON FREE INFORMATION CARD CIRCLE 182 ON FREE INFORMATION CARD CIRCLE IBS ON FREE INFORMATION CARD AUDIO UPDATE continued from page 72 cars to justify owning foreign-made vehicles. And to tell the truth, I'd be somewhat embarrassed to admit owningastandard U.S. family car. In the same sense, I'd feel that I had blown my credentials as an "Audio Maven" if word got around that I used a receiver in my main system. But aside from emotional pre- dispositions, what valid reasons are there for choosing separate compo- nents? Output power is one. Given the extended dynamic range of compact discs, the advantage of having at least 100 watts per channel of clean power on tap seems in- arguable. The sense of ease and openness, and the bass solidity all testify to the sonic virtues of high power. Today, the top power available in a receiver is about 130 watts per chan- nel. For many people that is proba- bly more than adequate, but for those who want their music very loud and very clean when heard through medium-to-low efficiency speakers, 200 watts is an absolute minimum. That explains why the 1990 stereo buyers' guides list doz- ens of 300- and 400-watt-per-chan- nel amplifiers. Incidentally, I have clipped a 200-watt-per-channeI am- plifier trying to reproduce a solo piano at live sound levels, so the desire for ever higher amplifier New Scanner byAOR 100 Channels 800 MHz >? AR900 Tu'il Fjicc. Ficighl Profile!. 'Enpi ut Shspptftfl Gpuorukl) $259-°° • Includes Antenna, rechargeable battery, charger / adaptor & bell clip. Full range of optional accessories available. ■ Covers 27-S4 MHz. 108-174 MHz, 4D6-S12 MHz, and BW-950 MHz. * S Scan Banks and S Search Banks. * 25 Day Satis faction Guarantee, Full Refund if not Satisfied. ■ No Frequencies cut out, • Size: IT i S W % 1 W wt: 12 oz. COMMUNICATIONS 10707 E. 106th St. Indpls., IN 46256 ^^ TollFree800-445-77I7 Visa and MasterCard i^M> [COD slightly higher) I! lnlndiana317-849.2570Colleg FAX (3 17) B49-B794 CIRCLE 193 ON FREE INFORMATION CARD power does have a genuinely ra- tional basis given certain listening circumstances. Upgrading The essence of being a totally dedicated audiophile (which I am not) is the never-ending pursuit of the holy grail of "perfect" sound re- production. In practice, that means constant upgrading — or at least re- placement- — of existing compo- nents in hopes of coming ever closer to sonic perfection. The pur- suit is encouraged by several small circulation "underground" audio magazines, such as Stereophile and The Absolute Sound. Their detailed reports on each new high-end (meaning very expensive) pre- amplifier and power amplifier be- comes Holy Writ for the dedicated audiophile seeking to determine each product's precise place in the hierarchy of sonic perfection. Page after page will be devoted to what is almost a frequency-by-frequency analysis of each audio product's sound quality. If the reviewed product appears to offer some real or imagined ad- vantage over his existing equip- ment — which was the best available only four or five months ago — the dedicated audiophile buys it as soon as his finances permit. Inci- dentally, some excellent power am- plifiers are available for about $2 a watt, meaning that a 200-watt-per- channel amp can be had for about $800. One can also spend $16,000 ( ! ) for a200-watt-per-channel amplifier, but I think that the joy of owning such a product has little to do with its sound perse. I shouldn't exclude FM tuners c z m 79 from the upgrading process, al- though most audiophiles are aware that the broadcast stations are far more responsible for tuner sound quality than any other factor. In any case, it is obvious that owning a re- ceiver makes piecemeal compo- nent replacement impractical. Re- ceivers also tend to complicate matters when something goes wrong electronically. If a separate tuner goes bad, the rest of the sys- tem is still functional while the tuner is in for repairs. And even a defec- tive preamp won't stop the music if the power amp has accessible input- level controls. The bottom line So, after all of the above, what do I recommend? As I indicated, I think it comes down to how loud you like your music and the efficiency of your speakers. If you want to re- produce music at natural volume levels, then 200 + watts per channel is what you need. But if your taste, you wife, your neighbors, or your budget doesn't permit such audio extremes, then a high-powered re- ceiver may comfortably fit your re- quirements. If possible, listen to the receiver under consideration with the speak- ers you are going to use it with. Then, listen to the same speakers at the same preferred volume level driven by a significantly higher power amplifier. If the sound quality is about the same, then a receiver is the way to go. RE o s I -I w 6 Q ADD A DISPLAY continued from page 62 TABLE 2— USER DEFINABLE CHARACTERS CHARACTER CODES CDD RAM DATA) 90900 (00 HEX) ACCESSED BY ASCII CODE 99 (HEX) CG RAM ADDRESS a ' a. CHARACTER PATTERN (CG RAM DATA) 9 9 o a 9 8 a e o a f'i i T'i a La a l_"X" o a a a a a NOSE SECTION CHARACTER CODES (DD RAM DATA) (01 HEX) ACCESSED BY ASCII CODE 01 (HEX) CG RAM ADDRESS 2 •'•■ CHARACTER PATTERN (CG RAM DATA) BODY SECTION CHARACTER CODES (DD RAM DATA) ACCESSED BY ASCII CODE 9E (HEX) CG RAM ADDRESS _i L CHARACTER PATTERM (CG RAM DATA) 1 1 ; o 9 1 1 : 1 1 1 i 1 1 1 1 1 1 1 1 1 a a a e TAIL SECTION COMPLETE AIRPLANE ORDERING INFORMATION The following items are available from Simple Design Implementations (SDI), P.O. Box 9303, Forestville, CT 06010 (203) 582-8526; Experi- menters kit (contains 16 x 1 0PTREX LCD module, programmed MC68705P3, contrast-control poten- tiometer, PC board, IC socket, soft- ware listings, schematic, and instruc- tions), $29.95 + S3 S/H; Same experimenter's kit with 40 x 1 display, $39.95 + $3 S/H; Programmed MC68705P3 and instructions, $15.95 + $2.50 S/H. shows the 24 data bytes that must be written to CG RAM to form the three user-defined characters that form the airplane. Displaying actual data Once the display has been properly initialized, displaying data is as sim- ple as writing out the proper ASCII codes with a series of Data Write oper- ations. Remember, the "SET DD RAM ADDRESS" command must precede the data operations to ensure that the data goes to DD RAM and not CG RAM. Similarly, data writes to CG RAM must be preceded by a "SET CG RAM ADDRESS" com- mand. For example, the routine in Listing 6 will display the message "PLANE" (assuming that the user- defined Character Generator RAM is set up as defined in Listing 5). Next month Due to space limitations, that's all we have room for this month. Next month we will continue our discus- sion on LCD modules, and cover some of the different kinds of inter- faces, including hardware, micro- controller, and microprocessor. R-E so MARKET CENTER FOR SALE GREAT buys! Surplus prices, ICs, linears, transfor- mers, PS, stepping motors, vacuum pump, photolransistor, meters, LSASE, FERTIK'S, 5400 Ella, Phila., PA 19120. DESCRAMBLERS. All brands. Special: Combo Jerrold 400 and SB3 S165. Complete cable de- scrambler kit $39. Complete satellite descrambler kit $45. Free catalog, MJM INDUSTRY, Box 531, Bronx, NY 10461-0531. T.V. notch filters, surveillance equipment, brochure $1.00. D.K. VIDEO, Box 63/6025, Margate, FL 33063. (305) 752-9202. MICROWAVE TV RECEIVERS 1.9 to 2.7 GHz VI5A/MC/C0D 2 CH Compact Dish System - S77.95 5 CH Dish System - S93.95 12 CH Yagi (Rod) Syslem - 5123.96 30 CH Dish Syst Em-S163.9D Yag i -S 183.90 SIM MICROWAVE INTL. INC. Send it M lor P.O. BO* 34522 calatog an thtu PHOENIX. A Z 85067 ind Mtar line |002! 230-0640 video products. OUMITIY 0I5MUNTS LIFETIME WARHANTT RESTRICTED technical information; Electronic sur- veillance, schematics, locksmithing, covert sci- ences, hacking, etc. Huge selection. Free brochures. MENTOR-Z, Drawer 1549, Asbury Park, NJ 07712. RENTAL movie stabilizer. Connect between VCRs or to monitor. Satisfaction guaranteed. $69.95, $4.00 handling. 