Radio-Electronics-19

JULY 1990

TECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE BUILD R -E's ^r, DIGITAL DASHBOARD Add hi -tech monitoring to any car

BUILD A SUPER DIRECTIONAL MICROPHONE Our novel design gives you long-distance ears ADD A DISPLAY TO YOUR PROJECT How to use multi -line LCD displays DtSP` DISP2 D 1f . ROCK, RELIGION, & RHETORIC A look at U.S.-based shortwave stations CIRCUIT COOKBOOK Alarm generator circuits and fault indicators for your security system

BUILD A SOLID STATE DISK DRIVE (Li3L;t

Use static RAM to speedP u P i your computer and save wear and tear on your mechanical drives

GERNSBACK PJELICATION

www.americanradiohistory.com Better resolution and accuracy can change the whole picture.

Clear up the uncertainty in your motors, radar, or other transmitters. And test measurements with these three thirty-six components are dedicated to versatile Fluke multimeters. high-energy overload protection, for you When you need performance that leaves and the meter. no room for doubt, focus on the Fluke 25, All three instruments offer simplicity of 27 and 37 Analog/Digital Multimeters. operation. Select functions with one rotary With their patented A/D converters, they dial. Don't worry about range selection deliver DC volts accuracy within 0.1%. An - it's automatic. Plus, the auto -polarity easy-to -view display also provides a full digital readout and analog bar graph give 4 digits of resolution for readings up to you two ways to look at the signal. The 27 FLUKE 25, 27, & 37 and 37 also add extra features like MIN/ 3200 counts. 0.1% basic dc accuracy Fully sealed, drop proof cases protect MAX Recording and Relative mode. Analog/Digital Display amps, diode test Fluke 25 and 27 from abuse Next time you make a measurement, Volts, ohms, the handheld 0.1 uA to 10A, all fused missing. Then call on the job site. The unique design of the think about what you're 30 KHz ac bandwidth 100 ),V to 1000V ac and dc is well suited for benchtop and us toll -free 1 -800 -44 -FLUKE, ext. 33 Fluke 37 Touch Hold"' function portable use, and includes a convenient and ask about the Fluke 25, 27 and 37 Relative (difference) mode and MIN/MAX recording mode (27 & 37) handle, storage compartment (37). for test leads and meters. You'll get the picture. Integral storage compartment Three-year warranty (25, 27). Two year warranty (37) small accessories. The circuitry in each model is shielded FROM THE WORLD LEADER to eliminate interference - even near IN DIGITAL MULTIMETERS FLUKE

John Fluke Mfg. Co.. Inc.. P 0. Box C9090. M/S 250C, Everett. WA 98206, Sales.1206) 356-5400 Other (2061347-6100. Copyright 1988 John Fluke Mfg. Co.. Inc All rights reserved. Ad No. 0280-F20 CIRCLE 121 ON FREE INFORMATION CARD

www.americanradiohistory.com Radio .duly 1990 Electronics Vol. 61 No. 7

BUILD THIS BUILD R -E's e DIGITAL 31 R -E -'s DIGITAL DASHBOARD DASHBOARD Give your dashboard a facelift with.six attractive, and accurate new gauges. Ross Ortman 41 SUPER -DIRECTIONAL MICROPHONE Our build -it -yourself model outperforms many store-bought models! Dale B. Blackwell 45 THE LAWN RANGER: PART 2 A look at the robotic lawn mower's motor control board. Raymond Rafaels

PAGE 31

50 ADD A DISPLAY TO YOUR PROJECT COMPUTERDIGEST Installing the alpha -numeric display in your project. Mg Steven Avritch BUILD A SOLID-STATE EDITOR'S DISK DRIVE WORK- BENCH . "Z. 56 SECURITY SYSTEM COOKBOOK I,..-. J An assortment of security circuits to build for your home and car. ' Ray Marston TECHNOLOGY 53 ROCK, RELIGION, AND RHETORIC Tune in to privately owned, U.S.-based shortwave stations. Gerry L. Dexter

PAGE 75

75 BUILD A SOLID-STATE DISK DRIVE Retain important PC data with our inexpensive battery -backed RAM disk. Mark Hatten AND MORE 94 Advertising and Sales DEPARTMENTS Offices 94 Advertising Index 6 VIDEO NEWS 69 AUDIO UPDATE What's new in this fast - Taking care of your tapes. 8 Ask R -E changing field. Larry Klein 95 Free Information Card David Lachenbruch 14 Letters 18 EQUIPMENT REPORTS 72 DRAWING BOARD Scrambling and Macrovision. 82 Market Center Tektronix analog/digital- Robert Grossblatt storage oscilloscope. 25 New Lit HARDWARE HACKER WORKBENCH 62 75 EDITOR'S 21 New Products Power -control fundamentals. Reader mail. Don Lancaster Jeff Holtzman 4 What's News

www.americanradiohistory.com ON THE COVER Radio Electronics If your car's "instrument cluster" Hugo Gernsback (1884-1967) founder (commonly known as a dashboard), M. Harvey Gernsback, consists primarily of idiot lights that editor -in -chief, emeritus

don't provide all the information you Larry Steckler, EHE. CET, want, take a look at our digital editor -in -chief and publisher dashboard. We show you how to put EDITORIAL DEPARTMENT together six digital gauges: voltage, Brian C. Fenton, editor oil pressure, water temperature, fuel Marc Spiwak, associate editor level, vacuum, and an auxiliary dis- Daniel Goodman, technical editor Teri Scaduto, play whose function you can choose. assistant editor Jeffrey K. Holtzman Not only do these gauges give accu- computer editor rate, detailed level readings, they Robert Grossblatt, circuits editor also look good. To give your Larry Klein, audio editor David Lachenbruch dashboard an updated, high-tech contributing editor look worthy of the name "instrument Don Lancaster cluster," turn to page 31. contributing editor Richard D. Fitch contributing editor Kathy Campbell, editorial assistant ART DEPARTMENT 1 4 1t } I, Andre Duzant, art director Injae Lee, illustrator Russell C. Truelson, illustrator THE AUGUST ISSUE PRODUCTION DEPARTMENT Ruby M. Yee, production director GOES ON SALE Janice Box, editorial production JULY 3. Karen S. Tucker advertising production Marcella Amoroso production assistant BUILD A VIDEO GRABBER CIRCULATION DEPARTMENT Capture a frame of video and manipulate it on your computer. Jacqueline P. Cheeseboro circulation director Wendy Alanko BUILD A 100 -MHz FREQUENCY COUNTER circulation analyst An easy -to -build, accurate instrument based on the Intersil 7216. Theresa Lombardo circulation assistant AC POWER MEASUREMENT Michele Torrillo, reprint bookstore A refresher course. Typography by Mates Graphics Cover photo by Diversified Photo MICROWAVES Services A look at the many uses of microwaves in the past, present, and future. Radio -Electronics is indexed in Applied Science & Technology Index and Readers Guide to Periodical Liter- BUILD A TELEPHONE-LINE CONTROLLER ature. A programmable card that lets your computer control incoming and Microfilm & Microfiche editions are outgoing calls. available. Contact circulation department for details. Advertising Sales Offices listed As a service to readers. RADIO -ELECTRONICS publishes available plans or information relating to newsworthy products, on page 94. techniques and scientific and technological developments. Because of possible variances in the quality and condition of materials and workmanship used by readers, RADIO -ELECTRONICS disclaims any responsibility for the safe and proper Radio -Electronics Executive and functioning of reader -built projects based upon or from plans or information published in this magazine. Administrative Offices: 1-516-293-3000. Since some of the equipment and circuitry described in RADIO -ELECTRONICS may relate to or be covered by U.S. patents. RADIO -ELECTRONICS disclaims any liability for the infringement of such patents by the making, using, or selling of any such Subscriber Customer Service: equipment or circuitry, and suggests that anyone interested in such projects consult a patent attorney. 1-800-288-0652. Order Entry for New Subscribers: RADIO -ELECTRONICS, (ISSN 0033-7862) June 1990. Published monthly by Gernsback Publications, Inc.. 500-B Bi -County Boulevard, Farmingdale, NY 11735 Second -Class Postage paid at Farmingdale, NY and additional mailing offices Second-Class 1-800-999-7139. mail registration No. 9242 authorized at Toronto, Canada. One-year subscription rate U.S.A. and possessions $17.97. Canada $23.97, all other countries S26.97. All subscription orders payable in U.S.A. funds only, via international postal money order or check drawn on a U.S.A. bank. Single copies $2.50. c 1990 by Gernsback Publications, Inc. All rights reserved. Printed in U.S.A. fhe POSTMASTER: Please send address changes to RADIO -ELECTRONICS, Subscription Dept.. Box 55115, Boulder, CO 80321-5115. Audit Bureau A stamped self-addressed envelope must accompany all submitted manuscripts and/or artwork photographs if their return is or of Circulation desired should they be rejected. We disclaim any responsibility for the loss or damage of manuscripts and/or artwork or photographs while in our possession or otherwise.

www.americanradiohistory.com PLUG IN. TURN ON. GET DATA. FAST. FREE SOFTWARE. NO PROGRAMMING.

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www.americanradiohistory.com WHAT'S NEWS

New earth -to -orbit launcher will use electromagnetism A new technology that might be used to launch small satellites from earth to orbit, currently being de- LAS BLDG. veloped ASSFuaY BLDG INJECTOR SUPPORT BLDGS. by Sandia National Labora- STAGING MAGAZINE LOADING - tories (Albuquerque, NM), uses STORAGE / ASSEMBLY electromagnetic induction and in- PRIME POWER volves no sliding electrical contact between the projectile and the barrel. Providing an alternative method to rockets for the launching of satellites up to 1,000 pounds, it could LAINON / DATA JRAQ4NG SYSTEM have potential military and commer- I!/ coNTROL / TELEMEfRi cial applications. In the new launcher, the projectile passes through a series of cyl- indrical coils that form a contactless barrel. Just before firing, a pneu- A FUTURE FULL-SCALE EARTH -TO -ORBIT electromagnetic launch system might matic device sets the projectile spin- look like this. The flyway, consisting of hundreds of stages, is built up the side of a hill to ning, for aerodynamic stability. The present a 30 -degree launch angle. firing is under electronic control: One after another, coils are ener- 4.5 km/sec, to achieve orbit velocity. gized by a heavy capacitor dis- The combination of electromag- charge, accelerating the armature netic and rocket techniques re- forward down the length of the duces costs and risks for the flyway. Between each coil, a high- electromagnetic launch. speed optical -fiber sensor mea- Still in the exploratory develop- sures the precise position and ve- ment phase, the work has achieved locity of the projectile and instructs a record velocity for contactless the computer to fire the next coil at electromagnetic launchers of 1 kilo- the right instant to provide max- meter per second with a 160-gram imum effect. The launch mass for a projectile. Experiments are now un- full-scale earth -to -orbit projectile derway with a larger, six -stage would include an iron or other mag- launcher that fires a 4 -kilogram (10 - netizable armature, a removable SANDIA EXPERIMENTER Ronald Kaye in- pound) projectile that is 5Y2 inches aeroshell, small rocket motor, and serts a projectile into the breech of a six - in diameter. Subsequent develop- stage electromagnetic launcher, which is the payload. An existing mockup re- ment stages will focus first on still being developed as a possible alternative sembles a small rocket or a very to rockets for frequent launches of small larger launchers. After that, the con- large artillery shell, with the tapered payloads. cept would be scaled up further by aeroshell streamlined to reduce at- adding more stages to the launcher, mospheric friction. The electromagnetic launcher increasing the length of the flyway A sophisticated code called would provide enough velocity- along which the launch mass is ac- "WARP 10" has been used to sup- about 4.5 kilometers per second at celerated. For earth -to -orbit launch, port the experiments. The code has the end of the flyway-to send the the flyway would consist of multiple successfully predicted the results of main part above the earth's atmo- stages, each powered by its own ca- all of the experiments made so far. sphere (the armature would drop pacitor bank, and elevated at a 30 - Its predictions for scaled -up ver- away shortly after launch). Once the degree angle. The technology sions of the electromagnetic launch projectile was above the atmo- seems especially promising for the system are making scientists ex- sphere, the aeroshell would drop economical launching of large num- tremely optimistic that the larger away and the rocket motor would bers of relatively small objects into systems will also be successful. step up the velocity about another earth orbit. R -E 4

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www.americanradiohistory.com VIDEO NEWS DAVID LACHENBRUCH, CONTRIBUTING EDITOR Ghostbuster tests. The first major and its affiliate Polygram in hopes that the magic American test of automatic ghost cancelling was of the CD boom would rub off on videodiscs. The pronounced a rousing success, and there were two companies retreated in early 1990, and the predictions that anti -ghost technology could be name reverted to laserdisc. But today's players put into the FCC's broadcast standards before the take advantage of most recent laserdisc's year is out. The exorcism occurred in Atlanta, the compatibility with audio CD's, and almost all of site of the 1990 convention of the National the new players can play CD's as well as LD's. The Association of Broadcasters, where six television new laserdisc players also have copied from stations used the ghostbusting system Super VHS, by using Y/C (luminance and developed-and now in use-in Japan. As chrominance) outputs to plug directly into "S - reported here (Radio -Electronics, November connectors" on high -resolution TV sets. 1989), the system employs a "training pulse," broadcast in the vertical interval (in Atlanta it Full -Motion CD -I. The Compact Disc - was line 18), which instructs specially equipped Interactive (CD -I) system has added something TV sets ;o remove ghosts and accept the true new that makes it far more significant as a image. Observers of the demonstrations at the consumer product: full motion. The system convention were impressed with its performance. espoused by Philips and Sony has suffered in the Set -top tuners equipped with ghostbusters are past in comparison with Intel's Digital Video currently selling in Japan for $700-$1,000, but Interactive (DVI) system. The addition of full more -integrated, chip -based systems built into motion to the digital CD -I system makes it a very television sets are expected to be much cheaper. potent potential product of the 1990's. A standard Although other ghost-canceling systems have 5 -inch compact disc recorded in the CD -I mode been proposed-notably by AT&T, Zenith, and the now can provide up to 72 minutes of full -motion David Sarnoff Research Center-the Japanese digital video plus digital audio. As demonstrated system now has the inside track because of the recently by Philips, the picture quality of the CD -I successful Atlanta tests and its proven quality in disc was virtually indistinguishable from everyday use in Japan. videotape. The system is scheduled for marketing next year in the U.S. and Europe. It also has the Laserdisc shortage. When laser optical potential to become an important movie -carrying videodiscs' popularity slumped almost to nothing medium. As a digital -video system, the same disc a few years ago, who would have thought they can be played on the American and Japanese would become so popular in 1990 that there NTSC system, the European PAL system, or any would be a severe shortage of programs? Thanks other color TV system. to the influence of the compact disc, the laserdisc While the Intel DVI system is designed for now has become the preferred playback medium playback using a computer (and isn't intended to of videophiles. With about 10 brands of players be a consumer product), CD -I uses a player that either on the U.S. market or about to enter it, and resembles an audio CD player. Philips says that player sales expected to double this year to DVI takes several hours to record an hour of 250,000, disc manufacturers are hurrying to try video, but CD -I can record in real time-requiring to relieve the shortage. The latest to go into only an hour to record an hour of video. Philips' videodisc pressing in the United States is Sony, enthusiasm about CD -I is best summarized by a whose Digital Audio Disc Co. plant in Terre quotation from a company official: "CD -I is what Haute, IN, is adding videodiscs to its compact -disc publishers have been waiting for since the 1450's, manufacturing ability. when Johann Gutenberg produced the first The videodisc's comeback started, ironically, printed version of the Bible. We have pushed CD -I with the ballyhoo for an unsuccessful product- full -motion video far beyond DVI. There is no Compact Disc-Video-a name coined by Philips discussion any more." R -E 6

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RING MY PHONE There is not enough line current to ring the telephone bells in our house. Either we're too far out or there are SFS t V /B too many phones on the line. Is there T e *l /NE G any other way I can get the phones to -1N*--- z OSCR% TNC /7 ring?-G. Myers, Meridian MS To Pf10/I/E 200k Before we start on this, and by the .Z.//VE OSCRIn DI way the answer is yes, let me tell you /S OSCRo OUT I) that I haven't heard of a problem like 300,oF this in a long time. In these post - CE/7"», 2-4'4;4,-%2-4'4;4,-%K L /8,e zk 3I Bn divestiture days, most phones have '3CTm oir i gone a long way from the original ("1 Western Electric 2500 series. CMOS /zV os :To OTc ZENfR /ook /N47512 /oME has replaced most of the circuitry in -bN1r A/M LW -MM- the old phones and I haven't seen a real carbon granule in years. 5/k G 44 EN The popular lore and certain legends have it that the telephone line voltage is fixed at a value written in

stone. Nothing could be further FIG. 1 from the truth. It has never been promised by the telephone compa- to Clara, CA 95051 (408) 246-0330). Once upon a time, doing some- ny that you'll find 50-volts DC on - The chip you need is their S2561-a thing like that was a real pain in the hook, 5 -volts DC off -hook, and a 90 - dedicated telephone -ringer IC that neck, since you had to do analog volt AC ringing voltage. can be powered directly off the decoding of the frequencies in the All the phone company guaran- phone line. You can use a battery if high and low groups used for DTMF tees is that the phone circuit is a 20- you're afraid of loading the line. (Dual Tone Multi Frequency) tones. milliamp line. As a historical note, The chip doesn't need much sup- Fortunately, this is America, and that's interesting because 20 -milli - port to make it work, and everything capitalism usually fills any consum- amp current loops have been you could want to know about it is er needs that show up in the mar- around for a long time. But this isn't described in the data sheet. The cir- ketplace-and that is even true in helping you solve your problems. cuit in Fig. 1 shows you what has to the world of semiconductors. The development of CMOS- be done to put the IC to work. You Several manufacturers make based telephone parts has resulted can use it to drive a small speaker, DTMF decoders, including such in a sort of revolution in telephone since the chip puts out up to 50 well-known names as National, design. Given a 20-milliamp limit, milliwatts when you power it off 10 AMI, and Mostek. I'm not listing any most phone manufacturers have volts. As an alternative, you can feed of the chip numbers because each been able to design multi -featured the output to an amplifier and get of those companies have several of telephones that draw their power even more gain. them and which one you use de- directly off the phone line. Just pends entirely on what you want to about the only use for batteries is to TOUCH TONE DECODER do. Call or write them and get your- preserve memory in phones that let I've been trying to design a circuit self a handful of data sheets. you store numbers. that would decode Touch Tone fre- What all of the decoders have in Several semiconductor manufac- quencies and display them on LED's. common, though, is that they de- turers make chips that are designed So far, the best I've been able to do is code only the incoming frequency with your specific application in less than what I want. Can you point and put out a binary equivalent. If mind. An example of those is made me in the right direction?-W. Brown, you want to build something that by AMI (3800 Homestead Road, San - Golden CO can display a dialed number, you're

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www.americanradiohistory.com Pomona's going to have to work out a circuit own a good CGA monitor, it seems a that can store the number being de- shame to have to junk it and spend the coded and then be able to display at money necessary to get a VGA Boxes Are least ten digits --more if you use ac- monitor. Isn't there something simple cess codes. could do to my CGA monitor to make Several of these circuits have ap- it compatible with my VGA card?-F. peared on the pages of Radio -Elec- Ischer, New York, NY Everything tronics over the years and, of course, Believe it or not, there's a simple there are some chips, such as Na- way you can do that. It takes some tional's MM74C9XX series, that work but it can be done. Remove But Wired. make the job really simple. It's pos- the power cord from your CGA sible to design a circuit to do the job monitor and attach it to a VGA with two or three IC's, a handful of monitor. When you're finished, the passive parts, and the displays new monitor will work perfectly. themselves. But seriously folks, there's no other way.

50 -Hz TAPE SPEED I suppose it's possible to modify I have a European cassette recorder all of the circuitry in the CGA that was designed to run at the correct monitor to handle VGA, but I'm speed with 50 -Hz AC. Is there any sure it's not an easy thing to do. And way, without changing the pulleys and even if you were able to do it, I'm belts, to have the machine run correct- not sure the phosphor in the picture ly in the USA?-F. Peterson, Brampton tube has a long enough persistence ONT to be usable for VGA. A safe bet There's a way to do anything, but would be no. that doesn't make everything worth VGA scan frequencies are about doing. You could have the machine double those of CGA, and you run at the correct speed by building would have replace so many parts in When you're looking for just the right a 50 -Hz AC generator capable of the CGA monitor that you'd more box for your connections, we've probably putting out as much power as is re- than likely have nothing of the old got it. Good chance it's even in stock. Ther- quired by the recorder. But that is one in use except the case. Nobody moplastic, Phenolic, Extruded Aluminum or not a trivial task. likes saving a buck more than I do, Die -Cast Aluminum. Plain or with connectors; Some machines have a dual - but this is definitely one of those BNC, UHF, Type N, Binding Posts, Banana Plugs, or any combination of the same. pulley system, so that the speed can times when it's better to rob the pig- be adjusted by moving the belt from gy bank than warm up the soldering Dependable Choices. All you need to one groove to another. If worry about is your circuit. There are dozens that isn't iron. of standard choices true in your case, the next step including rugged would be to contact the manufac- TELLING SCR'S FROM TRIACS connectorized boxes turer and see if they can sell you a I recently bought a bag of mixed that won't let you down. replacement pulley for 60 -Hz opera- SCR's and Triacs. Since the parts aren't Lids and screws are included. tion. The voltage can be taken care easily marked, I'm having a hard time See your nearest Authorized of with a small transformer, as I'm telling the SCR's from the Triacs. Do ributor or contact sure the machine doesn't use a great you have some simple circuit I can NA ELECTRONICS, deal of power. use?-D. Koetting, St. Louis, MO. . Ninth St., I know you're really looking for a The following method is an easy ox 2767, different kind of answer but, believe way to solve your problem: An SCR Pomona, CA 91769 is a DC device, and a Triac is an AC (714) 623-3463 me, this is the best way to do it. You device. The FAX (714) 629-3317 may think of having to change former conducts one pulleys as a pain in the neck, but it's way only, while the latter conducts a piece of cake compared to the both ways. A battery and bulb let FREE brain damage involved in designing you find out which are which. Put 1990 CATALOG! circuits from the ground up. And, in the bulb in series with the battery Thousands of test any event, opening up the machine and connect the two leads to the solutions and large legs of the device. accessories m and changing a pulley isn't really this neu;138-page that big a job. It's easy, sometimes, Use a piece of wire to momentari- handbook (3 quake products to get so involved in something ly connect the third leg to each large

R's Free! Call or write today leg, one at a time. If the bulb doesn't (o you're trying to do that you forget z what you were trying to accomplish light, reverse the battery polarity o when you first started. and do it again. If you can't get the U bulb to light at all, the part is either Jw CGA TO VGA dead or another kind of device. If it w ó ITT Pomona I have an IBM-compatible comput- lights one way only, it's an SCR, o AN ITT EMC WORLDWIDE COMPANY er and have just upgraded my display whereas if it lights both ways, it's a Discover our strengths. from CGA to VGA. Since I already Triac. R-E 12 CIRCLE 101 ON FREE INFORMATION CARD