1 (800) 367-7909. TUBES: "oldest," "latest." Parts and schematics, SASE for lists. STEINMETZ, 7519 Maplewood Ave., RE, Hammond, IN 46324. ENGINEERING software, PC/MSDOS. Hob- byists — students — engineers. Circuit de- sign $59.00, FFT analysis S69.00, Mathe- matics $49,00, Logic Simulation $49.00, Circuit Analysis $29.00. Free catalog. (614) 491-0832. BS0FT SOFTWARE, 444 Colton Rd., Columbus. OH 43207. CABLE TV converters and descramblers. We sell only the best. Low prices, SB-3 $79.00. We ship C.O.D. Free catalog. ACE PRODUCTS, PO Box 532, Dent. E, Saco, ME 04072. 1 {80S) 234-0726. SAMS closeout sale. #2 to #2600 $6.00 each postpaid. MC/Vlsa. Calll (8O0) 274-2081. 9-5 CST. PRINTHEAD repairs — Okidata. Epson. NEC. Toshiba, Digital, Texas Inst., also do board repair — DATAFIX, (201) 322-7666. TUBES Syfvania 6LQ6, 6L6GC, 20LF6 etc. Huge discounts. ARLEN SUPPLY, 7409 West Chester Pike. Upper Darby, PA 19082. 1 (800) 45B-1301. TJ SERVICES is here to serve you! Our quality products, quick courteous service, knowledgeable sales people and rock bottom prices prove it! Not sure what you need? Call (313)979-8356 we'll help! We specialize in Jerrold, Hamlin, interference fil- ters and most SA equipment. FEBRUARY 1984 project. Complete parts with power supply. $38.06. Postpaid. JIM RHODES, INC., Box 3421. Bristol, TN 37625. CABLE TV converters: Jerrold, Oak, Scientific At- lantic, Zenith & many others. "New MTS" stereo add-on: mute & volume. Ideal for 400 and 450 owners! 1 (800) 826-7623, Amex, Visa, MIC accept- ed. B & B IMC, 4030 Beau-D-Rue Drive, Eagan, MN 55122. TUBES, new, up to 90% off, SASE, KIRBY. 298 West Carme! Drive, Carmel, IN 46032. CABLE TV DESCRAMBLERS! BARGAIN HEADQUARTERS! ■JERROLD -TOCOM - HAMLIN • SCIENTIFIC ATLANTA ■ ZENITH Oak M35B ONLY $60 6 month wimnlyl We *hjp C.O.D, ! Loweit retail ."whole ■■!« prices! FHEE CATALOG: Global C«We Netwoifc 1032 Irving St. Suit* IDS S.F.. CA 94122 ORDER TODAY! 800-327-8544 MARK V ELECTRONICS, INC. QUALITY COMPONENTS * COMPETITIVE PRICES A indicates the level of difficulty in the assembling of our Products TA-36QO caflHrt- ^ TA ' 477 AMPLU'IKKS KIT ASSMB. MODEL DESCRIPTION TA-26MK2 Digital Voles Recorder u $ 30.00 TA-50/VB MuMj- Purpose Melody Generator A. 11.84 S 1658 TA-50C Multipurpose Melody Generator A 12.65 17.71 TA-120MK2 35W Class "A" Main Power Mono Amp AA 27.16 38.B1 TA-300 SOW Multipurpose Single Channel Amp A 20.00 29.00 TA-302 60W Stereo Power Booster (w/case) AA SO 00 70.00 TA-323A 30WX2 Stereo Pre-main Amp A 29 50 38.35 TA-377A Hi-duality FET Stereo Pre-Amp AAA. 59.95 75.00 TA-400 40W Solid Stale Mono Amp A __ _... 28.00 34.93 TA-477 120W Moslet Power Mono Amp AA 6800 85.00 TABOO BOW+80W DC Pre-Main S Power Amp AA 60.92 79.20 TA-802 60W+80W DC Stereo Main Power Amp AA 45 94 59.72 TA-820A 6OW46OW OCL DC Pie-Main Stereo Amp AA 40 39 49.37 TA-10O0A 1 0QW Dynamic Class "A'Main Power Mono Amp AA 59.69 80.58 TA-1500 10OWx2 Class "A" DC Stereo Pre-Main Amp AAA 73.70 95.81 TA-2200 FET Super Class "A - DC Pre-Amp AAA 47.70 58.24 TA-2400A Electronic Echo & Reverberation Amp AAA* 116.80 TA-2500 HO Pre-Amp. w/10 band graphic equalizer * 90,80 TA-2800 HI-FET IC Pre-Amp. w/3 way tone control AA 48.90 63.57 TA-30O0 Stereo Simulator (mono TV /any mono source) AA 30.20 41.38 TA-36O0 300WHQ Hi-Fi Power Mono Amp AAA 79,00 103.00 POWER SUPPLIES KIT ASSMB rH-iOOA '.M>v;iv i J 'SaCLroa 1 "- J , f ;.>iQH iii ; =f- :j S69.S0 TH-355A 0-15V5A Regulated DC Power Supply A 14.55 20.76 TR-35SB O-30V3A Regulated DC Power Supply A 14.55 20.76 TH-503 O-50V 3A Regulated DC Power Supply AA 15-75 22.65 1NSIKIMKNTS KIT ASSMB. FKH! 3 12 Mulli- Functional Led D. P. M (w/ABS plastic case; AA ...S 34.50 S 43.00 ~ SM-48 4 1/2 Hi-Preclsion D.P.M.AAA , ..38.00 48.00 SM-48A 4 1/2 Hi- Prescision 0. P.M. w/ABS plastic case AAA 41.20 52.00 SM-49 3 1/2 Multi- Functional LCD O.P.M. (w/hoM function] AA 36.00 44.50 5M-100 150 MC Digital Frequency Counter AAA. ___._ 79.00 90.00 FC-1DOOA 1 GHz Freouencv Counter * 179 00 i rHQ n pb jflh .- a m n* w i w worn m ■■. CATALOG & INFORMATION (213) 888-8988 ORDER TOLL FREE 800-423-3483 IN CALIFORNIA 800-521 -MARK FAX (213) 888-6868 . Beginner A A Intermediate AAA Advanced * Fully Assembled SM-666 i x TR-355 ■ •*• r> o ("* SM-333 SM-222 MODS. Ty-2aa TY-25 TY-35 TY-36 TY-38 TY-41MKV TY-42 TY-43 TY-45 TY-47 SM-222 SM-328 SM-333 SM-666 MISCKIXANEOrS- DESCRIPTION 3 Channel Color Light Controller Stereo Loudspeaker Protector A. FM Wireless Microphone ™„, AC/DC Quartz Digital Clock A SaunaVTouch Control Switch A Kl ■ ASSMB. Inlared Remote Control Unit w/case AAA ; Bar/Dot Level Meter AA 3 1/2 Digital Panel Meter A , , 20 Steps Bar/Dot Audio Level Display AA .......... Superior Electronic Roulette AA. 7 Band HI-FI Graphic Equalizer AAA* 4 Channel Professional Color Light Controller*. . Audio/Video Surround Sound Processor AAA* Dynamic Noise Reduction A. . S 56.04 12.65 9.22 1B.O0 12.00 20.00 24,15 23.00 3645 19.46 26.80 .62.00 ,.26.00 S 74,50 18.88 35.00 3B.00 46.14 27.24 3880 150.00 83.00 34.00 METaL CABINETS with ai.hmim m I'asTJT MODEL H" I W I D- MATCHING LG-1273 3" 12" T TA 2800.TA-377A LG-16B4 4" 16" 6" TA-322I. TA-323A, TA-377A LG-1924 4" 19" 1114 TA-802. TA-820A. TA-15O0. TA-120MKII, TA-BOO. LG-1925 5" 19" 1114 TA-477, TA-800, TA-1500, TA-1000A LG-1983 2« 19" 8" TA-377A, TA-2800, TA-2200, TA-120MKJI PRICE J 20.16 24.64 30.00 33.00 26.50 MODEL DESCRIPTION MATCHING PRICE 001 S6VCT. 60VCT 6A TA8O0. TA-B02. TA-820A, TA.1OOOA.TA-15O0 t 26.00 002 72VCT3A TA-322,, TR-503, TA-323A, TA-400 2t.0O 003 60VCT6A TA-477 27 00 004 4BVCT6A TR-120 HK II 21.00 005 52VCT3A TR-355B 15.00 006 36VCT 5A TR-355A 14.50 0Q7 112VCT8A TA-3fiOO 42 00 MARK V ELECTRONICS, INC. -8019 E. Slauson Ave, Montebeilo. CA 90640 CIRCLE 93 ON FREE INFORMATION CARD c_ C Z m to CO o 81 CO o z o e UJ _l UJ 6 o < tr THE ELECTRONIC GOLDMINE ne Electronic UM> he «: 4 me sreSiS kiko^ of [p qjt riectodc Ub Mfcfifc *i ine Watt We hM over 130 Kits jnd i«tcsi tJKO uniw. bargain pnao., coirw- nrrtsn&jnwIiBacaiog^ll toqueil yntfrccrj today, rx beta p. order tnti bt placed on our Pt^ffed CutLamet nai -ng M \o ix vm rirsl Id reoftt aw aJaJogs utiem iney ai prrted. ^ MINI GEIGER COUNTER KIT A Everyone Irons ho* Ssonatinn, and useful Geioer Counters are, but mat price is usually JIM) a mxe 1 We've node a iremenctpus price tieaHlvough 1 Not only s an Geioer Carter Kit y\ C6430 me el the smalW. it's the mosl reasonatile^-^X jcg ge priced Geiger Counter available anyvvtere! This ullra-sensilive hit delects Alpha, Beta, Gamma and X-ray radia- tion and em .Is diets in pro- porticn lo die ■raniiy ot the radialinn Features sensitive al- pha wndowGM tube and IC circuit thai oper- ate tan standard 9V bat lery (rat included) Detects radiation torn radium dials on old wdcfm, lantern mantles, radioactive minerals, background radiation, etc Note not tor delecting, fladon Gas Sae of Board 3" x 1 9" Complete wlh all parts, PC board and instructions 20W +^0W STEREO AMP KTT ?* sejHTfc H&\'&m ar& cr one K Dead Ea^i i"T) na'Tfi om fe^ central «t PUB DJ m inOTJiiH 2QtafcfiMS FhTlik f, red LED Ti" inaavr am taw fowicri cSr- OiTlW Gfta: litres CooiCrjmgicrjrDtfQr :-: j-«j :>'.'■- use * h any mautT, capi!