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AMATEUR SCIENTIST'S WISH SCIENCE Tupperware to store ammonium- This is just a quick note to let you persulfate. Nothing was mentioned know how much I enjoy Don Lan- about labeling the container! caster's "Hardware Hacker" col- the Amateur Scientist's Journal Chemicals should never be stored umn. The topics presented are LIGHTNING in unmarked containers, and in the extremely interesting and diverse. Your camera can capture case of Tupperware, he clamorous cause of both the lid and only wish more such information, nature's cacophony the container should be labeled. Re- articles, and publications were avail- member, someone else coming able to the amateur scientist, inven- KILLER BEE upon the container doesn't have the IDENTIFICATION tor, and general tinkerer. Many Is it domestic? knowledge of what's inside. s it a killer? Electronic circuit years ago-well before my time-a detects the invader! PH I LL LEYVA number of publications existed for MINIATURE Hollister, CA the amateur experimenter. But to- TRACKING TRANSMITTERSeters day, unfortunately, only two really that you can assemble 1oeieht! POLARITY POINTERS

useful regular columns (that cover AERIAL Like many people, I tend to get fields other than computers and PHOTOGRAPHY FROM KITES PECIAL behind in my reading, and just re- Tips and CRTh1ENTS electronics) exist that I know of: Ra- that makegadgetsd possible! cently had the opportunity to catch dio -Electronics' "Hardware Hacker" up on the January 1990 issue of Ra-

and Scientific American's "The Ama- dio -Electronics. I enjoyed the article teur Scientist." entitled "Telephone Mute Switch," On another note, the gremlins at- the device that's used to turn off the tacked your April column by sub- puters," "The Scientist, " and much, stereo or TV when the phone rings.

stituting iridium (sic) for indium in much more. However, there was one point that I the 117 alloy. I volunteer to purchase They will be sending out sub- feel should have been emphasized all the 20% iridium alloy anyone will scription materials as soon as to the readers constructing the proj- sell me at $78.00 per pound, and I'll they're available. But if you want to ect. retire rather quickly! start today, you can become a Tip and ring are very important, ROBERT N. WILLIS Charter Subscriber right now. It will but the article failed to mention that Stone Mountain, GA be starting with four issues a year. the project is polarity sensitive. If tip The cover price in the U.S. will be and ring are wired backwards in the Your wish has come true. This $3.50 per issue, and you can order user's house, which is very common September, the magazine you have your 4 -issue subscription for only in older homes, the phone will re- been asking for will be available. It's $9.95. Write to Science Probe!, main off -hook forever. To avoid that, called Science Probe, The Amateur Subscription Dept., P.O. Box 54098, check the line for polarity. If no dial Scientists Journal, and it does exactly Boulder, CO 80321-4098. Be one of tone is heard when the project is what you're looking for. Just scan the first to enjoy this unique pub- connected, simply reverse tip and the titles on the first issue (its cover lication!-Editor ring, the red and green wires men- is shown above)-"Lightning-How tioned in the article. to Capture it With Your Camera;" PROPER STORAGE PROCEDURES ERNEST SCHMELTZER

"Killer Bee Identification An Elec- Each month when I receive my PCU, Inc.

tronic Device that Makes Identifica- copy of Radio -Electronics, I look for- Midland, TX tion a Snap;" "Miniature Tracking ward to seeing what new toys and Transmitters-Two Tested Radio sweets Don Lancaster has in his IN PRAISE OF THE MAC Transmitters that Anyone Can "Hardware Hacker" column. I'm al- The article concerning Microsoft Build;" and "Aerial Photography ways looking for new information or Windows in December's Editor's from Kites-Tips and Gadgets that a different view on how to do Workbench was interesting in its Make it Possible. "And then there's a things, and he always has some discussion of the graphic interface. wide range of special departments great input! Although I've never used Windows, to grab your interest. They include I was disturbed by something in I'm an old window -hacker on my "Science Fair News," "Communica- the April "Hardware Hacker." On Mac. It surprises me that after four tions Facts," "Field Reports," "Com- page 59, we are told to use years of development the DOS 14

www.americanradiohistory.com world has yet to implement a consistent, high -quality graphic interface for its machines. C-kDI V is T The command line interface clearly obsolete, a holdover from DescrAmbler Article Parts the days when personal computers We stock the exact parts, PC Board and AC Adaptor had 64K (or less) of memory. Even for two articles published in Radio -Electronics magazine the original 128K Mac successfully on building your own CABLE TV DESCRAMBLER demonstrated the graphic interface. Practically all new software is menu - February 1984 issue February 1987 issue driven, but the blank screen of DOS #701 Parts 19.00 #301 Parts 29.00 is always waiting. Includes all original parts. Includes all original parts. As stated in the article, the Mac is #702 PC Board 7.95 #302 PC Board 7.95 a finely crafted piece of equipment. Original 3x4 etched, drilled Original 5x8 etched, drilled and pc board. When I launch a new program, I feel and silk-screened pc board. silk-screened confident that it will run on my ma- #704 AC Adaptor 7.95 #304 AC Adaptor 7.95 chine with no need for tinkering, Original 18 Volt DC e 200ma. Original 18 Volt DC 200ma. and that the basic menu commands #701, 702 & 704 29.00 #301, 302 & 304 39.00 will look as I expect them to look Free article reprint with purchase. and be where I expect them to be. That standardization means that a Snooper Stopper 39.00 Macrovision Kit 29.00 total novice can do useful work with Cable TV descramblers can be Macrovision..now you see it, now an afternoon's training. I consult detected, protect your privacy you don't with our mecroscrubber documentation only when using with the Snooper Stopper kit. Article was published in Free article on Cable Snooping. Radio Electronics 1987 issue the more esoteric features of an application. Usually, the on-line help is CALL TOLL FREE 1-800-332-3557 more than sufficient. A great deal of Out side USA 1-508-699-6935 i the pleasure that I derive from work- Visa, Master Card and C.O.D. Visa M C ing with the Mac is in appreciation Add 13.50 S & H. $6.00 outside USA. of the elegance of the "overall archi- D & D Electronics, Inc., PO Box 3310, N Attleboro, Ma 02761 integrated tecture" of the entire CIRCLE 196 ON FREE INFORMATION CARD software/hardware system. I really don't understand the mix- ture of patronizing amusement and 1Aii %I i e grudging respect that the Mac com- CLEANING/MAINTENANCE/REPAIR The mands from DOS users. article EARN UP TO $1000 A WEEK,WORKING opens with a reference to "toys like PART TIME FROM YOUR OWN HOME! the early Macintosh"; later, it offers considerable praise for that "toy." I Secrets think that since the Mac is simple Revealed!

and fun to use, and DOS is demand- NO Special is Tools or ing of the user, that the Macintosh Equipment not taken seriously: "No pain, no Needed. gain."

I can attest to the Mac's power. I recently attended a seminar that demonstrated a new instrumenta- - tion software package called Lab THE MONEY MAKING OPPORTUNITY View. An application that fully OF THE 1990'S the standard Mac in- IF you are able to work with common small hand implemented tools, and are familiar with basic electronics (i.e. able terface communicated with an os- to use voltmeter, understand DC electronics)... . cilloscope,a microphone, a thermal IF you possess average mechanical ability, and have a VCR on which to practice and learn. ...then we can sensor, QuickBASIC, and the Excel teach YOU VCR maintenance and repair! spreadsheet-no surprises there. FACT: up to 90% of ALL VCR malfunctions are due to simple MECHANICAL or ELECTRO -MECHANICAL The bonus was in the interface: An breakdowns! on -screen image of a custom con- FACT: over 77 million VCRs in use today nationwide! Average VCR needs service or repair every 12 to 18 trol panel was drawn by the user, months! with toggle switches, slide controls, Viejo's 400 PAGE TRAINING MANUAL (over 500 photos and illustrations) and AWARD -WINNING VIDEO rotary knobs, etc. Those controls ac- TRAINING TAPE reveals the SECRETS of VCR mainte- tually operated the program. Data nance and repair-"real world" information that is NOT available elsewhere! was displayed in a user -designed Also includes all the info you'll need regarding the graphic format. What's more, not BUSINESS -SIDE of running a successful service operation! one line of code was typed! All pro- FREE INFORMATION gramming was done by selecting CALL TOLL-FREE 1-800-537-0589 Or write to: Viejo Publications Inc. 3540 Wilshire BL. STE. 310 Los Angeles, CA 90010 Dept. RE CIRCLE 179 ON FREE INFORMATION CARD www.americanradiohistory.com icons that represented e FRIENDLY VIDEOS N functions, hardware compatibility, etc. I feel devices, and subroutines, and safe buying a second-hand Mac be- 'The Pioneer In AT Clone Videos' drawing lines between them. Labels cause the probability that anyone and function parameters were has opened the case and touched COMPUTER typed. In the space of ten minutes, the hardware is very small. we had run data acquisition and As far as tinkering goes, if I want HOW-TO VIDEOS spectrum analysis on a sound sam- to modify hardware, I'll use an inex- ple, crunched a selection of the pensive "classic computer." If I want analysis in Excel, and displayed a to sit right down and get to work, I'll color bar chart. And the com- use the Mac. patibility was excellent. The seminar I'd like to build some stuff to at- i was conducted on Macintosh II's tach to my SCSI port, but hobbyists with large, high -resolution color and hackers are seriously ne- monitors. The demo disk ran equal- glected. It would be a great service ly well without any tinkering on a to a sizable (and growing) popula- low -end MacPlus. tion of users if Radio -Electronics Apple is thick-headed in its pric- would address that issue occasion- ing and marketing practices. The ally. Connectivity is a hot issue. Ex- Mac is not cheap, but it does avoid pand our horizons! "Video Tape Is A Great Teacher" the hidden costs associated with MICHAEL J. SCHENK open architecture-buying boards, Baltimore, MD `HOW TO BUILD YOUR OWN IBM 286/386 AT CLONE COMPUTER" Easy to do in a couple of evenings of work with just a screwd river. A real Do You Know the money-saver! ABC's 60 MINUTES VHS $39.95 of Home Theater? If you're looking to recreate the movie theater experience at home, home theater is just what you're looking for. The integration of large screen televisions, videodisc players, VCRs and surround sound processors is one of the most in SHAKE HANDS WITH YOUR PC/ exciting trends today's consumer electronics world. The following XT/AT COMPUTER`. A complete quiz will tell you how much you know about home theater. Score 10 points for each question new-user's hardware and software you answer correctly. learning guide. Everything from powering up, to the directory structure. 60 MINUTES VHS $29.95 1 . True or false: Only large screen 7. Videodisc players offer consumers two televisions can be used in home theater different formats: one with few special "HOW TO UPGRADE YOUR PC OR systems. effects, and another that allows such added XT COMPUTER TO AN AT FOR UN- features as frame search, freeze-frame. and DER $200". All in one evening with 2. Which of the following are types of multi -speed play. 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True or false: Surround sound decoders FREE OFFER! experience surround sound? must he incorporated in a home theater (a) A universal remote control system for the system to work properly. SAVE $40 NOW by ordering the complete set of all four (b) A surround sound processor titles at the ridiculously LOW PRICE of $100, and re- (c) Two extra speakers ceive, absolutely FREE, "After Hours" - 10. How many speakers are required for a software pro- (d) None gram to turn your PC into an unattended Message of the above ,urround sound? Center! (a) 2 5. Videodisc players that play all sizes of (b) 5 ORDER videodiscs and -compact discs are called (c) 4 VISA (a) All -in -one players (d) i NOW! (b) Multi -players (c) Continuation players (d) Combination players TOLL FREE: 1 -800 -PC -BUYER Service or CA, Call (714) a 6. What is television set without a tuner TN N that accepts input from such sources as a IT ON VCR, videodisc player, home computer. and a Friendly Videos RE07 THE video game? 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Only NRI walks you through the moving from the fundamentals to step-by-step assembly of a powerful sophisticated computer servicing AT -compatible computer system you techniques. Step by easy step, you keep-giving you the hands-on ex- get the kind of practical hands-on perience you need to work with, experience that makes you uniquely prepared to take advantage of troubleshoot, and service all of today's every opportunity in today's top- most widely used computer systems. You get growth field of computer service. all it takes to start a money -making career, even What's more-you learn at a business of your own in computer service. your own pace in your own home. No doubt about it: The best way to learn to service computers is to actually No classroom pressures, no night build a state-of-the-art computer from the keyboard on up. As you put the school, no need to quit your pre- machine together, performing key tests and demonstrations at each stage of sent job until you're ready to make your move. And all throughout your training, assembly, you see for yourself how each part of it works, what can go wrong, you have the full support of your personal NRI instructor and the NRI technical staff you need it. and how you can fix it. always ready to answer your questions and give you help whenever Only NRI-the leader in career -building, at-home electronics training for more Your FREE NRI catalog tells more than 75 years-gives you such practical, real -world computer servicing experience. Send today for your free full-color catalog describing every aspect of NRI's innovative Indeed, no other training-in school, on the job, anywhere- shows you how to computer training, as well as hands-on training in robotics, video/ audio servicing, troubleshoot and service computers like NRI. electronic music technology, security electronics, telecommunications, and other You get in -demand computer servicing skills as you growing high-tech career fields. train with your own AT -compatible system-now If the coupon is missing, write to NRI School of Electronics, McGraw-Hill with 20 meg hard drive Continuing Education Center, 4401 Connecticut Avenue, Washington, DC 20008. keep the powerful With NRI's exclusive hands-on training, you actually build and AT is a registered trademark of International Business Machines Corporation new AT -compatible West Coast 1010 ES computer, complete with 1 meg RAM and 20 meg hard disk drive. You start by assembling and testing the 101 -key "intelligent" keyboard, move onto test the circuitry on the main logic board, install the power supply and 1.2 meg School of For career courses 5 V4" floppy disk drive. then interface your high -resolution monitor. But that's not all. Electronics M/ 111 approved under GI bill 7 P:11 Only NRI gives you a top -rated micro with complete McGraw-Hill Continuing Education Center check for details training built into the assembly process 4.101 Connecticut Avenue, Washington, IX: 20108 Your NRI hands-on training continues as you install the powerful 20 megabyte hard Check one FREE catalog only to disk drive-today's most wanted computer peripheral-included in your course Computers and Microprocessors Security Electronics dramatically increase your computer's storage capacity while giving you lightning - Robotics Electronic Music Technology quick data access. TVNidco/Audio Servicing Basic Electronics Having fully assembled your West Coast 1010 ES, you take it through a complete Telecommunications series of diagnostic tests, mastering professional computer servicing techniques as you Computer Programming take command of the full power of your computer's high-speed 80286 microprocessor. In no time at all, you have the confidence and the know-how to work with, 'g, troubleshoot, and service every computer on the market today. Indeed you have Name (please print) what it takes to step into a full-time, money -making career as an industry technician, even start a computer service business of your own. Address No experience needed, NRI builds it in City/State/zip You need no previous experience in computers or electronics to succeed with NRI. Accredited Member, National Home Study Council 4219-070 , You start with the basics, following easy-to -read instructions and diagrams, quickly L