* o! ".jnci "] .i! Icasl 30 Wans QptrtfE; on IS/DC S« dI board 1 GT jt 225". Compi* win ill pats, PC Dcai-a art risrric^ C6442 $19.95 MINIMUM OflnER: S1OO0 pkis S3 00 slipping end handing -ECpl MC. VrSJ i"- J ' SEHO ORDERS TO: Tne EiKrionc GekWme PO Box S4M Sconsoatj. AZ 85261 PHONE ORDERS: (602) 451 74S4 CIRCLE 179 ON FREE INFORMATION CARD FREE CATALOG FAMOUS "FIRESTIK" BRAND CB ANTENNAS AND ACCESSORIES. QUALITY PRODUCTS FOR THE SERIOUS CB'er. SINCE 1962 FIRESTIK ANTENNA COMPANY 2614 EAST ADAMS PHOENIX. ARIZONA 85034 PROGRAMMABLE stepper motor drive & control for under $100, IBM PC/XT compatible, Com- modore 64, or olher with 25 pin parallel port. PCB, interface. & software. Send for detailed literature to: MASE, R.D. #2 Box 166. Mohrsville, PA 19541. DIGITIZER for IBM compatible PCs 640 by 4B0 resolution from VCR video camera $85.00 demon- stration disk $3.00. CODEWARE, Bon 3091, Nashua, NH 03061. COMMUNICATIONS. electronic equipment, sales, service, FCC licensed, free catalog, RAYS, POBox14862, Fort Worth, TX76117-0B62. FREE catalog. Interfaces for tBM compatibles. Dig- ital 10 and analog input. Control relays, motors, tights, measure temperature, voltage. JOHN BELL ENGINEERING, INC., 400 Oxford Way, Belmont, CA 94002. (415)592-8411. Quality Microwave TV Antennas lncLc55LABLE-l.9 !oz.7Griz. 4ucbGain l. I i-Channe! System Complete St "19.95 |12'Criannel System Complete $114,95 ■ Call or Wrile lor "FREE" Catalog Phillips-Tech Electronics P.O. Box 8533 • Scottsdale, A2 35252 E {602)947-7700 IK M bed" ill photic ordenii WARRANTY MmtrCard * Via • CfJQ'l Cimntiiv Pricing CABLE descramblers (Jerrold) from $40.00. Tocom VtP test chip. Fully activates unit. $50.00 Call (213) 867-0081. CABLE TV TB-3 (Tri-Bi) or SA-3 Quantity Prices 10 20 $48. $43 Each 50 Each 100 *p*59a 9ii5i Each Each Hours open 10:00 am to 4:00 pm Eastern time Minimum order 5 units 55.00 ea. Dealers wanted. We ship COD. King Wholesale 1-800-729-0036 Fax number 6173400053 "No one beats the King's prices!" DESC RAMBLERS One tree can make ^OOGjOOO matches. s One match can burn 3,OO0j0O0 trees. I# PRINTED circuit boards etched & drilled. Free deliv- ery. K & F ELECTRONICS, INC., 33041 Groesbeck, Fraser. Ml 43026. (313) 294-8720. PHOTO FACT folders, under #1400 $4.00. Others $6,00. Postpaid. LOEB, 414 Chestnut Lane. East Meadow, NY 11554. CABLE TV descramblers M35B. Top quality. Test- ed, guaranteed, vari-sync available. Dealers want- ed. §39.00. 1 (800) 648-4600. STOP the electronic thieves! Techniques, equip- ment, laws. Free information. SVS, 198 N, 2nd Street, Suite 6, Porterville. CA 93257. (209) 781-2834. ROBOTICS software, PC/MS DOS. Explore com- puter vision, sonar sensing. Free brochure. ROBOTS ETC, Box 122, Tempe. AZ 35280. IMPORTANT fads for cable box buyers. Don't make costly mistake when you buy. Fast shipment. Send $10.00 to; VESTOR ASSOCIATES, Suite 205, 25 Forest Street, Attleboro, MA 02703. CB RADIO OWNERS! We specialize in a wide variety ot technical information, parts and services for CB radios. 10-Meter and FM conversion kits, repair books, plans, high-performance accessories. Thousands of satisfied customers since 1976! Catalog $2. CBC INTERNATIONAL P.O. BOX 31500RE. PHOENIX. AZ 85046 SOFTWARE as low as $1.99. IBM. Macintosh, Amiga, Apple & C64/128. CALIFORNIA FREE- WARE, 1747 East Ave Q #C-1, Paimdale, CA 93550. Free Catalog. Call 1 (800) 359-2189. SOURCES wanted for exciting, quality, proven products of interest to readers of this magazine DLJ-A, 485 Fuhriman, Providence, Utah 84332. Free catalog. DESCRAMBLERS — for tree catalog contact CA- BLE CONNECTION, 1304 E. Chicago Street, Suite 301, Algonquin, IL 60102. (70S) 658-2365. SAMS photofacts from 1964 thru 1972. Sell all - make offer. (818) 353-4603. KAREN ROBERSON, Los Angeles, CA. COMPUTER-aided-living, a new detailed guide shows how to use your computer to control lights and appliances, pay bills, obtain free soft- ware, much more! Send 59.95 (ppd) to: DANIEL ENGINEERING, 36437 Spruce, Newark, CA 94560. CABLE TV "BOXES" Converters— Descramblers Remote Controls— Accessories * Guaranteed Best Prices ■ * 1 Year Warranty - CO D.s » * Immediate Shipping * * FREE CATALOG * Call or Write TRANS-WORLD CABLE CO. 1 2062 South west 1 1 7ih Court. Suite 1 26 Miami. Florida 33 IBS I 1.800442-9333 RADIO tubes, parts. Extensive listings. $1.00 (re- fundable). DIERS, 4276-E5 North 50th Street, Mil- waukee, Wl 53216-1313. SURGE protectors, for all types of electronic equip- ment, low prices, super protection! Free information. DATA STAR COMPUTER SERVICE, 305 Summit Trace Drive. Tucker, GA 30084. CORDLESS soldering iron! New technology, heats up in seconds. 5 year warranty. $19.95. Free shipping. AUTOCOMM, 4174A S. Parker, #117, Aurora, CO 80014. 82 REMOTE CONTROL KEYCHA1N Complete w/mtni-transmltter and +5 vdo RF receiver Fully assembled Including plans to build your own auto alarm Quantity discounts available Check, Visa or M/C Add $ 3 shipping VISITECT INC./Dapt. R (41S) 872-0128 PO BOX 5442, SO, SAM FRAN, , CA 940SO $24.95 PLANS AND KITS BUILD this five-digit panel meter and square-wave generator including an ohms, capacitance and fre- quency meter. Detailed instructions $2.50. BAG- NALL ELECTRONICS, 179 May, Fairfield, CT 06430. ___ MINIATURE FM transmitters! Tracking transmitters! Voice disguisers! Bug detectors! Phone Devices! More! Available in kits or assembled! Catalog $2.00: XANDI ELECTRONICS, BOK 25647, Dept. 60E, Tempe, AZ 85265-5647. CATALOG: hobby/broadcasting/HAM/CB: Cable TV, transmitters, amplifiers, surveillance devices, computers, more! PAN AXIS, Box 130-F6, Para- dise. CA 95967. Unlock the Mystery of the Automobile Computer! Build Your Own Diagnostic Scan Tool! The Key To Understanding the Modern Electronically Controlled Automobile Engine.., Access Stored ECM Cam. Read-Out Fault Codes. ^ Challenging HEW Electronic Assembly KIT — C PLANS-PARTS-ASSEMBIELVTESTED UNITS Call 1-800-535-3091 or write tor complete Information SIM Electro-Tech P.O. Box 34334 Blaine, MM 5S434 SURVEILLANCE transmitter kits are available to law enforcement agencies that operate on frequen- cies they prefer. Four models of each; telephone, room, combination telephone/room transmitters tune from 65 to 305 MHz. Send $1.00 (overseas airmail $2.00) for catalog. Included is Popular Communications book review of "Now Hear This! Electronics Eavesdropping Equipment Design" by Winston Arrington. Book contains 58 transmitter schematics SHEFFIELD ELECTRONICS, 7223 Stony Island Ave., Chicago, IL 60649-2806. INVESTIGATORS, experimenters — Quality plans Micro and restricted devices. Free catalog. Self ad- dressed stamped envelope required KELLEY SE- CURITY INC., Suite 90, 2531 Sawtelle Blvd., Los Angeles, CA 90064. CB Tricks II book. Power amplifier design and theo- ry, UHFCB tune ups. Send $19,95 MEDICINE MAN CB, PO BOX 37, Clarksville, AR 72B30. DETECTION — Surveillance, debugging, plans, kits, assembled devices. Latest high-tech catalog $5. DETECTION SYSTEMS, 2515 E. Thomas, #16-864F, Phoenix, AZ 85016. Computer Kits They're Fun. Easy to build, IBM Compatible. Educational, Powirful Willi Wholesale Prices, All Kits include a free Assembly Manual Free Software, One Yoor Warranty and 24 hour Phone Support Una Asv for our free Cat&log (516) 9B1-9473 ^^ General Technics ^^\ Quality Computer Syslems P.O. Box 2676 ig Available tofee Bonkonkoma. NY 1 1779 BUILD robot from outer space! Plans $11.95. de- tails free. ROBOT WORKS, Box 1979, Colorado Springs, CO 80901 REMOVE lead vocals from standard stereo rec- ords, CDs, tapes, FM broadcasts, so you can be the lead singer of your favorite band. Theory/schematic $6.95. PCB and parts also available. WEEDER TECHNOLOGIES, 14773 Lindsay, Mi. Orab, OH 45154. BARGAIN plan. Desk top computer stand. Easily built. Personal pride. Send $4.00, now... CREATE. PO Box 440062, Aurora, CO 80044. CABLE-TV BONANZA! •CALL FOR AVAILABILITY Name Address . State .City. . Zip. D Cashier's Check Acct # □ Money Order .Phone Number ( ) D COD D Visa Exp. Date ITEM 1 UNIT 10 OR MO HE HAMLIN MCC 1IOQO 36 CORDED HEMOTE CONVERTER. iCM (iHilyi 29 00 teoo i^',A -: .Mi- '.vir&lES^ converter ,:j.,r :*■;,' r,.,v 98 00 79 00 STAR GAIE 2000 SS 00 6900 ■JERROLD 100 COMBO 169 00 H900 JERROLO -:0O HAND REMOTE CONTROL n M i 5 ■::■ JERROlD A!it> COMBO '99 00 11900 J6RR0LD 450 HAND REMOTE CONTROL 29 00 1800 JERROLD SB-ADD-ON 99 00 63 00 ■ J E fl OL D Sfl - A D D - O N W 1 " H "' R 1 M O r> E- 10900 i' : 1:0 ■M-3SBCOMQO UNIT ■ .lr,„l|„:l ..rilyi ■ ■ 9 -'i: i=-> 00 SCIENTIFIC ATLANTA ADOON REPLACEMENT DESCRAM8LER 11900 0b 00 Quantity Item Output Channel Price Each TOTAL PRICE SUBTOTAL from shipping any cable descrambling unit to anyone residing in the state of California. Prices subject to change without notice. Shipping Add $3.00 per unit COD & Credit Cards — Add 5% PLEASE PRINT TOTAL O Mastercard Signature FOR OUR RECORDS: DECLARATION Of AUTHORIZED USE — i. the undersigned, do hereby declare under penalty of perjury that all products purchased, now and m the future, will only be used on cable TV systems with proper authorization from local officials or cable company officials in accordance with all applicable lederal and Slate laws FEDERAL AND VARIOUS STATE LAWS PROVIDE FOR SUBSTANTIAL CRIMINAL AND CIVIL PENALTIES FOR UNAUTHORIZED USE. Dated:. .Signed:. s 2 s I I s \ Pacific Cable Company, Inc. 7325V2 RESEDA BLVD., DEPT. R-6 • RESEDA, CA 91335 {818)716-5914 ■ No Collect Calls • (818)716-5140 IMPORTANT: WHEN CALLING FOR INFORMATION Please have the make and model # of the equipment used in your area. Thank You c z m ID (O O 83 « o z o en r- O LLI O Q < njMncD(Dn3M rou» /.C. SOURCE COLLIMATOR PEN (INFRA-RED) A tow power collimator pen containing a MOVPE grown sain guided GaAIAs laser, this collimator pen delivers a maximum CW output power nl 2.5 rn W at 25* These co Hi mate c- laser sources a re designed tor industrial applications such as data retrieval, telemetry, alignment, etc. Die non-hermetic stainless steel encapsulation ol the pen Is specifically designed for easy align merit in an optical read or write system, and consists ol a lens and a laser device. TTie tens system colli males the diverging laser light. The wavefront qua lily is diffraction limited. The housing Is circular and precision manufactured with a diameter of 1 1 .0 mm and an accuracy between + and - 11u m. OUR PRICE: $39.99 ■ QUALITY COMPONENTS .LOW PfllCESSINCf 1983- LASER DIODE (INFRA-RED) Designed lor general industrial low power applications such as reading optical discs, optical memories, barcode scanners, se- curity systems, alignment, etc. The gain guided laser is con- structed on an n-type gallium a rsenide substrate wit h a Metal r - ganic Vapor Phase Epitaxial proc- ess I MOVPE). The device is mounted in a hermetic SOT148D encapsula- tion, {diameter 9.0 mm) The SB1Q53 is standard equ i pped with a m onilu r d iode , iso- lated from the case and optically coupled to the rear-em ittinj fascet of the laser. This fast- responding moni- tor diode can he used as a sensor to control the laser optical output level. L IS T PRI C E : t38 .00 OUR PRICE: $9.99 • WE CARRY A FULL LINE OF COMPONENTS! • EPROMS STOCK* 17M 2TW 37W 2716 3718-1 TWM7K 27C16 37K :t,;?a : zraA 27J2A-* TUSKS XTCS 1714 ZTfrU WHS MSCRIPTBH 34 256 X 4 lit* U 1024KB 45Gftt 24 loa^s 4Un M rtf-i'J-. 3 ■iSOmr.Hvl 34 :■.■■■! '.■■:■■ 3E0'-.i.:s>i 24 2WJ MAINTAIN/REPAIR PRINTERS. yiejiks tnmii-mmiis r*Amms ruts am caHPAnmn TKAmme MMMMWERSOO (CIlOH-PKfEO M8ES) IttVlttS SICUTS OFPfllMIERBEPAIR. wmnraunwiRMt MECHANICAL ABILirr WE CAN SHOW YOU HQWTQHEPAIHUPTO ^ 35%Of ALL PBINTEftS STMT EARNING EXIM CASH IN DATS! • HIIBE UNUfPED EMMET! • lERIOUS LICK D( TOXIN CD TECHNICIAN* (WEB 37 MILLION PC'S IN USE . . APPROXIMATELY !SS HAVE A PRrNrER ATTACHED . Mf mjUMI rr OF PF I KT E B S B E »« DOWNS A R E DUE 10 SIM PLE MECHANICAL OB ELECTA D -MECHANICAL FAILURE OB WBITE ID: VIEJO PLtNLICATIDKS 3S10 IVILSHIRE BL ' 310 OEFT1H I. A. CA 9001(1 FREE INFO CALL1-8O0-537-O589 BUSINESS OPPORTUNITIES EASY work! Excellent pay! Assemble products at home. Call (or information. (504) 641-8003 Ext. 5192. MAKE $50/hr working evenings or weekends in your own electronics business. Send for free facts. INDUSTRY, Box 531, Bronx, NY 10461. YOUR own radio station! AM, FM, TV, cable. Li- censed/unlicensed. BROADCASTING, Box 130- F6. Paradise, CA 95967. INVENTORS: We submit ideas to industry. Find out what we can do for you. Call 1 (800) 288-IDEA. LET the government finance your small business. Grants/loans to $500,000. Free recorded message: (707) 449-8600, (KS1). WHOLESALE PRINTER CAFJLES.IBM-PC 2 pcs/$1 2 (6ft). 2 pcs/$14 (1 Oft). All 25P included. (718) 628-4117. Send M.O. to C&D INTERNATIONAL P. O. Box 4333Z. LLC., NY 11104, CABLE TV. CONVERTERS WHY PAY A HIGH MONTHLY FEE? All Jerrold, Oak, Hamlin, Zenith, Scientific Atlanta, Magnavox and all specialized cable equipment available for shipment within 24 hours. Forfast service MCv VISA orC.O.D. telephone orders accepted (800) 648-3030 60 Day Guarantee (Quantity Discounts) 8 A.M. to 5 P.M. C.S.T. CLOSED WEEK- ENDS. Send self-addressEKl Stamped enve- lope (60c postage) for Catalog. MAKE $75,000 to $250,000 yearly or more fixing IBM color monitors (and most brands). No invest- ment. Start doing it from your home. (A telephone required.) information, USA, Canada $1,00 cash. US funds, other countries $8.00 RANDALL DIS- PLAY 9ox 2168-R Van Nuys, CA 91404, USA. LEARN to clean/repair Fax machines. Huge new market! Earn $85/hour. No experience necessary. Free details call 1 (800) 537-0589 or write to: VIEJO PUBLICATIONS 3540 Wilshire B ! lvd. #310 Oept. FX2O0 LA CA. 90010 GFU1- Mm GRAVITY GENEMOR S10J0O m in- 40 WATT BURNING CUTTING LASER $2000 = *RUB4- HI POWER PUIS EC DRILLING LASER $2000 «pBTC5- 1 MILLION VOLT TESLA COIL .. .S20.OO EEHCP1- HI VELOCITY COIL GUN S1500 £ = LLS1- LASffl LIGHT SHOW 3 METHODS S26tM C^JEHI- ELECTRONIC HYPNOTISM TECHNIQUES 58.00 ZEML1- LOWER PW/EHED COIL GUN LAUNCHER sa.00 3JL3- JACOB LADDEH 3 MODELS . . $10.00 SD5- SEE IN THE DARK $10.00 O- LEVI - LEVITATION DEVICE . . $10.00 FMY1K - 3 MILE FM VOICE TRANSMITTER $34.50 PFS1K - HAND CONTROLLED PLASMA FIRE SABER $4950 NIG7K - HI FLUX NEGATIVE ION GENERATOR . . . $3450 PG5K- PLASMA LIGHTNING GLOBE $4950 LHCIK- VISIBLE SIMULATED 3 COLOR LASER S4450 H0D1 K - HOMINEVTHACKING BEEPER TRANSMITTER $44 50 LGLI6K — 2 5 MW HAND-H E LD VISIBLE LASER GUN $24950 HTC3K- 250000 VOLT TABLE TOP TESLA COIL . . $24950 I0G2K— ION FW GUN . project energy without wires .. S129S5 TKE1K- TELEKINETIC ENHANCER/ELECTRIC MAN $7950 VWPM7K - 3 MILE AUTO TELEPHONE TRANSMITTER $4950 si 1-1 AS5E M B LE D I N Oil R LAB S 2 LISTM - INFINTTY XMTR Listen in via phone tries ... . $19950 _J IPG70- INVISIBLEPA1N FIELD BLASTWAVEGENERAiOR$74.5D CO ITM1D — 1 LTO,O0O VOLT INT1MILVUTJR UP "JO 20 ' . . S9950 S 7*130 - AUTOMATIC TELEPHONE RECORDING DEVfCE . $2450 Ijj PSP40 - PHAS0R SONIC BLAST WAVE PISTOL $99.50 ^JONEIB- ALL NEW 26 "VIVID COLORED NEON STICK . $7450 CO LBU20- 5T0 1MWV1SIBLE REOHeNe LASERGUN .$199.50 "S BLS10- 100C0WAH BLASTER OEFENSE WAND $89.50 EASY ORDERING PROCEDURE ■ TOLL FREE 1-800-221-1705 or 24 HHS ON 1-603-673-473OOT FAX IT TO 1-6TJ3-672-5406 VISA. MC, CHECK, MOINUSFUNDS. INCLUDE 10% SHIPPING. ORDERS $100.00 i UPONLY ADD S10B0, CATALOG SlJOOOfi FREEWITHOflDER, INFORMATION UNLIMITED P.O. BOX 716, DEFT. R2. AMHERST, NH 03031 VMJ BOEOA Z90A CPU 1 75 ZBOEi CPU 3 7b 780ACTC 1 OS 23QADART5 25 7BQ-A DM A 5i SO HOA flO 1 B5 «PA r, - r MO ZOOB S10 005 12C43 2.75 AMD2SCI 4 00 eso'j 3JB 5522 j.so 6W0 1-35 em *.&o 8801L BOO bjh TRANSISTOR SPECIAL )-fiQ l.Tb B.DO 1500 3.25 3.75 0821 U845 SM54 h5 15450 68QTSHJ (3 05 B88B1 'r'. EO FJI55 7 B202 6203 B712 9.214 822* flJIS 62/315 6.233 msoe B251-A S253 R54 B255A 5 1 !Fj fi25T 3.443 82&o fiZ?3A 6275 B27S-3 2.2b s.ao 6-50 J-.95 6 75 2.40 1.7& 3 95 3.40 1 1» 236 a jo 82B8 * 1t\ TH3W!?HLBB5 flflMOLf tt&fi :■:. LC?i »lfl )1DIA< Jill A 711T-1 ?1 1 C-l 211 M 714 7-1 324? T-MSJ40S MKL4977-? TMS*050hrL 1 VS. MK40SB -tl 1 JS 410S3 1.» 4T75S-10 CAI.L -1."^-'. CALL 4164-15 CAuL 400010 8 CALL 414B4-10 CALL M.K4B02 ZH1D4-4 61 16-3 02IHLP-15 4.W GOQ M5 KdO .■ r ,ti S11S-13 2sa REEISTERS MM 1403 !.71 -r/MHOJ 1 75 MA114U 1.75 MWSOia 2. 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HC^SOO fiO WATTS S3^.9S 1 1... .■ 15FM li.M..,i: ■one I6l6a 1BHBA 20HUA TANTALU M CAPACITORS DBUF 35V 1UF 20v 1 2UF 20V J JU' 20V 4r.7UF 20V SSUF 20V 10UF 30V S.'SI 00 94100 ■.-■Si 00 L.31 DO 5i'51 00 4rtSl.OO 4.51 00 4.S1 00 5 ■•■>■> 15UF 1DV -•-■•J- ■<:•,:■ 30UF0V 33UF 16V 47UF 30V HJUF30V \!Xl\:t 1EV 310OF 10V 3 Si 00 S 3D 5,81 .00 S 30 8 85 Si 00 81.10 81 tl, DISC CAPACITORS IUF1&V lOlSl DO lCO..SflDD Q1LIF35V 16rSl.O0 IDO'85 00 IN414E lUtHV IB-LOS LAS3SU 7BL05v 13 70WD6. 1 7 on L>*305 jook: LM317T. 320T 5,12,16 a REGULATORS 5505 S 30 5 40 333K lLAl4Q4r L.M337 34QT- 5.6.8.1 J, !-..■;■.. 74V 723 L1411 |H BtvnttP FPIOOPnoHiTrBt*^ Hid LEOt ,7"' ftntn^OrMTTi, or AnobCD Li LGU'l nm-Giwn BidoIjf LED . . Hh] V*HOVr BlQQlu LEQ MLEJO021H L£n UHL>14fl PnotDlfru. XtOFt IL-G Ciiio It-j-jid. , on McT 3 4N45 OpiQ D3j|..-. ■Sj 5V QK\ IJV &PST COPROCESSORS 8087'? S11E.M SflflT-3 ....... ^ . $ d&.