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excellent tool in electromechanical Tektronix 2214 and process -control applications, for which it was designed. Digital/Analog One of the interesting features Oscilloscope worth noting is that the scope can operate at a wide variety of speeds. A unique combination of Its roll mode can be used to slowly features makes this scope display up to 500 seconds of on- ideal for physical -system screen data. Such a display can measurements. often make the data easier to com- prehend. Alternately, the digitizer CIRCLE 28 ON FREE INFORMATION CARD can be clocked from an external source at any rate from DC to 8 MHz. WHAT DO YOU GET WHEN YOU CROSS A nector and its related parameter-se- The 2214's horizontal timebase is 20 -MHz, 4 -channel oscilloscope lection switches are also located on variable even in the storage mode. with four digitizers and an RS -232 the side panel. Waveforms-even frozen captured interface? You get the 2214 Digital/ signals, which consist of 16K data Analog oscilloscope from Tektronix Special features samples-can be expanded by up to (P.O. Box 500, Beaverton, OR 97077). The basic specifications of the a factor of 50 to let you zoom in for At first glance, the 2214 doesn't 2214 may not seem too impressive at close examination. All 16K sample appear any different from a standard first: an analog bandwidth of 20 points are visible on the screen in analog scope. The front -panel con- MHz, a bandwidth in digital -storage the expanded mode. All four chan- trols are laid out in an intuitively mode of 8 MHz. Such specifica- nels, and all 64K samples, can be easy -to -use format. Above each tions, however, tell only part of the displayed simultaneously. BNC input connector is its corre- story. The 2214 offers a number of You can freeze and store the sig- sponding input -coupling switch, at- features that make it stand out as an nals from any or all channels and tenuation selector or VOLTS/DIV switch, position control, and x 10 selector. To the right of the four vertical -amplifier controls are the time - base controls. The trigger controls are grouped together at the top right of the front panel, next to another group of controls for storage functions. The front -panel layout is kept un- cluttered in part by using a single push-button where you might expect more. For example, to select one of six possible trigger sources, a single push-button is used. Each time the button is pressed, a call -out above the button is back -lighted to indicate the choice. Connectors that are used less fre- quently are relegated to the side panel. They include external -trigger and Z-axis inputs, and a trigger -level output. The Z-axis input as doubles v an external -clock input when the scope is in its digital -storage mode. 0

The hardcopy serial interface con- Fig. 1

www.americanradiohistory.com ELENCO 8c HITACHI PRODUCTS AT DISCOUNT PRICES & From HITACHI Series Scopes RSOs (Real -Time Storage Oscilloscopes) A, Compact The RSO - its the new solution Delayed Sweep Test, Transfer Your Waveform Data ¡ N View, Acquire, and Document Lightweight (13lbs) 4 -Channel, 100MS/s Model Introductory Price 2mV Sens 100MS/5 (25MS/s on 4 Channels simultaneously), 100MHz, 4kw x 1ch., 2 K x 2ch., 1kw x 4ch. VC -6145 $ 4,695.00 3 Yr Warranty

Compact, Full Feature Models Model V-1065 40MS/s, 100MHz, 4kw x 1Ch., 2kw x 2ch. VC -6045 $ 3,049.00 Shown 20MS/s, 50MHz, 2kw x 2ch. VC -6025 $ 2,295.00 This series provides many new functions such as CRT Low Cost/High Value Models Readout, Cursor measurements (V-1085/1065/665), Ctr (V-1085), Sweeptime Autoranging and 20MS/s, 50MHz, 2kw x 2ch. VC -6024 $ 2,049.00 Frequency Trigger Lock using a 6 -inch CRT. You don't feel the 20MS/s, 20MHz, 2kw x 2ch. VC -6023 $1,749.00 compactness in terms of performance and operation. RSOs from Hitachi feature such functions as roll mode, averaging, save memory, smoothing, interpolation, pretriggering, cursor measurements, plotter interface, and RS -232C interlace. With the comfort of analog and the power of digital. V-660 60MHz Dual Trace $1,195 V-212 Hitachi Portable Scopes V-665 60MHz Dual Trace w/Cursor $1,345 V-1060 100MHz Dual Trace $1,425 $435 DC to 50MHz, 2 -Channel, DC offset function V-1065 100MHz Dual Trace w/Cursor $1,695 to 20MHz function, Alternate magnifier DC 100MHz Trace w/Cursor $2,045 Dual Channel V-525 CAT Readout, Cursor Meas. $1,025 V-1085 Quad V -1100A 100MHz Quad Trace w/Cursor $2,295 441111111111111.1100i wir V-523 Delayed Sweep $995 V-1150 150MHz Quad Trace w/Cursor $2,775 V-422 40MHz Dual Trace $795 V-522 Basic Model $895 20MHz Elenco Oscilloscope FREE DMM Elenco 35MHz Dual Trace $495 Good to 50MHz with $375 purchase of MO -1252 MO -1251 ANY SCOPE High luminance 6' CRT Dual Trace 1mV Sensitivity Component Tester SCOPE PROBES 6KV Acceleration Vohage 6' CRT 10ns Rise Time P-1 65MHz, lx, 10x $19.95 X -Y Operation Z Axis X -Y Operation TV 10x Delayed Triggering Sweep ,r, Sync P-2 100MHz, lx, $23.95 ..._ - ., s , .1i.$..-- Includes 2 P-1 Probes 2 p-1 Probes All scopes include probes, schematics, operators manual, and 3 year (2 yrs for Elenco scopes) world wide warranty on parts & labor. Many accessories available for all Hitachi scopes. Call or write for complete specifications on these and many other fine oscilloscopes.

WE NOW True RMS 4 1/2 10 Function Digital Capacitance Meter Digital LCR Meter CARRY Digit Muttimeter ! Multimeter CM -1550 LC-1801 LINE CM -365 COMPLETE M-7000 $58.95 111311 $125 OF $135 $65 9 Ranges Measures: .1 p1-20,000ufd Coils 1uH-200H FLUKE .05% DC Accuracy AC + DC Vohage & Amps .5% basic accy Caps .10-200uí .1% Resistance Resistance to 2000Mí1 MULTIMETERS Zero control Res .01-20M with Freq. Counter Diode, Logic, & Trans test with case 02211MISSOM Models and deluxe case Capacitance to 200uF 21F 83 23F 85 Function Generator Triple Power Supply XP -620 Wide Band Signal Generators 25F 87 Blox Assembled $65 SG -9000 27F 8050A -s-ar. .ï #9600 Kit $45 2 to 15V at 1A, $129 73 8060A $28.95 75 8062A -2to-15Vat1A RF Freq 100K-450MHz (or 4 to 30V at 1A) AM Modulation of 1KHz 77F + More Provides sine, triangle, square and 5V at 3A Variable RF output CALL FOR wave from 1Hz to 1MHz Contains all tie desired features for doing experiments. SPECIAL PRICING AM or FM capability Fe hures short circuit protection, all supplies. SG -9500 w Digital Display and 150MHz built -In Counter $249

A C Current Meterr Decade Blox Quad Power Supply XP -580 LEARN TO BUILD AND PROGRAM ST -1010 #9610 or $59.95 COMPUTERS WITH THIS KIT! INCLUDES: All Parts, Assembly and Lesson Manual $69.95 e #9620 2-20V at 2A .- 12V at lA Model $18.95 5V at 3A 1000 Amps MM -8000 #9610 Resistor Blox -5V at .5A Data & Peak hold 47 ohm to 1M & 100K pot 8 Functions $129.00 #9620 Capacitor Blox Fully regulated an short circuit protected Deluxe Case 47pf to 1OMFD XP -575 without meters $39.95 Digital Triple Power Supply XP -765 GF -8016 Function Generator with Freq. Counter Starting from scratch you build a complete system. Our Micro-Master $249 trainer teaches you to write into RAMs, ROMs and run a 8085 microproces- 0-20V at 1A $249 sor, which uses similar machine language as IBM PC. You will write the initial instructions to tell the 8085 processor to get started and store these 0-20V at 1A Sine, Square, Triangle instructions in permanent memory in a 2816 r PROM. Teaches you all 5V at 5A Pulse, Ramp, .2 to 2MHz about input and output ports, computer timers. Build your own keyboard Freq Counter .1 - 10MHz and learn how to scan keyboard and display. No previous computer Fuly regulated, Short circuit protected with knowledge required. Simple easy to understand instruction teaches you 2 limit control, 3 separate supplies to write in machine language. ROBOTICS KIT FOR ABOVE (MM -8010) $71.95 XP -660 with Analog Meters $175 GF -8015 without Freq. Meter $179 WE WILL NOT BE UNDERSOLD! 15 Day Money Back Guarantee C & S SALES INC. Prces subject to ch r,g, UPS Shipping: 48 States 59ó 1245 Rosewood, Deerfield, IL 60015 2 Year Warranty ($10 Max) IL Res., 7% Tax (810) 292-7711 (708) 541-0710 WRITE FOR FREE CATALOG