[>q 30387-16 S3D0-00 PULL WAVE BRIDGE PFW 3A 6A 25* 100 1 40 200 90 I 30 220 400 ISO 3.95 330 600 1 30 1 00 4 40 D.P SWITCHES CT5 30E 4 4 C...|.„„ CTS306 J rPMItiOH CT5 200 8 SPtMilrtii CIS 200 tQ tQPcninwi ■ SILICON POWEF RECTIFIERS PRV IA 3A I3A 50A 1354 240A 100 05 14 35 90 QOO 6 50 20D 00 17 50 1 30 800 11,50 400 og 35 65 1 50 10M 13.10 600 11 30 60 3 00 1100 lC 00 800 13 .-■'.. 1 .c 7 ■--. if. .-■■ ;-, ■:■■.,. 1D0Q 70 45 1.25 3 00 20 00 26 00 MULTl TURN TRIM POTS MOmM 100 SJM'-.l IOOO OHM 6K, tOK ?0t 50 f- IOOK 3/S2 00 POSTAGE RATES ADO 10% FOR ORDERS UNDER 3-25,00 ADO 5% FOR ORDERS BETWEEN 425.00 AND $100-00 ADD 3* FOR ORDERS ABOVE SlDD.OO TERhrTS- FQ6 CAMHHirKi6. MASS S^ND CMEC- OH MONt f Ofl DEH MINIMUM TELEPHONE, CD □.PURCHASE ORDER OR CHARGE 52000 MINIMUM MAIL ORDER S5.00 SOLID STATE SALES P.O. BOX74D - SOMERVILLE. MASS. 02143 TEL. (617) 547-7053 FAX: (617) 492-8845 SENDS 75 FDFI OUR CATALOG FE ATUHIMI TRANSISTORS A FttCTIFItRS 145 HAMrSHfftt ST.. CAMBHlDrJit, MASS 02l3fi WE SHIP OVER 95% OF OUR ORDERS WITHIN 24 HOUFISOF RECEIPT CIRCLE 74 ON FREE INFORMATION CARD C Z m (D O 85 I CABLE TV CONVERTERS & EQUIPMENT ^ ONE 10+ UNIT units PANASONIC WIRELESS CONVERTER 65.00. . . 69.00 JERROLD 400 COMBO VW REMOTE (DRX30IC) 134.00... 95.00 JERROLO 400 OR 450 REMOTE HAND UNIT 24.00... 15.00 JERROLD JRX 3DIC 84.00. . . 65.00 JERROLD SB ADD ON 74.00... 55.00 JERROLD SB ADD ON WITH TRI-BI 95,00... 70.00 OAK M-35 COMBO 79.00. . . 50.00 OAK MINICODE (N-12) 84.00 59.00 HAMLIN MLD 1200 64.00... 45.00 SCIENTIFIC ATLANTA SA-3 ADD ON 109.00. . . 76.00 INTERFERENCE FILTER (CHANNEL 3 OR 6) 24.00... 14.00 NEW SCIENTIFIC ATLANTA COMBO 275.00. . 215.00 PIONEER DESCRAMBLER 250.00 200.00 TOCOM VIP 200.00. . 175.00 ZENITH FLASHING 175.00.. 150.00 ZENITH SSAVI 125.00... 90.00 EAGLE PD-3 95.00... 75.00 VIDEO-LINK Enterprises, Inc. 520 GLENBR00K RD., SUITE 202 STA MFORD, CT 06906 ORDERS: 1-300-622-9022 CATALOG & INFO: 203-975-7543 MONDAY - FRIDAY 10 AM — 5:30 PM, E.S.T. IMPORTANT: Have make and model # of the equipment used in your area. QTY ITEM OUTPUT CHANNEL NO CONNECTICUT SALES. It is nol the intent of VIDEO- LINK 10 defraud any pay television operator and we will not assist any company or individual in doing so. PLEASE PRINT: a CASHIER'S CHECK NAME PRICE EACH SUBTOT. Shipping W/llnil COD: Add 5% TOTAL TOTAL PRICE a m.o. a c.o.a ADDRESS CITY/STATEVZ1P. PHONE SIGNATURE WAIVER. Since I, the undersigned, fully understand lhal the ownership of a cable decoder does not give the owner of the decoder Ihe right to decode or view premium cable channels without proper authorization from their local cable company, hereby declare under penally of perjury that all products purchased, at any time, will only be used on cable TV systems with proper authorizalion from local officials or cable company officers in accordance with all applicable federal and state laws. Federal and various stale laws provide lor substantial criminal and civil penal lies for unauthorized use. Dated: Signed: CIRCLE 64 ON FREE INFORMATION CARD DIGITAL V.O.M./D.P.M. SALES— SERVICE— PARTS FLUKE-BECKMAN-S1MPSON-ETC. U.S. MADE ONLY. QUOTATION PRIOR TO WORK. FAST SERVICE, 90 DAY WARRANTY. STANDARDS TRACEABLE TO NBS. SINCE 1948. CALIBRATION CERTIFICATE AVAILABLE. INDUSTRIAL INSTRUMENT WKS. INC. S74E SALMEN, HARAHAN, LA 70123 504.733-8355 EARN $1000's extra as a part-time computer dealer. Where to buy products at big discounts. Who to sell to. Financing without cash. Obtaining free software. Exclusive dealer trade shows. Step-by- step check list. Industry inside knowledge. Written by industry pioneer. Order now, only $24.95 plus $4.00 shipping/handling, CA residents add $1.81 sales tax. CORNERSTONE PUBLICATIONS, Dept BB, PO Box 5151. San Jose. CA 95150. Allow 2-4 weeks. EASY! Moneymaking one man CRT rebuilding machinery. $6,500,00 - $11,900.00. 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(New York residents add applicable state and local sales tax). THE MAGIC COURSE, 500-B BiCounty Boulevard, Farmingdale, NY 11735. BE A RECORDING ENGINEER; Train at home for high-paying — Exciting careers. FREE information. AUDIO INSTITUTE 2174 Union St. Suite 22K, San Francisco, CA 94123 FREE SUBSCRIPTIONS to over 200 major com- puter and business magazines — Guaranteed. Write for free information: SEABIRD 4N Militia Drive, Lexington, MA 02173. COMPLETE Digital Training course. Comprehen- sive overview of digital electronics. Super handy desktop reference! Hundreds of pages/illustrations. Free newsletter with order. Send $10.00 to VIEJO PUBLICATIONS 3540 Wilshire Bl. #310 Dept. DG100 LA CA 90010 or call 1 (800) 537-0589. Be a TV/VCR Repair Specialist Now you can train at home in spare time (or a money-making career as a TV.'VCfl Repair Specialist. No previous experi- ence necessary. 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THIS IS A BOLDFACE EXPANDED AD with a tint background. . If you like this format, request it. Your cost Is $6.25 per word. 86 INVENTORS INVENTORS! Can you patent and profit from your idea? Call AMERICAN INVENTORS CORPORA- TION lor free information. Over a decade of service 1 (800) 338-5656. In Massachusetts or Canada call (4f3) 568-3753. BEST BY MAIL Rates: Write National, Box 5 Sarasota, FL 34230 OF INTEHEST TO ALL GOVERNMENT SEIZED VEHICLES Low a$ SIM! Amazing recorded message reveals details! (708)70 5-2 324. INSTANT POSTCARDS!! SAMPLE, send $25 stamp BOX 171 (RE), Ashland, OR 975m BUSINESS OPPORTUNITIES EARN EXTRA INCOME mailing brochures for national companies! No experience needed! Mall Si: Finance Publications, Box 167B(RE|, Arvada, CO 80001. I MAKE 82,000 WEEK Recycling Gold I Easy home business! Free booklet! 1(900)2-46-2323 (S2fm In). SJ50 WEEKLY! IMMEDIATE home income! Photograph data lorms! Experience unnecessary. Free details! PHILLIPS(RE), Garrett, PA 15542-0051. FREE CATALOG! 1-800-648-7938 For all information 1-702-362-9026 JERROLD HAMLIN OAK ETC. CABLE TV DESCRAMBLERS • Compare our low Low Retail Prices! • Guaranteed Prices & Warranties! • Orders Shipped Immediately! REPUBLIC CABLE PRODUCTS INC. 4080 Paradise Rti ■■• IS Depl. HE-MI ' Las Vegas, NV 89109 — «- LOGIC ANALYZER continued from page 21 different trigger words. Up to three triggers can be OR-ed together on each level. It is possible to enter some rather complex triggering schemes, with conditional branches, loops, and the like. Trace recording can be turned on and off on any level so that only the data that is of interest— not, for example, a1,000-count loop* — is stored. The PA480 48-bit x 4096-word, 25 MHz logic analyzer board costs $1595. Either a general purpose pod or a microprocessor disassembly pod is required for operation. They run from $495 to $695. Because we have limited space in which to describe the analyzer, we have only scratched the surface of its capabilities and features. We were very impressed with its opera- tion, and think it deserves a serious look from anyone contemplating the purchase of a logic analyzer — and a serious look from some of the competition as well. R-E CONSOLIDATED E L E C THE ULTIMATE ELECTRONICS CATALOG Order your 260 page catalog and price Uit with over 14,000 moiwy laving electronic parti and equipment! Send 13.00 in e check or money order, or cell 1-80(^643^(568 today end me your Uaitersard or Vita. Consolidated Electronic!, Incorporated 706 Ws tervliet Ave , Dayton, Ohio 45420-2599 Name Addreai_ City _State_ _Zip_ CIRCLE 70 ON FREE INFORMATION CARD Parts EMINENCE JlNr ®***** pc*** 1-800-338-0531 ^ p,oruEER 3-WAY 100W CROSSOVER 12 dzVoctave rollofl. 800Hz, 5000Hz crossover points. 8 ohm, 100 watts RMS. t& .v-260-210 $12.50 (1-9) $9.95 (10-up) SPEAKER CONTROL PANEL Panel with SO wait L-pada for tweeter and inidrange and biull -in LED power meter, 5 w x 2 1/2' 100 watt version available $14.50 #260-235 (1-5) $12.90 (6-up) 12 POLY WOOFER Super duty, 40 oz. magneL 100 watts RMS, 145 watts max A and B ohm compat- ible (6 ohm}. V voice coil. fa=tflSlfa.QTS=.lGe i VAS=10.8cuft, Response: £5-1500 Hi. Net weight: 9 lbs. Pioneer HA3CGU40-51D #290-125 *?££* < $34.50 (4-up) 15" WOOFER Original Sanyo woofs r. Paper cone with vented dust cap and treated clolh surround. 12 oz, magnet, 60 watts RMS, 05 watts max. 8 ohm. Resonance: 26 Hz. Response: 25- 2,500 Hz. #291-t55 $23" (1-5) $21 90 (6-up) PIONEER HORN TWEETER Mylar dome. 2.93 oz. barium lerrite magnet, 9 ohm. Response: 1900- 20000 Hz. 35WRMS. SOW max 6; = 2000Bz, SPL = 106 d£. Pioneer #AHE60-51F I #210-050 W" 9) $5.90 (10-up) //>- Parts fcxpress 14} £. Fast EL, Diylon. Ohio 4540G loci]: 1413-323-0173 FAX: 5J3-222-4eU ' .5 day irwrtw b«± cruaracw '(15W mnirijm ofdi» ■We*Gcap! Mjataxarf, VL^DurxrrcrardCO.D. cidras "Si h<*=rs.h[wa •Shipping charge - UPS chart rmUt 'S3.CO (53.00 miflimum chuffs) " Horns B:30 am- 6 CO pm EST. Monday - Friday *Mad order cunomtTL plaua Gall for shipping wtjmitei on orde-ra exccecLng 3 lbs. 12" SUB WOOFER Dual voice coil sub woofer. 30 oe- magnet. T voice coils. 300 watts RMS, 14-9 watts max. (s = 2S Hz. 6 ohm (4 and 8 ohm compatible). 5PL-B9dB 1W/1M. Response: 25-700 Hz. QTS=.31, VAS= 10-3 cu- ft.. Pioneer * .= 3QGU30-55D. Net weight: 6 lbs. #290-145 ff.!) 80 $36.80 (4-up) 15 THRUSTER WOOFER Thruster by Eminence- Made in USA. Poly foam surround, 58 oz. magnet. 2-lrT, 2 layer voice coil 150 watte RMS. 210 watts max. 4 ohm. [a = £3.5 Hz,QTS = .33 f VAS-119 cult. SPL = 94,8 dB 1W/ 1M. Net weight: 15 lbs. $43.50 $39.80 (1-3) (4-up) #290-180 GRILL FRAME KIT With this lot you can make speaker gnli frames up to 3Q*x40". Et inchidea 4 corner pieces, 2 T* brackets, and 7 frame bars. Oriil mounting kit included. #260-333 $8.50 (1-9) $7.80 (10-up) 18 EMINENCE WOOFER MADE IN USA 100 oz. magnet, 3" voice coil. 250 watte RMS. 350 watts max. 8 ohm, 30 Hz resonant frequency. 22- £700 Hz response. Efficiency; 93 dB IW/lftl Paper cone treated accordian surround. Net weight 39 lbs. #290-200 $98.90 (1-3) $89.50 (4-up) TITANIUM COMPOSITE TWEETER Lpouynw dcinttocoinbnUH advantage*, of boo hud and sen dwrtc UrfuiclQ^Ba. S ohm Fkto Qu*i cooled vojes coil is ~ S200 Kx. SFL=ttJdfl 1W/IM. SOwansRMS. 70 WUU mas . 4" round Pofydax pan *DTWKCT523 $23.50 #210-047 (1-9) w $24.80 (10-up) CIRCLE 56 ON FREE INFORMATION CARD 87 DESCRAMBLERS 'The Empire Strikes Back" 'We Cut Prices To The Bare Essentials" There Is NO Competition ANYWHERE ! JERROLD™ TB-3 SCIENTIFIC ATLANTA HAMLIN MLD1200 OAK M35B W/VARI-SYNC INTELESTAR CONVERTERS DF-3/2 RLTERS FULL WARRANTY 10%UNDER ANYONESI Quoted or Advertised Prices. ..Even The Wh j*5? te For ?,eaTca,,' n, ° (402)331-3228 Krigs! SALES REGULATED BY FEDERALS STATE UW ANYONE IMPLYING THEFT OF SERVICES WILL BE DENIED PURCHASE ^ ii-ii-- :..5.-...-i- fa ' •■■ : .. 5 ' Id ■ ' -Tia HE €6137 CIRCLE 196 ON FREE INFORMATION CARD KIT REPORT continued from page 57 coded from standard stereo TV broadcasts. However, some network TV shows are beginning to incorpo- rate surround techniques as well. Surround sound can even show up where you'd least expect it. Our local public television station supplied the surround channel with music as they conducted a pledge drive in the front speakers. The AD-2550 is priced at $199. A pair of surround-channel speakers are also available from Heath for $49.95. In our opinion, the pro- cessor provides beffer-than-movie- theater conditions. We get full con- trol over the sound, and in our living room, the popcorn is fresh\ r-e i:iiHiiiiiiAiiiiniuiii:>'n Circu* added to your phone always silences 1st ring. When you 501*5 secrel sequence tf "stent rings' - your phone answers flsetf allowing you lo fcsten in on room wiiile still art the hoc*.' You are not delected 1 Works like a normal [tone all olhef imes. Free hard to find TCM : 5CS- ring detector chip included with step ey step instnclions. Send $13.95 Id: LASER BOUNCE, INC, 2020 Pennsylvania Ave. NW Suite JM2 Washington. D,C. 20CO6 S- g z o X. H O Q < DC 86 If You Are Buying Any of The Following Panasonic® Products Elsewhere, You Are Paying Too Much! Period. * Series * Series * Series * Series * Series * Series * Series * Series * Series ECQ-E Metallized Polyester Capacitors * Series ECQ-P(F) Precision Polypropylene Capacitors * Series X-Y Interference Suppressor AC Capacitors * Series ECE-Z Low Impedance Aluminum Electrolytic Caps. * Series TSW Large Aluminum Electrolytic Capacitors * Series EVN-KO & EVN-K4 Carbon Trim-Pots. * Series EVM-31G & EVN-36C Dust-Proof Cermet Trim-Pots * Series EVM-QO & EVM-Q1 Hermetically Sealed Trim Pots * Series EXBF 2% SLP Resistor Networks ECQ-M Polyester & Foil Capacitors ECQ-V Metallized Stacked Film Capacitors ECE-K Sub-Miniature Aluminum Electrolytic Capacitors ECE-LS Miniature Aluminum Electrolytic Capacitors ECS-EF Dipped Solid Tantalum Capacitors EVM-MOF & EVM-M1F Industrial Cermet Trim-Pots EVM-SOG Hermetically Sealed Trimmer Potentiometers EVM-C7G Rectangular 15-Turn Trimmer Potentiometers 12 Months Saving Guarantee We will refund the first year Membership Fee of any member who has purchased $300 or mora worth of products from Electronic Buyers Club and has not saved an amount greater than the first year Membership Fee, if buying the same items elsewhere. And these are only 1603 of the more than 10,000 Items that we stock ond offer to our Members at super low prices. In fact after buying Just a few hundred of the above items from Electronic Buyers Club, you will recover the S35.00 Annual Membership Fee while your saving continues on for the rest of the year. Become a Member today and start paying Less. 30 Days Money Back Guarantee We will refund the full Membership Fee of any new member of Electronic Buyers Club who within 30 Days after receiving the Membership Binder, returns the Binder to EBC and asks for the cancellation of Membership. (glecfcronic [guyers (£lub A Division of IrtenuEionil Component* Corponiion 1803 N.W. Lincoln Way • Toledo, OR 97391 PHONE (All 50 States & Canada): 1-800-325-0101 FAX: (503) 336-4400 • Hours: 6:00 AM - 6:00 PM PST MasterCard CIRCLE 184 ON FREE INFORMATION CARD R An HELP R REmTtR • A friend gave NORMAN JUST a Knight color pattern/generator, model KG-685, but the owner's manual, parts list, and schematic were missing. The unit needs some replacement parts and re- pairs. If you have any informa- tion on that model, please send it to 7926 Nocturne Drive, Louisville, KY 40272. • After subscribing to Radio- Electronics for 25 years, CHARLES BROCKMAN is in need of the schematic for a Teledyne model RA-618 AM/FM receiver. If you have one, or can advise him of a source, please write to him at 2602 Woodlawn, Ennis, TX 75119. • BRUCE KLIMISCH has an RF generator, El CO model number 369. It's in kit form, with no as- sembly information. He'd like to receive an instruction manual at 808 MacBeth Circle, Lakeville, MN 55044. Try the Electronics bulletin board system (RE-BBS) 516-293-2283 The more you use it the more useful it becomes. We support 300 and 1200 baud operation. Parameters: 8N1 (8 data bits, no parity, 1 stop bit) or 7E1 {7 data bits, even parity, 1 stop bit). Add yourself to our user files to increase your access. Communicate with other R-E readers. Leave your comments on R-E with the SYSOP. RE-BBS 516-293-2283 BUY SMART Here's a sample of just a few great money- saving deals. Be smart, order today. TURBO XT MOTHERBOARD ,tjf£ [IZ Mhz.| Fully BOSS temp Ml 01 e! ' * Speed SercctaHc * Eight Expansion Slots * Memory expandable to 1 640K :ok installed] BBplD Mfr: AUt Documentation included. ICustorner Upgrades) Item «2S 674 Special! $75.00 9" HI-RESOLUTION TTL MONITOR I OPEN FRAME GREEN PHOSPHOR Schematic induded- Mfr — Ban IBOCI 90 l[cm#T719a NOT- J 19.95 ■V. i SUM-LINE — EXTERNAL DISK DRIVE CHASSIS pile Drives not Included! Can ,m accommodated f 1 luif-iuigm floppy rirhrei, 5-1/4'. or 3-t/T In 5-1/*' frame. Inpue 1 1 5W30VAC 50/Wtu. Orfg. designed tor Burroughs computer. Dtm.: l|.3/4'Lx9-lr4'Hx5-l/2-rj. Item 82*7112 rfe — $59.50 1O0%PC/XT Compatible? 16-Bit 8088-10 Turbo Mlcroprocciior WHh 12" Monochrome Monitor- Item JT27T90 — NEW — $399.00 With 12" Color Monitor... Item #27191 — NEW — $499.00 " Eur ii" ?. I 4.7 7W.