CIRCLE 109 ON FREE INFORMATION CARD

www.americanradiohistory.com New AOR can view both "live" and stored sig- Scanner nals at the same time. For example, 1000 Channels. a reference signal can be stored on 8-600MHz, screen while live inputs are 805-1300 monitored. MHz Any of the four input channels can serve as a trigger source, as can EARN YOUR a signal at the external trigger input. B.S.E.E. Positive- and negative -slope triggering is available, as is a "BiSlope" DEGREE mode that can obtain stable triggers for positive THROUGH HOME both and negative sig- STUDY nals. That's useful if you cannot pre- Continuous Our New and Highly Effective Advanced -Place- coverage dict the polarity ment Program for experienced Electronic Tech- fir(except UHF TV of signals you wish nicians grants credit for previous Schooling and 600-805) to acquire. The trigger level you se- Professional Experience, and can greatly re- AM, FM and wide band FM tuning modes. lect is available at an output jack duce the time required to complete Program and for 10 Scan Banks, 10 Search Banks reach graduation. No residence schooling re- Selectable Priority Channel. display on either a DMM or on one for qualified quired Electronic Technicians. *Selectable Search Increments, of the scope channels itself. Through this Special Program you can pull all of AR1000 5-955KHz the loose ends of your electronics background Total Rice, Freigt Permanent memory backup. together and earn your B.S.E.E. Degree. Up- (Express Sh)pp., vat) 25 Day Satisfaction Guarantee Hardcopy output grade your status and pay to the Engineering Full refund if not Satisfied No Frequencies Level. Advance Rapidly! Many finish in 12 cut out. An RS -232 interface is built into $499 All normal accessories included. months or less. Students and graduates in all 50 Size. 6 7/8"H x 13/4"D x 2 the 2214. You can output stored States and throughout the World. 1/2"W Established Wt. 12 oz Over 40 Years! Write for free Descriptive Lit- waveforms directly to plotters that erature. support the HPGL (Hewlett-Packard Graphics Language) or, alternatively, OOK'S INSTITUT: COMMUNICATIONS an Epson -compatible dot-matrix OF ELECTRONICS ENGINEERING 10701 E. 106th St. Indpls., IN 46256 printer. A sample printout is shown Toll Free 800-445-7717 CeE 4251 CYPRESS DRIVE Visa and Mastercard in Fig. 1. The printer can easily be E JACKSON, MISSISSIPPI 39212 (COD slightly higher) used to emulate a chart recorder. In FAX (317) 849-8794 CD that mode, acquired signals are con- CIRCLE 58 ON FREE INFORMATION CARD CIRCLE 195 ON FREE INFORMATION CARD tinuously output to the printer, resulting in a four -channel chart - recorder -like output. Speeds from Get A Complete Course In 10 s/cm to 2500 s/cm are available, making this mode ideal for recording transient events. ELECTRONIC Since the interface is RS -232 -compatible, you can, as you might ex- ENGINEERING pect, transfer data and waveforms to your PC. Waveform -transfer soft- 8 volumes, over 2000 pages, ware, Grabber II, is included with including all necessary math and the scope. Whether you order 1 part or physics. 29 examinations to help A flexible assortment of differen- all 23,477... MOUSER stocks you gauge your personal pro- tial measurement capabilities add to gress. A truly great learning . , . the value and can ship today experience. of the scope. Signals can SER also makes it e be inverted and added together to Prepare now to take advan- cancel unwanted common -mode do busin ```k` tage of the growing demand for noise and offsets. people able to work at the engineering level. The 2214 isn't a mass -market oscilloscope. If you're looking for a Ask for our brochure giving digital oscilloscope that offers the complete details of content. Use your free information card num- analog operation with which you're ber, or write us directly. $99.95, familiar, you'd be better served by Postage Included. Satisfaction one of the other, less expensive, guaranteed or money refunded. scopes in Tektronix's 2200 series. However, if you have special applications that require dual differen- 1\J U tial measurement capability, or if full Banner four -channel capability is important Technical to you, then the 2214 becomes the Books, Inc. obvious choice. The scope is priced at $3995, including the RS -232 inter- LECTR 1203 Grant Ave. Sales & Stocking Locations Nationwide - face, waveform -grabbing software, Rockford, IL 61103 N and two 10 x probes. R -E CIRCLE 20 CIRCLE 117 ON FREE INFORMATION CARD 67 ON FREE INFORMATION CARD

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ators, synthesizers, and sig- INDUSTRIAL SECURITY nal sources cannot graph- CAMERA. Small enough to ically create electrical wave- be hidden in a standard elec- forms. The R4010 also makes trical receptacle box, it easy to edit any digitized Chinon's CX-101 camera is real -world signal on a PC also versatile enough to screen and output the same meet a wide variety of securi- signal. Special features in- ty needs. Combining ultra - clude color waveform -crea- compactness, wide-angle tion software (with free viewing, and the ability to demo disk); 16,000 -point view even under near -dark waveform memory; continu- conditions, the CCTV cam- ous, sweep, and burst out- era can be positioned in put modes; programmable many locations, including output voltage to 10 volts p- doors. Suitable for industrial p; and a built-in library of or home security systems, it waveforms that includes features a 4.5mm lens with a sine, square, triangle, ramp, fixed iris and electronic shut- pulse, noise, and telephone ter that allows viewing in CIRCLE 11 ON FREE INFORMATION CARI) waves. such diverse locations as loading docks, stores, and vide light sensitivity as low as supply, and has an operating hotel or apartment lobbies. 2 lux-candle-light condi- temperature range of Measuring just 1'3Á,b x 23/4 x 1 tions-and sharp resolution 0-40°C. A metal housing with inches, and weighing only of 230 x 240 TV lines, or 1/4 -inch -20 mounting is also 6.3 ounces, the camera is 80,000 pixels. In addition, the available. easy to place for robotic vi- CX-101 runs composite video The CX-101 costs $550.- sion and inspection applica- leads, allowing direct cable Chinon America, Inc., Indus- tions in quality control, connection to a television trial Products Division, 1065 manufacturing, and produc- monitor. The camera re- Bristol Road, P.O. Box 1248, tion. Its fÁ1.8 lens and'/3-inch quires only 0.8 watts from a Mountainside, NJ CIRCLE 13 ON FREE MOS-type imaging chip pro - standard 12 -volt DC power 07092-1248; Tel. 201-654-0404. INFORMATION CARD

FREQUENCY COUNTER. De- equipment calibration. The R4010 waveform signed to provide an unusual The FC130A frequency creator/generator costs number of convenience fea- counter-complete with $2995.00.-Rapid Systems, tures and to operate over a power cord, operator's man- Inc., 433 North 34th Street, broad frequency range, ual, two BNC-to-alligator-clip Seattle, WA 98103; Tel. Beckman Industrial's FC130A test cables, and a spare 206-547-8311. microprocessor -controlled fuse-has a suggested list frequency counter measures price of $595.00.-Beckman frequency, period, and RPM Industrial Corporation, 3883 SOLDERING STATION. De- from 0.01 Hz to 1.3 GHz. Its Ruffin Road, San Diego, CA signed to meet hand -solder- standard features include 92123-1898; Tel. 619-495-3200. ing needs of the 1990's, The CIRCLE 12 ON FREE very high resolution (as low SA -570 Series soldering sta- INFORMATION CARD as 10 nHz fora 1 -Hz input); a tion from OK Industries pro- bright, 8 -digit LED frequency WAVEFORM GENERATOR. vides cost-effective flexibility readout with floating point to 120 MHz, and Channel B Rapid Systems' R4010 wave- and consistent performance. and overflow; 10 -mV input covers 50 MHz to 1.3 GHz. Its form -creation and -genera- Offering both durability and sensitivity (typical); continu- wide range, combined with tion instrument lets you use quick recovery, it features a ously variable gate time se- its heavy-duty design, makes a mouse to visually create powerful 70 -watt heating ele- lection; switchable AC or DC the FC130A suitable for both any waveform and then out- ment with precise RTD tem- coupling; a built-in self -diag- bench and field use in a vari- put the electrical waveform perature control that allows nosis routine; and a switcha- ety of applications ranging with a 10 -MHz, 12 -bit, arbi- excellent stability and re- ble x 20 input attenuator and from amateur and business trary waveform generator. peatability, as well as quick low-pass filter. Two separate radio, cordless -phone re- The advanced PC -based recovery on "heavy joints." channels are used to achieve pairs, and computer service. product easily accomplishes The SA -570 Series' operating high measurement ranges: The instrument can be used waveform creation and real- range of 600-800°F offers Channel A covers frequency in R&D, for troubleshooting ization functions where high power for a variety of measurements from 0.01 Hz and repair, and to check stand-alone function gener- applications, including on

www.americanradiohistory.com RAM-RESIDENT ELEC- transferred between directo- TRONIC MAIL. Offering the ries and from disk to disk distinct advantage of not re- without leaving the original quiring the user to leave his application program. Other application program, capabilities include printing Notework is a RAM -resident hard copies of any message, electronic -mail program that importing messages to text uses only 5K of RAM on each files in word-processing and PC. It allows users to pop up desktop -publishing pro- a note, file -transfer, or grams to keep a mail log, and phone -message form with- sending "Urgent" messages. CIRCLE 14 ON FREE out interrupting his work on The original installation disk INFORMATION CARD a word-processing or authorizes eight users; more spreadsheet program. Even users can be easily installed boards with exceptional non -technical users can with additional user -autho- CIRCLE 16 ON FREE thermal demands. Its di- learn to send, receive, and rization disks. INFORMATION CARD rectly grounded tip meets forward notes and phone The Notework eight -user MIL-STD -2000 resistance and messages right away, learn- installation disk costs ranges, from 10 Hz to 12 MHz voltage requirements. The ing as they go from the $495.00; additional 2-, 10-, and from 10 MHz to 2.4 GHz, soldering station's low -pro- Notework's menu. Note - and 50 -user authorization with 1 -Hz and 100 -Hz resolu- file, small -footprint housing work also allows screen sam- disks cost $99.00, $399.00, tion, respectively. The model takes up little bench space, ples to be attached to a and $1499.00, respectively. 2210-A personal frequency and the iron's light -weight message, and files to be Additional discounts are of- finder/counter's exceptional handpiece provides max- fered on larger networks.- range is accomplished by imum operator comfort and Professional Productivity Cor- using a unique input -pre - safety. The station uses high - poration, 72 Kent Street, scaling technique similar to mass soldering tips that are Brookline, MA 02146; Tel television -receiver design. available in a wide range of 1-800-767-6683. Rather than dividing the in- profiles. coming signal by a decade The SA -570 Series solder- RADIO -FREQUENCY FIND- number, the instrument di- ing station has a list price of ER. A handheld frequency vides it by 256, which ex- $86.90.-OK Industries, Inc., counter from Optoelectron- tends the upper range-and, 4 Executive Plaza, Yonkers, CIRCLE 15 ON FREE ics detects and displays two in the process, uses low-cost NY 10701; Tel .1-800-523-0667. INFORMATION CARD overlapping frequency TV parts. Because of the bin - THE HOUSE SITTER THAT DOESN'T NEED A KEY Use the keyboard to set Use the keyboard to emergency phone numbers, high ask for information and low temperatures, listen -in time and more SET key allows you ALERT/CANCEL key to change previous cancels automatic dial -out, settings allows you to answer phone SENSOR ON/OFF key chooses the functions WHAT IS key lets you to report listen to function settings and dial -out numbers ONLY $129.95 "This is 555-3210. Alert condition is OK. Temperature Dials Out In Alert Conditions is 65°. Electricity is on. Sound level is OK." Monitoring Set the unit to call out to your office, neighbors' and rela- your home from work or a vacation spot is made easy tives' to announce any alert conditions that are outside with the Heath/Zenith House Sitter Security Monitor/ preset limits. Up to four numbers can be programmed. Dialer. Order Toll Free 1-800-253-0570 Monitors Your Home The SD -6230 House Sitter is yours for only $129.95*. To When you call, the House Sitter will report on the AC order, call toll -free 1-800-253-0570. VISA, MasterCard, electric power, the room temperature - comparing it American Express or your Heath Revolving Charge card with high and low limits you've already set, loud noises accepted. Use order code 620-012 . such as burglar alarms and fire alarms , the unit's own battery backup condition, and an additional alert condi- See our full line of electronic products for tion. You can even listen to the sounds in the room your home in the Heathkit catalog - call 1 -800 -44 -HEATH for your FREE copy. Heath using the built in microphone. Benton Harbor, MI ©1990, Heath Company Subsidiary of Bull Data Systems, Inc. `price does not include shipping and handling, or applicable sales tan.