\M Of I MhZ ft 'fi+ 1 wall state] ■ Speed iVrrltcrtabte by software, keyboard orJuTipers ■ includes vW« luppon tot Hercules & CGA Color * One S-l/4'Roppy Drive ■ S087 coprwKMr Socket ■ One Serial L One Parallef Port ■Ckxk CaiencieV with &anery tacit up American Design Components 81 5 Fairview Ave. Fair view, NJ 07022 MOKWM • 84*cy Keyboard • TWO S-Bit Expansion Slots Alio Available: 20Mb HARD DISK on a CARD... item #77192 — NEW — $299.00 With our free catalog you'll get hundreds of sensational bargains to choose from. i So — isn't your order in order? f *8* y&Jl '**„ m w V I) ZOMfa HARD DISK DRIVES HALF HEIGHT ST72S. XTVVT CornparBle. Item B26533 HFE - $ r 79.00 FULL HEIGHT AT Compatible. 3 W cylinder; 9 head. Item SXMU RFE-S.59.95 5 V«" FLOPPY DISK DRIVES HALF HEIGHT i60H- DS/DD; 48 TO; 80 tract J Terutd Good! Item #247*3 $69.95 FULL HEIGHT dsttjo; 48 m: 40 tract Tfcsted G««d! ' item ntu $69.95 orany2for $120.00 E SUPPRESSOR ftotect you eotxpmerx from i | oatnaqing power surges. : I fiACorttecirLiapptoveci I ■ ISA. maximum load ■ Lighted Q«/CFF switch ■ Full 34ine EMWTF protection ■ 6 II. 1 4AWG grounder; power cord l[cmi;il3S NEW- $12.95 DIGITAL MULTIMETER . 3-1/2 Digit LCD Display features: DC/AC volts to I00OV * 1st Oast Accuracy |DC Volts + DC/AC Amps to 1 Ct*. * Continuity Beeper) ■ Diode test * Resistance to 20 Meg. rneiurjes: Test tead setvV batteiyand t Instruction manual. Item #2*59* NEW— $39.95 115 VAC MUFFIN- TYPE FANS Super quiet — Can be in lulled just about anywhere, for cooling or exhaust 5 METAL BLADES NEW- Item #18*4 $9.95 RFE - Item #SJ4S $5.95 4-1 l/l f SQ. x I-r/2* deep COMPUTER CARRYING CASE ON WHEELS Fits: IBM PSZ, MM Plus, Mac SK, * Hf-30 Opens front & top. or folds down flat for easy Coadino or unloading. Set of 4 removable casters. Fully padded Gordura nylon case: 4 large Interior pockets for all your accessor- ies; exterior keyboard pouch jfits extended keyboards]. Dim.: IS-Hx I4"WX IC.rO ■zi»9 new — $39.95 (800) 776-3700 American Design Components J I 815 Fairview Ave., RO. Box 220. Fairview, MJ 07022 I Thousands mora Itemi In our FREE CATALOG) I Please tend me one! D re gw ltem# Desc. Oty . Price Total IIZZT" Addresj_ Phone. 1 1 Wia/MC/Amex Exp. . I Min.Qnter (15.00 — SSH:10%of order + (3.00 In NJ (201) 941-5000 • Fax; (207) 939-8918 ■ CIRCLE 106 ON FREE INFORMATION CARD ,,,.„!.■„■■,■— ameco ELECTRONICS 24 Hour Order Hotline 415-592-8097 w o z o DC o D < DC Math Coprocessors 8088 or 8086 Systems 8087 5MHz $89.95 8087-2 8MH2 SI 29 .95 8087-1 10MHz $169.95 80286 or SQC286 Systems 2C87-10 10MHz S249.95 2C87-12 12MHz $279.95 2C87-20 20MHz $299.95 80386 Systems 80387-16 16MHz $349.95 80387-20 20 MHz $399.95 80387-25 25MHz $499.95 80387-33 33MHz $649.95 SIP Modules 41256A9A-BO 80ns. S56K*9 $54.35 41256A9A-10 100ns. 256K«9 $44.95 421O0OA9A-7O 70ns. 1 Meg $4$\ , 5139.95 VMcuCaH *3dCW Pw.Sjpay $24955 Hn-ViMca Case wMOW Pm. Supply .... SI 49.95 Ro Top Baby XT Tiirtn Casa $6655 Rp-Top Baby ATCase $69.95 EGA & Mult is can Monitor Packages Casper 14" EGA monitor and EGA card package [720 x 350 max. resolution) JE1059 EGA Monitor & EGA Card $459.95 Relisys 1 4" Multiscan monitor and EGA card package (800 x 600 max. resolution) JE2057 Multiscan Monitor S EGA Card $559.95 JE1DS9 IBM PC/XT/AT Compatible Keyboards J E 20 15 84-Key Standard AT Slyle Layout $59.95 FKB4700 101- Key Enhanced Layout w.'l 2 Function Keys.. $69.95 JAMECO IBM PC/XT/ AT COMPATIBLE CARDS JE1043 JEI050 JE1052 JE10S5 GC150O JE1057 J El 060 JE1062 JE1065 JE1071 JE1077 JE108I 360IV720K7t ,2Mb/1 .«Mb Floppy Disk Conlroflw Card (PC/XT/AT) $49.95 Monochrome Graphics Card */ParalFfil Printer Port (PC/XT/AT) ............ $49.95 Co*or Graphics Card w/ Parallel Printer Port (PC/XT/AT) $49.95 EGA Card * 256K Video RAH (PC/XT/AT) ,.. „ $139.95 Orchid 8-Bil VGA Card W/256K Vldso RAM (PC/XT/AT) $169.95 &M6-Bit VGA Card */256K Video RAM (PC/XT/AT) $199.95 po Card w/ Serial, Game. Primer Port a Real Time ctoefc (PC/XT) ........$59.95 RSZ32 Serial Halt Card (PC/XT/AT) $29.95 O Card */ Serial. Game and Parallel Printer Port (AT) ..........-............$59.95 Mulli I/O Card w/ Controller S Monochrome Graphics (PC/XT) $1 19.95 Mulll I/O Card w> 360K/720K/1 2Mb 1 AiVb Floppy Contrcflw (AT) $74.95 2Mb Expended or Extended Memory Card (rero-K on-board) (AT) $1 09.95 Floppy Disk Drives & Diskettes Mitsubishi MF353B 3.5-72t>Kb Internal Dnve ..$99.95 Toshiba 356KU 3.5- t.44Mb Internal Drive 51 09.95 TEAC FD55B 5 ?5" 360Krj Halt hi $89.95 FD55G 5.25" 1.2MB Half HI $99.9S 3.5" & 5.25" Diskettes (10 per box) DSOD 5.25- osdd lat-DKoi $6.95 DSHD 5.25" DSHD (1 2Mb) $13.9S 3DS 3rj- DSDD (720Kb| $16.95 3HD 3.5' DSHD (1.44Mb) $34.95 t MiniScribe Hard Drives & CMS Tape Back-ups Pari Ho. capacity Slyle Average Speed Formal Drive Atone W/S-BII (XT) Controller wne-BJi (AT) Controller M8425 % MMSOJCT OFAS00 M8425 MB425XT M8425AT M842SF M8438 M8438XT MB438AT M8450 MU4S0XT M&450AT M3085 M3085AT 2Mb 20Mb 20Mb 20Mb 30Mb 30Mb 30Mb 40Mb 40Mb 40Mb 70Mb 70Mb 3.5-HK 3.5"HH 3.5"Hrt 3.5'HH 3.5-HH 3,5-HH 3.5-HH 3.5*HH 3.5"HH 3.5-HH 5.25-HH SiS'HH 68ms 68ms 68ms 40ms esms 58ms 68ms 46ms 46ms 46ms 20ms 20ms MFM MFM MFM MFM HLL RLL FLL HLL HLL RLL MFM MFM $22455 $349.95 S249.35 $339.95 $269.95 $299.95 $359.95 $389.95 $429.95 $699.95 $329.95 $599.95 DJ10 40Mb Tape Drive with u p to 1 20Mb capability (includes one TB40 Tape 1 . $299.95 QFA500 150Mb Tape Drive with up lo 500MB capability (includes one TC1 50 tape) $1 049.95 I ■■ ■ Hard & Hard/Floppy Disk Controller Cards MFM Hard RLL Hud MFM llirdrflnppr RLL HinLTioppy Computer Type Pert No./ Price Pin No. /Price Part Ho. I Price Pert No. 1 Prlea SOeS (PC/XT) @ 3:1 Inltrlttva XTGEnVS79.» 10MA27XSS9.95 JElMirSI 09.95 M2K (»TWW r§) 2:1 tnlwlMvi 1K3VUU1,-Sl?i35 lorovsRiijus-as ienvMW2fli49.sS loravstasiw.ss KHJS (*T|.3W ©1:1 IntiriHvi lOOjVt/Vl.JUS.SS 1BBVSR1. -SI 63.55 lb»VUkl2,)1ra.»S I0O6VSR2S1B5.H 1355Shorewisy Road Belmonl.CA 94002 24 Hour Order Hotline (41 S) 592-8097 FAX'S (415) 592-2503 or (415) 595-2664 Telex 175043- Ans. Back: Jameco Bimt Data Sheets - 50c each Send S2. K25 rr*L CATS ACTX-24S2 EJ.25 SERVO MOTOR 3 Vdc nrvo wan paartilomeltr. rat 140 Per connected ID motor variat from ether 500 to rjorjoohma. t.ST X0ja*X1JRB*, o.sr aamafaw tubbar wheel attached to motor ihafl can b* Ljtad aa a capalan v can b* Hatr rvnovad. Pncced *ah opackyi, ebokat and win laada. CATJSVC-2 2 tor 11.00 NJCKEL-CAD BATTERIES IRECHAHGEABLE) AAA SIZE H,S0**<* 1.2M*ta1BQmAh CATS NCB-AAA AA SIZE S2.C0 wch l^SvoBSOOmAn CATS NCR-AA AUSIZE I33ut WITH SOLDER TABS CAT* HCB-SAA CSIZE tl.Huch 1,2vc*a 1200 mAn CATS MCS-C DSI7E S4.a>eacft 1,2 tola 1200 ffJDI CAT* MCB-0 XENON TUBE »= back laada. aaaa) tor etaasaata sash or a ba ba piujt'.n. CATS FLT-3 2 lor II .00 RELAYS ^ 5-« VDCSIP REED RELAY BasM -Ski* Soft BastAosAio se Vdc. 500 ohm oot.S.P.S.T. nor- maty open med relay, 0.5 amp ccetaerj, SIP ooralouralton, CAT* HRLT-SIFJ iiiomii • lOtorstaoo S VDC LATCMMO RELAY Arometa RSLZWY SPOT. (P .™!iy. 5 Vdc .TOsftBi Cfrlt. 1 «td. TU i Wi.lX(mi'C5Ar«0 6 n l j*d.e.767' X 0.3W X 0W CAT* LALY-SDC 12 BO mmdh t3 335 ohm OOfl. S«o*v obf t Izt, -fil* X .*T2* K .4*' hltfi.P.C. mcuril Wflti pint or Dl- 3 kpAdfig. CATt RLT.717 llJOwdt LED CHASER KIT BuikFoua variable apaad led chaser. n rjpnpOorjR B, 10 Ws flash V 1 r\ \ "it ! ye , sequaritially SA an. \~_^^_ A wbanvsf spead ^V^ l! you set them tor. N*;^ Easy IP build Mtlndudes pe board, parti and a> alrucdpna. Ideal tor speaal l^tiUncj arlecu, coa- iumea, &E.Opflra:«on3 BS volts. PC board Is 5" X2.25*- A cjrsatona hour project- CATf AEC $6.50 each SPECIAL PURCHASE210 MFD M0 V PHOTOFLASH CAPACITOR Rubicon CE pholoflash capacitor. 0,79" da X 1 .1" high. These are new capacitors that have been propped with 1 .4" black and red wire leads soldered to the terminals. CAT# PPC-210 $2,50 each 10 tor $22.50 ■ 1 00 for $200.00 22/44 PIN CONNECTOR 'miiiiiiuimiiiiiiirT .156" pin spacing, 0.200' between double rows, gold contacts, P.C. mounting. SPECIAL Same as AMP# 2-530655-6. CAT* EBC-1G SI. 00 each - 10 lor Se.OO ELECTRONIC CAME BOARD Th* L-irwr woTUtaj* q( tbi in«iclrc-TC Szrwb&o Qirrw. OpntH on 6 Vdc. l^lfr+nimricnKlnt. 45bu»on tWH>>-d, 14 liTWaatalo™, 2 I.Cj>. 