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www.americanradiohistory.com ary scheme, the internal time inches and weighs only 9 AC outlet. Electrical items base is referenced to a popu- ounces. that are plugged into the lar 3.90625 -MHz crystal, The model 2210-A hand- module can be controlled by which is the correct frequen- held frequency finder/coun- the transmitter from as far as cy to divide by 256. That ap- ter costs $219.00.-Op- 50 feet away. The 72-300 can proach reduces the prescaler toelectronics Inc., 5821 NE handle up to 1000 -watt loads time base to just four parts, 14th Avenue, Fort Lauder- and can be used to control and affords it a 10 -mV input dale, FL 33334; Tel. such things as televisions, sensitivity. At the low -fre- 800-327-5912 (in FL, lamps, stereos, appliances, quency range, the 2210-A 305-771-2050). fans, and most other elec- uses a 10 -MHz crystal and a trical appliances. It operates CIRCLE 18 ON FREE divide -by -decade technique on the UHF radio band and is INFORMATION CARD to get down to as low as sub - powered by an ordinary 9 - audio 10 Hz. volt battery. ments. The battery -powered Front -panel features in- The 72-300 remote AC unit, which weighs less than clude an eight -place LED dis- power switch system has a three pounds, provides play, range -select switch, suggested list price of 2H/2V MAG and 2H/2V power-select switch (exter- $39.95.-Midland Interna- sweep rates. It offers flat and nal 9-12 VDC or four re- tional Corporation, Consum- IRE filters as well as a 4 x ver- chargeable Ni -Cd batteries), er Communications Divi- tical magnifier that simplifies and a gate -control switch sion, 1690 North Topping, set-up level and black -bal- Kansas City, MO 64120; Tel. ance checks. Designed for and LED indicator for long or CIRCLE 17 ON FREE use with Leader's compact short sampling times. Avail- INFORMATION CARD 816-241-8500. able options include five dif- vectorscope (model 5854) ferent antennas, a probe for PORTABLE WAVEFORM and SID signal generator PC-board work, and a high - REMOTE AC -POWER CON- MONITOR. An upgraded (model LCG-413), the 5864-A accuracy time base for better TROL SYSTEM. A compact re- EFP/ENG waveform monitor is portable, rugged, and easy than ±1 -PPM accuracy. mote -control switch that can from Leader Instruments, to use. Housed in a high -impact alu- be used to turn on and off model 5864A, offers studio - The 5864-A portable wave- minum housing for years of any AC -powered device, quality monitoring for on -lo- form monitor costs durability and maximum Midland International's cation shooting, and the $1,395.00.-Leader Instru- EMI/RFI shielding, the fre- model 72-300, consists of a convenience of dual -input ments Corporation, 380 Oser quency finder measures an compact transmitter and a capability for signal com- Avenue, Hauppauge, NY easily portable 4 x 3'h x 1 small module that plugs an parison and timing adjust - 11788; Tel. 1-800-645-5104.

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www.americanradiohistory.com number, span, zero -suppres- model PM 2877, has a list sion, and chart speed-are price of $2340.00)-John printed on the chart output. Fluke Mfg. Co., Inc., P.O. Box User -defined text can also be 9090, Everett, WA 98026; Tel. added through the optional 800-443-5853, ext. 77. interfaces. The chart recorder accepts 8-1/2x11 and 11 x 17 -inch paper, as well as VACUUM FLUORESCENT Z -fold paper for continuous DIGITAL DASHBOARD. charts. It features automatic Breaking away from tradi- CIRCLE 20 ON FREE CIRCLE 19 ON FREE paper -edge detection and tional LED displays, Dakota INFORMATION CARD INFORMATION CARD sheet positioning and an op- Digital's vacuum -fluorescent tical pen -positioning system digital dashboard provides a tion even when the battery is for reliable operation. bright -blue fluorescent read- disconnected. Intended to ANALOG CHART RECORD- As an XY recorder, the PM outs with superior perfor- hobbyists, car buffs, and ER. Combining both XY and 8278 has 25 calibrated input mance and visual appeal. street -rod enthusiasts, the strip -chart modes, Fluke's ranges on both X and Y chan- The displays are readable in dashboard systems can be PM 8278 dual -pen analog nels, with a sensitivity range direct sunlight, and the sys- custom-built to virtually any chart recorder also adds dig- of 40 µV/cm to 2 V/cm. Fast tem automatically dims for user-specified arrangement, ital enhancements, such as dynamic response of 100 cm/ night-time driving. The and can be easily installed in built-in facilities for automat- s and 10-G acceleration en- dashboard uses a micro- any truck, car, or boat. ic chart annotation and pen - sure that even fast -changing processor system to mea- The vacuum -fluorescent offset compensation. Op- signals are accurately traced. sure, calculate, and display digital dashboard is available tional IEEE -488 or RS -232 in- In strip -chart mode, the re- speed, RPM, mileage, volt- as a complete set with alumi- terfaces are available for corder has 24 timebase set- age, oil pressure, water tem- num insert (as pictured) for complete remote control tings, including 10 user - perature, and fuel level. If a $499.95. Alternately, if you and data transfer in instru- programmable lines, varying reading should vary from send in your dashboard, the ment systems or for use as a from 10 mm/h to 120 mm/ normal limits, an "idiot light" display can be mounted in it hard -copy output device for min. Step response is 0.25 system causes the gauge dis- (without the aluminum in- a digital storage scope. seconds full scale. play to flash. A resettable sert) for approximately The PM 8278 is easy to use. The PM2878dual-pen ana- "trip meter" is included. Ve- $420.00.-Dakota Digital, At the push of one button, log chart recorder has a U.S. hicle mileage is stored in a 11301 Kuhle Drive, Sioux time, date, and instrument list price of $3360.00. (A sin- nonvolatile memory that Falls, SD 57107; Tel. settings-including channel gle -pen chart recorder, does not loose its informa - 1-800-852-3228. R-E EIK PRGA= Jlev MAXTEC INTERNATIONAL CORP. CABLE - TV SUMMER r SIGNAL UEMGVLI20 FOR ELIMINATION OF SEVERE INTERFERENCE FOR'CENSORING" OF ADULT BROADCASTS

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value of a current -limiting re- SOLDERING IRONS CATA- soldering irons and a wide sistor?-that knowledge be- LOG. M.M. Newman Corpo- selection of tips are featured comes a powerful skill that ration, 24 Tioga Way, P.O. Box in this 8 -page catalog. Ac- can be applied to designing 615, Marblehead, MA 01945; cessories for electronics as- and building your own cir- 617-631-7100; free. sembly, field service, and cuits. In his usual easy-go- general use are also ining, easy -to -understand cluded. In addition, the bro- style, the author takes the chure describes a heavy- mystery out of electronics by duty, 60-watt soldering iron; clearly explaining how all temperature -control sta- those laws and formulas re- tions; a universal power -sup- late to the real world, and ply unit; a portable, 12 -volt how you can put them to soldering iron; and a selec- JOSEF BERNARD work for you. tion of soldering -iron stands. CIRCLE 25 ON FREE Specifications for each type INFORMATION CARD 1990 FLUKE DISTRIBUTOR of iron are provided, along PRODUCTS CATALOG. John with a corresponding tip -se- THE ELECTRONIC PROJECT Fluke Mfg. Co., Inc., P.O. Box lection chart and illustrations BUILDER'S BOOK: DESIGN- 9090, Everett, WA 98206; of the various tip shapes, in- ING AND MODIFYING CIR- 1-800-443-5853; free. cluding spade, chisel, nee- CUITS; by Josef Bernard. TAB Featuring analog and dig- CIRCLE 27 ON FREE dle, pyramid, and hot -knife Books, Inc., Blue Ridge Sum- ital multimeters, digital ther- INFORMATION CARD tips. All kinds of soldering mit, PA 17294-0850; mometers, and multifunc- equipment is included, so 1-800-822-8158 (in PA and AK, tion counters, this 20 -page The complete line of Antex choosing the right iron for 717-794-2191); softcover; catalog also includes an ex- miniature and standard -size your next project is easy. R -E $14.95. panded section of new leads, If, like many electronics probes, and clips for a variety hobbyists, you've ever found of applications. The versatile yourself stumped-stuck at a Fluke 80 Series of handheld CRAMOLIN® DeOxidizer a multimeters, which offer a dead-end while building DEOXIDIZES CLEANS PRESERVES LUBRICATES IMPRA ES CONDUCTIVITY project, or unable to answer combination of measure- fold Metals, lncárourq Gold!' a deceptively simple ques- ment functions and special tion-and had no place to features for automotive, CRAMOLIN`'DeOxidizer...is a fast -acting turn for help, you'll appreci- electrical, and electronic test deoxidizing solution that cleans, preserves, and ate this book. In it, former applications, is highlighted. lubricates oll metal surfaces including gold. Radio -Electronics technical Also highlighted is the Fluke editor Joe Bernard has com- 45 dual -display multimeter, When applied to metal contacts, onnectors piled a treasury of practical which allows the user to and other metal surfaces, CRAMOLIN® advice and information that make two different measure- DeOxidizer removes resistive oxides and will go a long way toward ments of signal parameters forms o protective molecular layer that eliminating that kind of frus- simultaneously. adheres to metal surfaces, preventing future oxi- tration. Along the way, he dation. CRAMOLIN® DeOxidizer maintains gives you tips and pointers maximum electrical conductivity, reduces wear, and shows you how to de- and has excellent migration properties. sign, build, and trouble- 1990 CATALOG shoot your own, customized FLUKE DISC IUl4'Ka 111(0%X15 IDEAL FOR: Cables 8 Adaptors electronics projects. Switches R. Relays Connecting What sets this book apart Edge Connectors Terminal Stops Plugs R. Sockets from the crowd is that it Gold Plated Connectors Potentiometers Battery Contacts focuses not only on what to USED BY THOSE WHO DEMAND THE BEST; on why and how to do, but Bell 8 Howell Capitol Records Dolby Laboratories do it. A practical understand- Hewlett Packard John Fluke Mfg. McIntosh Labs

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book. When combined with Since 1956 the answers to dozens of c_ C commonly asked electronics r- questions-Why are there so CAlO Long lasting FREE LABORATORIES, INC. Economical/ many different kinds of tran- CIRCLE 26 ON Ozone Safe Propellents co Operates in Any Position O P 1 Esconddo, CA 920250051 sistors? How do I choose the INFORMATION CARD 0. Box Contents Completely Dispensed uniform Spray Pattern (619) 743-7143 FAX: (619) 743-2460 25 CIRCLE 50 ON FREE INFORMATION CARD www.americanradiohistory.com Join the Electronics and ,` INDUSTRIAL ELECTRONICS Control Engineers' ewe II,hdEdffl.^