1 phHO ■N n - m l ■nd odwf bockAh. TapindbotbaTarowof lwyp*d butter* v» rurcston Iwyi, niddw 3 row* tfm a^fjtm^ nanmrvcaa**itiiiUK. fJK.iS' CATiST-4 $l.75eac>i I0fo»:|l5.00 TELEPHONE COUPLING TRANSFORMER FWtwit: «W ohm StyHvday: 600400 ohm OZTKOMi' XMrNjgh 6 p,C pint Dfl 0. 1 ST* CaKTl.WT, Prttiwy Muclina: 300 n?H n*i u , « iW-fci. 1 volt. CATfTCTX-1 t1.2SaKh ■ 10 for »1 1.00 LED'S S TAMO* no JUMBO Di- FUSED 7 1-1'i t:t, mt RES CAT! LED-! H 10 tor 11.50 -100 hvSt3.00 W green CAT* UED-2 II 10 for COO -100 tot SI 7.00 U ffUOW CHTItED-3 10tofS£0Q '100 tor $17X0 PUSHING LED . wfch butt In ItKhhg cticyl "^ opara t aaon swjtt. RED tl.ooaach M CATS UED-t 10 tor 55 50 ft GREEN tl.00»«h I CATS tEB-aa tourte.50 ' BI-POLAR LED (| Udms RED ona dbecttnn, W QAEENftooew.Twokaada, II CATS LED-S 2 lor (1.70 LED HOLDER « 1 1 Tao pace holdar. $J) d CAT* HU=D to tot Bit 10 AMP SOLID STATE RELAY ^ EliCTBOL* S2t7B CONTROL' RaaadSSloloVdc (w»iepa«a oai-S vac). LOAD: to anp # 240 Vac twxisri ?/r. CATS SSRLT-10B SS.SO aa. OUANTtTY DBCOUHT 10 SatflUO- JStot S176J00 SOtorS3D3.DO- lDOtorSSOO.OO OPTO SENSOR wtlh mourning aai*. l.'fi* cpanhn. SM* mounting aan. CAT* osu-a fidcaadi 10r» (4.50 - 100 IM140.CO A.C. LINE CORDS Blacken., 1 0/2. SPT-2 MOH POLARIZED PLUG CATSLCAC 2 lor 1 1.00 10OiorS4S.0D POLARIZED PLUO CAT* LCP-i sot aaeti IDC la KB •untrtBonjiStonT. CALL OR WRITE FOR OUR FREE 60 PAGE OVER 4000 SEND $2.00 POSTAGE PARTS! FOU * CATALOG!! ORDER TOLL FREE 1-800-826-5432 MAIL ORDERS TO; ALL ELECTRONICS P.O. BOX 567 VAN NUYS, CA 91408 LED. FLASHER KIT TwLE.D.^fliiHiln ^t/y \f*0 tK*on ***n i D von -J>-^Jl ^ HH= ^ iv T^taUlridLhdMapiboirit, ^„--— "^ il Th« puii -And Int^ucUom ^jt-^ taw a iimui rw^w tfrttjJL a l>mc* v^Mty pfTjfofa tgr inygfa* wfrh t-*»t «Jd*MfRj iU*. CATi LEDHT fl.TSpwhM 100K WHAT $1.00 WILL BUY »**l /*"*, 200 ASSORTEO 1/4 WATT FES1STORS Bent Itada, carbon oomp. and carton fam. CATI ORES It. 00 per ataortmanl 200 ASSORTED ^*5o^ Mi WATT RESISTORS -CCQ-, Bam laada, carbon camp, and llm, CAT* GRAftRE $1.00 par aaaortmant ft ff 50 ASSORTED DISC CAPACITORS Moel ara cm tp.c. toads). Soma to 500 von*. CATS ORABOC S 1.00 par asaonaien! 15 VALUES OF ELECTROLYT1CS Cemalna botn ulal and radial alytoe Iront 1 mid. CAT* Q.HABCP H.00 par LOOK WHAT $2,00 WILL BUY 19 AMP SflAP.ACTlON SWITCH Sptocaaola 95amp 12ajc50Vacnormaay opal awach. Body It tiwxsvrxsr. Buoon axtanda I'l S" abov* iwtch body, CAT* GJUBiaS 12.00 p INFO: (818)904-0524 FAX; {818)781-2653 MINIMUM ORDER $10.00 QUANTITIES LIMITED CALIF. ADD SALES TAX USA: $3.50 SHIPPING FOREIGN ORDERS INCLUDE SUFFICIENT SHIPPING. NO C.OiD. ^fflr^ff' 92 CIRCLE 107 ON PREE INFORMATION CARD ZJZZ* WORLD ;* JDR caters to the developer with a full tine of prototyping & programming products. Request our catalog tar the complete line! MODULAR PROGRAMMING SYSTEM MODULES USE A COMMON HOST ADAPTOR CARD- 1 SLOT PROGRAMS EPROMS, PROMS, PALS, MORE! HOST ADAPTOR CARD '29.95 • UNIVERSAL INTERFACE FOR ALL PROGRAMMING MODULES! ■ SELECTABLE ADDRESSES PREVENTS CONFLICTS -MOLDS) CABLE MOD-MAC UNIVERSAL MODULE $ 499.95 ■ PROGRAMS EPROMS, EEPROMS, PALS, SI POLAR PROMS. B74B S 8751 SERIES DEVICES; 16VS AND J0V8 SALS (GENERIC ARRAY LOGICJFROM LATTICE. NS, SGS ■ TE5TS TTL. CMOS. DYNAMIC I STATIC RAMS • LOAD DISK. SAVE DISK. EDIT. BLANK CHECK. PROGRAM. AUTO, READ MASTER. VERIFY AND COMPAHE • TEX TOOL SOCKET FOR 3"-S"W. IC'S ( B.4H PINS) MOD-MUP MOD-MPL-SOFTcupl software ... , $99.95 EPROM MODULE • PROGRAMS 24-31 PIN EPROMS. CMOS EPROMS I EEPROMS FROM 16K TO I024K • HEX TO OBJ CONVERTER -AUTO. BLANK CHECK/PROGRAM/VERIFY - VPPS, 12.5, 12.75, 13.21 I 2S VOLTS- NORMAL. INTELLIGENT. INTERACTIVE S OLIICK PULSE PROGRAMMING ALGORITHMS MOD-MEP OTHER MODULES: PAL PROGRAMMER. DIGrTAL TESTER. Bl- POLAR PROGRAMMER. MICROPROCESSOR PROGRAMMER - FROM JI29.B5 TO S259.9S- CALL FOR INFORMATION *119.95 EPROM PROGRAMMER *129.95 t> ■ PROGRAMS 27XX AND 27XXX EPROMS UP TO 27512 ■ SUPPORTS VARIOUS PROGRAMMING FORMATS S VOLTAGES ■ SPLIT OR COMBINE CONTENTS OF SEVERAL EPROMS OF DIFFERENT SIZES -READ, WRITE. COPY, BLANK CHECK S VERIFY - SOFTWARE FOR HEX AND INTEL HEX FORMATS MOD-EPHOM EPROMS 27128 16384*8 250m 12.5V 28 4.25 271 25 A -2,30 15304x3 20Qre 12.5V 28 5.35 PARTIAL LISTINGS ONLY ■ MAN Y OTHERS AVAILABLE! EPROM ERASERS DATABASE 11 *39,95 • SH1RT POCKET SIZE! •ALL SIZES UP TO 4 AT A TIME ■ ERASES MOST EPROMS IN 3 MINUTES □ATA RASE II PE-140T SPECTRONICS 9 CHIP ERASER W/TIMER ...1139.95 PROTOTYPE CARDS FR-4 EPOXY CLASS LAMINA re WITH GOLD PLA TED EDGECARO FINGERS AND SILK SCREENED LEGENDS nmxr JDR-PH1 WITH iSVANO GROUND PLANE 27.95 JDR-PR2 ABOVE WITH 110 DECODING LAYOUT .29.95 JDR-PR2-PK PARTS KIT FOR JDR- PR2 ABOVE ,8.95 FOR AT JDR-PR10 15-BITWITH I/ODECOD1NG LAYOUT ....34.95 JDR-PH10-PK FARTSKIT FOR JDR-PR10 ABOVE 12^5 £ X TENDER CARPS SIMPLIFY PROTOTYPING AND TESTING EXT-8088 8-BIT FOR BOSS MOTHERBOARDS .... 29*5 EXT-882W 1 6 BIT FO R 28&3S6 MOTHE HBOARDS 39.95 UPGRADE YOUR OLD SYSTEM! REQUEST OUR NEW FLYER TO LEARN HOWI BUILD YOUR OWN 286 SYSTEM FOR UNDER $650 ITS A GREAT WAY TO LEARN AND A GREAT WAY TO SAVE! 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INFORMATION(402)554-041 7 Orders Call Toll Free 1-800-624-1150 M.D. ELECTRONICS 115 NEW YORK MALL SUITE 133E OMAHA, NE. 68114 M.C, VISA £.Q.n. ADVERTISING INDEX — Short Circuits .18 192 Smith Design ,14 74 Solid State Sales 85 — Star Circuits 25 83 Synergetics 64 188 TECI 79 92 Tektronix 7 123,185 Test Probes 13 207-210 Test Probes 13 183 Unicorn 84 195 U.S. Cable 62 64 Video-Link 86 181 Viejo Publications 71 182 WPT Publications 79 RADIO-ELECTRONICS does not assume any responsibility for errors that may appear in the index below. Free Information Number Page 108 AMC Sales 46 193 Ace Communications 79 75 Ace Products 21 107 All Electronics 92 — Amazing Concepts 85 106 American Design Components ... 89 77 B&K Precision CV4 67 Banner Technical Books 14 98 Beckman Industrial 5 109 C&SSales 30 70 CEI 87 — C1E 15 196 Cable Network 88 54 Ciicml t'onics . 11 — Command Productions 16 178 Communications Specialists 79 55 Contact East 21 58 Cook's Institute 46 197 D&D Electronics II — Damark International 69 127 Dcco Industries 21 179 Electronic Goldmine .82 — Electronics Book Club 36 — Electronic Tech. Today 78 121 Fluke Manufacturing CV2 — Friendly Videos 16 186 Global Specialties 17 — Grantham College 20 86 Hcathkit 25 184 International Components Corp. . 88 1 13,170 JDR Microdevices 93 114 Jameco 90.91 104 Jan Crystals II 180 Jinco Computers 94 190 Joseph Electronics 23 — King Wholesale 82 53 MD Electronics 94 93 Mark V. Electronics 81 — McGraw Hill Book Club 26 61 Microprocessors Unltd. 77 — NR1 Schools 9 19 1 Optoelectronics CV3 — Pacific Cable 83 56 Parts Express 87 101 Pomona Electronics 3 78 Radio Shack 19 187 Royer Associates 21 194 SCO Electronics 62 177 Sencore 23 ADVERTISING SALES OFFICE Gernsback Publications, Inc. 500-B Bi-County Blvd. Farmingdale. NY 11735 1 (5 16) 293-3000 President; Larry Stockier Vice President: Cathy Stockier For Advertising ONLY 516-293-3000 Fan 1516-293-3115 Larry Stockier publisher Arline Ftshman advertising director Dcnise Haven advertising assistant Christina Estrada advertising associate Lisa Strassman credit manager Subscriber Customer Service 1-800-288-0652 Order Entry for New Subscribers 1-800-999-7139 7:00 AM • 6:00 PM M-F MST SALES OFFICES EAST/SOUTHEAST Stanley Leuitan Eastern Sales Manager Radi o- El ectroni cs 259-23 57th Avenue Little Neck, NY 1 1362 1-718-428-6037,1-516-293-3000 MIOWEST/Texas/Arkansas/Okla. Ralph Bergen Midwest Sales Manager Radio -Electronics 540 Frontage Road — Suite 339 North lie Id. IL 60093 1-312-446-1444 Fax 1-312^146-8451 PACIFIC COAST/ Mountain States Marvin Green Pacilic Sales Manager Radio- Electro n ics 5430 Van Nuys Blvd. Suite 316 Van Nuys.CA 91401 1-818-986-2001 Fax 1-818-986-2009 CIRCLE 53 ON FREE INFORMATION CARD 94 I OPTOELECTRONICS The only name in HANDI-COUNTERS Check These Incredible Features On The All New UTC3000 • 10Hz to 2.4GHz Range. Simply amazing! • 10 Digit LCD Display. 1Hz resolution to over 150 MHz direct. Readable in bright sunlight. • RF Signal Strength Bargraph. 16 Segment, Zero, & Full Scale adjustment. SEE the input signal! ■ Super Sensitivity.