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Packed with New Members! state-of-the-art cellular systems, from de- proven strategies for solving design and sign to implementation and troubleshoot- engineering problems and cutting your Take any one of these great ing. Clearly explains spectrum efficiency, clients' costs. propagation models and prediction, inter- 584657-8 Pub. Pr., $39.95 Club Pr., professional $31.50 ference treatment, and more. books 370/303 Pub. Pr., $62.95 Club Pr., $44.50 MCGRAW-HILL ENCYCLOPEDIA OF $289 ELECTRONICS AND COMPUTERS, for only TRANSFORMER Second Edition. S. Parker, Editor -in - AND INDUCTOR Chief. 1,047 pp., 1,250 illus. Featuring 160 as a premium with your DESIGN HANDBOOK, Second Edi- new and revised articles, this new edition tion. By Col. W.T. McLyman. 440 pp., treats the entire spectrum of applications, first selection! illus. 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Covers 360 x 9, pp., 6 illus., softcover 585390-6 the Circuit Cellar AT Computer to parallel design philosophy, PLD families, hard- A-to -Z coverage of all the essential interfacing and the Neighborhood Strate- ware, software, and programming lan- facts, figures, and formulas you need, gic Defense Initiative. guages. in a format that's easy to use and easy 109/699 Pub. Pr., $19.95 Club Pr., $15.95 585141-5 Pub. Pr., $29.95 Club Pr., $22.95 to carry. John Douglas -Young has filled this handy on-the-job companion A $33.00 THE COMPACT DISC: A Handbook with equations, algorithms, calculus of Theory and Use. By K. C. SURFACE -MOUNT TECHNOLOGY formulas, and BASIC programs in Value-Yours Pohlmann. 288 pp., illus. sottcover. The FOR PC BOARD DESIGN. By J.K. Hol- areas ranging from alternating current most readable and comprehensive guide lomon, Jr. 504 pp., illus., softcover. 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www.americanradiohistory.com INDUSTRIAL ELECTRONICS, Third DIGITAL FILTERS AND SIGNAL PRO- ANTENNA APPLICATIONS REFER- Be sure to Ed. By J.T. Humphries and L.P. Sheets. CESSING, Second Ed. By L.B. Jack- ENCE GUIDE. Edited by R. C. Johnson 651 pp., illus. A clear, convenient guide to son. 410 pp., illus. An acclaimed guide to and H. Jasik. 496 pp., 368 illus. and consider these the components and systems used in signal processing theory, design tables. Covers the major applications of important modern industry. Included is an extensive methods, and implementation strategies. antenna technology in all areas of commu- collection of manufacturers' data sheets, Using an intuitive approach, the author nications and their design methods. Em- titles as well! along with many quick -access tables and covers state -space representation, A/D phasizes important new applications such charts. and D/A conversion, the DFT, FFT, and as earth station, satellite, seeker, aircraft, BUCHSBAUM'S COMPLETE HANDBOOK 585226-8 Pub. Pr., $41.95 Club Pr., $31.95 much more. and microwave -relay antennas. OF PRACTICAL ELECTRONIC REFERENCE 585269-1 Pub. Pr., $52.50 Club Pr. $39.50 322/848 Pub. Pr., $59.95 Club Pr., $42.50 DATA, Third Ed. By W.H. Buchsbaum. Pr., BUILD YOUR OWN UNIVERSAL 583880-X Pub. Pr., $34.95 Club $26.50 COMPUTER INTERFACE. By B. SWITCHGEAR AND CONTROL RADIO HANDBOOK, Twenty -Third Ed. Edited by W. I. Orr. 667 pp., 1,073 ON-LINE ELECTRICAL TROUBLE- Chubb. 309 pp., illus., softcover. Guiding HANDBOOK, Second Ed. Edited by By L. Lundquist. illus. and tables. The latest edition of the SHOOTING. you from theory to step-by-step assembly R. W. Smeaton. 1,056 pp., 789 illus. The 391/106 Pub. Pr., $34.50 Club Pr., $26.50 most complete, current resource on radio instructions, this lively manual shows you only handbook that treats all aspects of technology and its applications. Expert CIRCUITS REFERENCE GUIDE. how to construct a computer interface and switchgear control, including design, ap- ESSENTIAL you how to select, de- By J. Markus & C. Weston. hook it up to virtually any IBM or IBM com- plications, safety, and maintenance. Up- contributors show sign, build, test and operate all kinds of 404/623 Pub. Pr., $59.95 Club Pr., $47.50 patible personal computer, including the dated to reflect the changes brought about XT, XT-286, AT, and System/2 Model 30. by the use of computers, solid-state equipment. Pub. Pr., Club Pr., 585080-X Pub. Pr., $19.95 Club Pr., $15.95 devices, and programmable controls. 584638-1 $29.95 $23.95 INTRODUCING PC -DOS AND MS-DOS, Second Ed. By T Sheldon. 584/494 Pub. Pr., $85.00 Club Pr., $59.95 AUDIO ENGINEERING HANDBOOK. 565/651 Pub. Pr.. $29.95 Club Pr., $19.95 Edited by K. B. Benson. 1056 pp., 722 il - lus. The ideal on-the-job reference for pro- ENGINEERING FUNDAMENTALS FOR THE fessionals who design, operate, and ser- PROFESSIONAL ENGINEERS' EXAM, Third a vice audio equipment. It s one -volume Ed. By L.M. Polenta. source of fundamental audio acoustics en- 503/931 Pub. Pr., $39.50 Club Pr., $27.95 Bl how-to 18CMC18P1811 gineering information and practical source book covering generation, trans- INTRODUCTION TO DIGITAL SIGNAL PRO- mission, storage, and reproduction of the CESSING. By J. G. Proakis and D. G. Manolakis. audio signal. 584954-2 Pub. Pr., $50.00 Club Pr., $37.50 047/774 Pub. Pr., $86.95 Club Pr., $59.95 AUTOMATIC CONTROL SYSTEMS, Fifth Ed. By B.C. Kuo. 583706-4 Pub. Pr., $57.40 Club Pr., $43.50

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Update your dashboard with sire accurate, gcoo-looping gauges. THE ELECTRONICS CONTENT OF TODAY'S automobiles is higher than ever before. Electronics can be found in ev- i' erything from the ignition sys-em to D SP the inst-ument cluster, commonly ROSS ORTVIAN called yur dashboard. That's what tells yot of your vehicle's performance, and warns you of pcssible probem=. However, some gauges are N simply not found on some cr dashooaxls, or there may be just an idiot ligtt, which, if your lucky, will warn you of a problem-but usually :i after a Froblem has occurred. If you }} 9,7 want to monitor certain functions, s / are a thenrelitble and accurate gauges . á 3 cc.r must. r gauges: rra_ntain constant engine tempera- TRti VHe'll look at six digital - %tNe" voltage, oil pressure, water temperature. Wi:icut a temperature gauge, ture, fuel level, vacuum, and er aux- toe first _ncicatián of an overheating iliary gauge for displaying any engine is usually the steam tiatcomes tempera3.Ire. be it outside air, inside from under toc hood, which often Creer air, transmission, oil, or whatever else too belated :c prevent engine damage. % 'J you wis-o to monitor. Next to The speedometer, the fuel 7", The digital voltmeter measures and gauge is orioao.y the most watched n The dig- displaysThe voltage level of the auto- instrumert tte dashboard. TRI mobile's. electrical system. The cor- ital fuel gain presented here displays rect voltage level is a good indication the level of fuel :eft it the tank on a of a heathy charging system ,which, kale of C to 9vao. in turn, will extend the life of the The digital vacuum gauge mea- battery. A failure in the autorrobile's sures the intake-rranifold vacuum in charginf. system can, of course, leave inches of mercury (in. Hg). Normal you straided. driving usually o-oduces a vacuum Proper oil pressure is very impor- reading tetweer. 16 and 22 in. Hg. monitor such things as the oil, trans- tant to :he operation of you- auto- The general raie of thumb is, the mission fluid, differen-ial fluid. etc. mobile'- engine. Without it, toe oil higher the a. uum level, the lower the In acdition to automo_ive operating would rot to pumped into bearings, gauge read -re. and the better the gas parameters, convenience items such journals, and over moving metal mileage. as outside air temperature and inside parts. The end result would be a As you. probably already know, an air temperature can also be seized er badly damaged engine. The automobile uses nrsny other fluids be- monitored. digital _il -Fressure gauge keeps you sides -he water and antifreeze in the informal as to how well your engine radiator. Aid, just like the coolant in Circuitry is being lubricated. the radiator, many of these fluids get A block diagram, which describes The digital water -temperature hot urder use. Siioe excessive heat- the circuitry that's common to all of gauge used to monitor the engine's ing irdica:es a potentially serious the gauges, is shown it Fig. 1 The coo_ingsystem, which is designed to problem, it is advantageous to central component of each digital

www.americanradiohistory.com gauge is the A/D converter. Because it mine the original input voltage level. Let's take a closer look at each indi- is common to all of the gauges, it The CA3161E has a differential in- vidual gauge. The gauges are very deserves a thorough explanation. The put which greatly simplifies circuit similar to each other, so we will not CA3162E A/D converter and the design. The full-scale input is 0.999 repeat descriptions for similar sec- CA3161E display driver form an accu- volts which results in a reading of tions. The same goes for the display rate, low-cost, three -digit analog to "999" on a three -digit display. The boards. digital converter system that can oper- resolution, or smallest change the A/

ate from a single 5 -volt supply. D converter can show, is 1 mV. Voltage gauge The basic operation of the A/D The CA3162E also controls the dis- The voltage gauge displays the volt- converter is based on the dual slope play multiplexing and updating. age of the automobile's electrical sys- system. Here, an integrating capaci- Using multiplexing, the parts count is tem on a three -digit readout with 0.1 - tor is charged to a level determined by greatly reduced, and, although only volt resolution. The gauge will dis- the input voltage. That is accom- one digit is lighted at a time, it ap- play voltages from 8 to 19.9 volts. plished by converting the input volt- pears that all the digits are on all the Because the input of the A/D convert- age to a relative current and using that time. er has a maximum input of 0.999 current to charge the integrating ca- The Binary Coded Decimal (BCD) volts, the input voltage to the meter pacitor for a predetermined time. output of the CA3162E is sent to the must be divided by 100. That way, the After that charge time, the voltage -to - CA3161E display decoder/driver, A/D's actual input voltage ranges current converter is removed and a which supplies segment current to from 0.080 to 0.199. That results in a current source of opposite polarity is each of the displays. Because the dis- reading of "080" to "199," and by connected to the capacitor. The time play driver contains internal current fixing the decimal point to the second required to discharge the capacitor to limiting, external current -limiting re- digit, a resulting display of "08.0" to its original value is measured to deter- sistors are not needed. "19.9" is obtained. The voltage gauge schematic is shown in Fig. 2. Power is supplied to +5 VOLT DIGITAL the voltmeter + 13.8V through Pl. The unit is REGULATOR ['ß+5V DISPLAY protected from excessive current by C fuse Fl. Diode D2 assists in protect- ing from reverse battery connection, and also clamps any momentary SENDER INPUT A/D DISPLAY negative spikes on the automobile's CIRCUIT CONVERTER DRIVER electrical system. Diode D2 allows only positive voltage to reach the 5 - MAIN BOARD DISPLAY BOARD volt regulator, ICI, that reduces the FIG. 1-BLOCK DIAGRAM COMMON to all of the gauges. The central component of each vehicle's 12 to 13.8 volts to the 5 -volt digital gauge is the A converter. level needed by the gauge's circuitry.

1 +13 8V 5V + - 5V 03 F1 2N3906 1A

DISP1 DISP2 DISP3 LN514RA LN514RA LN514RA CHASSIS 2N3906 10 1 10 10 GROUND 9 2 9 2 9

R15 D2 3 I I 8 100K .1N4002 - 5V + 5V 4 A R17 14 3 16 50K C6 ZERO 12 4 10 ADJ 33µF 9 4 5 11

8 7 14 IC2 2 ii IC1 CA3162E t 11 1 CA3161E 12 _L + 10 15 2 13 C4 10µF 6 16 » 6 15 13 7 8 9 4-R161K R11 1 10K R3 S 2200 DIGITAL GAIN VOLTMETER ADJ - MAIN BOARD (43821)LDISPLAY'BOARD (43815)

FIG. 2-THE DIGITAL VOLTAGE GAUGE displays the voltage level of your automobile's electrical system.

www.americanradiohistory.com voltage to ensure stable readings. A VOLTAGE GAUGE zero -adjust is provided by R17 and a OIL-PRESSURE GAUGE All resistors are 1/4 -watt, 5%, un- gain -adjust by R11. All resistors are 1/4 -watt, 5%, unless otherwise indicated. Once the input voltage has been less otherwise indicated. R1-R10, R12-R14-not used converted, its digital value is sent to R1-470 ohms R2-R8, R10, R12-R16-not used R11-10,000 ohms, PC -mounted section. There, ICI of the the display R9-100,000 ohms trimmer potentiometer display board receives multiplexed R15-100,000 ohms R11-10,000 ohms, PC -mounted BCD information and outputs that in- R16-1000 ohms trimmer potentiometer R17-50,000 ohms, PC -mounted formation to the three seven -segment R17-50,000 ohms, PC -mounted trimmer potentiometer displays, one at a time. The multi- trimmer potentiometer Capacitors plexing is controlled by IC2. Current Capacitors C1-47 µF, 25 volts, electrolytic to each display is switched by Q1, Q2, C1-47 µF, 25 volts, electrolytic C2, C5-10 p.F, 35 volts, electrolytic and Q3. For example, when Q1 is on, C2, C3, C4-10 µF, 35 volts, elec- C3, C4-not used current is delivered to DISPI, the trolytic C6-0.33 µF, 50 volts, stacked film most significant digit of the display. C5-not used C6-0.33 µF, 50 volts, stacked film Semiconductors To a the CA3162E display "138," Semiconductors 1C1-LM340T-5, 5 -volt regulator would send a binary 0001 to the IC2-CA3132E, A/D converter ICI-LM340T-5, 5 -volt regulator CA3161E, which would then turn on D1, D2 -1N4002 diode IC2-CA3132E, A/D converter Miscellaneous: 43821 main PC the necessary segments to display a D1, D2-1N4002 diode board, 3 -digit display board, in -line "1" on the first digit. After a predeter- Miscellaneous: 43821 main PC - fuse holder, 1 -amp fuse, four 6-32 mined time, the system moves on to board, 15G5 oil -pressure sender, 2 x 0.625" standoffs, eight 5/,s -inch the second and third digits and finally digit display board, in -line fuse #6 screws, bronze or red plex- repeats itself. Because the voltmeter is holder, 1 -amp fuse, four 6-32 x iglass, mounting hardware, hookup designed to display 0.1 -volt incre- 0.625" standoffs, eight 5/,s-inch #6 wire ments, the decimal point on DISP2 is screws, bronze or red plexiglass, hookup wire kept on all of the time by R3. A mounting hardware, Capacitors Cl and C2 help reduce "VOLTS" annunciator is formed by voltage transients and fluctuations. LED1, which is a pre -formed module from 0 to 80 psi (pounds per square The A/D converter (IC2) converts containing two LED's, and limiting inch) with 1 -psi resolution. The inpu the input voltage to a relative digital resistors R1 and R2. The module has a voltage to the A/D converter mus value, and C6 is the integrating capac- plastic "lens" over it that is all black therefore range from 0 to 0.80 volts itor that was discussed earlier. A di- except for the clear letters V-O -L-T -S. The oil pressure is sensed by the oil vide -by-100 network, that provides pressure sending unit which convert the proper input voltage for the A/D Oil pressure pressure to electrical resistance. Il converter, is formed by R15 and R16. The oil -pressure gauge, shown in the case of the sending unit used here Capacitor C4 filters the A/D input Fig. 3, displays engine oil pressure pressure is converted to resistanc

+ 5V 4 + 5V 02 F1 D1 2N3906 lA IN4002 LM340T-5 +13.8V Pt 5V » DISPI DISP2 /7771 0.1 LN514RA LN514RA CHASSIS 2N3906 10 1 10 GROUND Cl C2 D2 = 47µF 10µF 2 9 2 9 Jr; R1 IN 4002 47011 3 I I 8

+ 5V + 5V

R17 14 16 50K C6?. 10 ZERO 12 3 4 ADJ .33µF -->i'- 9 4 11

8 14 IC2 2 » 7 ICI 11 CA3161E 12 We CA3162E v»2 13 R9 10 15

100K 6 16 6 15

C3 C4 13 7 8 9 10µf 10µF - R11 I - 10K MAIN BOARD i GAIN ADJ OIL PRESSURE (43B21) DISPLAY BOARD (43816) L a

FIG. 3-THE OIL -PRESSURE GAUGE displays engine oil pressure from 0 to 80 psi with 1 - psi resolution.

www.americanradiohistory.com with an approximate 1:1 ratio. That is, ature sending unit, which is essen- with 60 pounds of oil pressure, the tiality a thermistor contained in a WATER -TEMPERATURE GAUGE sender's resistance is approximately brass enclosure. Because the sending All resistors are'/4-watt, 5%, unless 60 ohms, with a 0.6 -volt drop across unit's resistance is inversely propor- otherwise indicated. R1-100 ohms, 1/2 -watt it. With no oil pressure, the sender's tional to temperature (the greater the R2-430,000 ohms resistance is zero ohms. The voltage temperature, the lower the resis- R3, R7-10,000 ohms, PC -mounted drop across the sending unit is then tance), the differential input of the A/ trimmer potentiometer filtered and read directly by the A/D D converter is used. That means that R4, R8-22,000 ohms converter. The regulator and A/D con- the A/D converter CA3161E measures R5, R9, R11-R16-not used verter sections are similar to the volt- the difference between its positive R6-470,000 ohms meter, and the display section is and negative inputs (pins 1 and 10, R10-2200 ohms identical except for one less digit. respectively). R17-50,000 ohms, PC -mounted The sending unit and R1 on the A reference voltage, set by R6, R7. trimmer potentiometer main board form a resistive divider. and R8 is applied to the positive input Capacitors C1-47 µF, 25 volts, electrolytic The voltage drop across the sending at pin 11. The negative input (pin 10) C2, C5-10 µF, 35 volts, electrolytic unit equates is to 0.01 volt/psi. That is, connected to the temperature -send- C3, C4-not used for every psi of oil pressure, the volt- ing unit via a resistor network. As the C6-0.33 µF, 50 volts, stacked film age across the sender increases by ap- temperature of the sending unit in- Semiconductors proximately 10 millivolts. The relative creases, its resistance will decrease, D1, D2 -1N4002 diode voltage across the sender is then fil- lowering the voltage across it. When IC1-LM340T-5, 5 -volt regulator tered by C3, R9, and C4 to maintain a the lower voltage is seen at the nega- IC2-CA3132E, A/D converter more stable reading. An "OIL" an- tive input of the A/D converter, and Miscellaneous: 43B21 main PC nunciator (LEDI) specifies the read- compared to the level set at the board, 14G11 water-temperature ing of the gauge. positive input, the temperature read- sender, 3 -digit display board, in - line fuse holder, 1 -amp fuse, four ing will rise. The opposite happens as 6-32 x 0.625" standoffs, eight 6/16 - Water the sending unit cools; its resistance inch #6 screws, bronze or red plex- The water-temperature gauge, becomes greater and more voltage is iglass, mounting hardware, hookup shown in Fig. 4, displays the auto- applied to the negative input. The wire. mobile's coolant-system temperature temperature reading then decreases as

on a three -digit readout with 1 -degree the negative input gets closer in po- resolution. The actual temperature is tential to the positive input. A reading the negative input is limited to a max- obtained by measuring the resistance of 0 will result when the positive and imum of 1.2 volts. across a standard automotive temper- negative inputs are equal. Note that The regulator and display sections

+13.8V +SV+ - + 5V Q3 F1 01 2N3906 IA 1N4002

Q2 DISP1 DISP2 DISP3 )77 )f 2N3906 LN514RA LN514RA LN514RA CHASSIS 1 10 D2 Cl C2 10 10 GROUND 47µF 1DµF IN4002 2 9 2 2 R8 R7 R6 3 I 4700 1K = 6.8K 18 8 5V Q1 WW1- A/1 7 7 OW + 5V 2N3906 * 5V ADJ 6 A 817 14 5V 5 16 50K R13 ZERO C6 .r12 3 4 10 1K ADJ .33µF 9 4 11 R14 8 IC2 2 7 IC1 2205! 14 CA3162E CA3161E R12. 11 1 12

e10K 10 5 2 13

C5 i+ R11 6 16 6 15 10µF 10K » 13 7 8 9 -s R5 HIGH 22K ADJ LEDI P2 ; COAX DIODE TEMP PROBE CABLE 1N4148 LMISCELLANEOUS TEMP MAIN BOARD (43821) DISPLAY BOARD (431315/

FIG. 4-THE WATER -TEMPERATURE GAUGE displays the automobile's coolant -system temperature on a three -digit readout with 1 -degree resolution.

www.americanradiohistory.com r

F1 D1 5V +13.8V 1A IN 4002 02 C11j> -» -1>f- I 5V 2N3906 P1 CHASSIS Cl GROUND -Jr D2 T47µF IN40O2 DISP1 DISP2 LN514RA LN514RA R10 EMPTY lOJ RANGE 1 10 10OK ADJ (B) -wh- A: EMPTY 0-20 OHMS 9 2 R19 01 2 9 FULL 15-240 OHMS R13 100K 2N39O6 3 R2 B: EMPTY 60-300 OHMS 6.2K 2 10013 FULL 0-35 OHMS 7 14 3 +.SV + 5V 12 R14 + 5V IC2-d IC2-a ` R21 16 10OK A LM324 114 /< LM324 50K 3 ZERO C4.T.12 » 10 - R15 10µF 9 33K ADJ 4 11 100K R8 >> - 8 2 7 14 10K IC3 » ICI Bó o- FULL Rtt 11 CA3162E 1 CA161E 12 ADJ Ws. » í8)'27K Aôo- 10 15 2 13 R20 » 47OK 6 16 6 15 C3 + » 13 7 9 R4 10).LF FULL R9 47K ADJ 200K 5V R12 R16 9 IA) 2.222K 100K IVY 811w; 5V C2 -c - R5 LM324 7 100K R6 5Vf V1h J ¡( IC2-b -5V 1.8 MEG R17 1/4 LM324 22K -.1- R18 LEDI R7 - 1K 100K EMPTY ADJ (A1 SENDING UNIT 5V. 1__« t R1 P2 COAX et /7777 4700 y K< CABLE FUEL LEVEL = MAIN BOARD (43B20) DISPLAY BOARD (43616)

FIG. 5-THE FUEL GAUGE displays the level of fuel in your gas tank on a two -digit readout, which is interpreted as percentage of the fuel remaining. are again similar to that of the volt- preted as percentage of the fuel re- voltage developed across the sending meter's. Looking at the A/D convert- maining. The fuel gauge senses the unit proportional to the fuel level. For er's input circuitry, note that R1 and resistance of the fuel sending unit lo- sending units that increase in resis- the temperature sending unit form a cated in the gas tank. Typical sending tance as the tank is filled, the R5 path resistive divider network with the units consist of a potentiometer with is taken. Because the voltage in- sending unit connected through P2. its wiper connected to a float. As the creases as the fuel level rises, we off- The relative voltage at that point is fuel level rises and falls, the resistance set the empty reading and adjust the then divided down by R2, R3, and of the potentiometer changes. Al- top scale for a "full" reading. R4. Potentiometer R3 provides the though sending units are not com- Because the gauge works from a low -temperature calibration adjust- pletely linear, due in part to the single supply, and the A/D compares ment, and C5 filters the input voltage irregular shape of most gas tanks, its positive input to its negative, we for stable readings. That voltage is their output resistance does go con- need to be able to reach zero volts in then sent to the negative input of the sistently from low to high. Some order to display a zero (0% fuel left). A/D converter, 1C2. Resistors R6, sending units have a high resistance Most op -amps will work very close to R7, and R8 form a resistive divider when empty and a low resistance their negative supply, which in this that sets the upper reference voltage, when full, as with most Ford, AMC, case is ground, but not completely. the high -temperature calibration is set marine, and aftermarket senders, and By biasing the negative input of the by R7, and the A/D converter zero some go from a low resistance when A/D converter to 0.21 volts, the adjust is set by RI7. A "WATER" empty to a high resistance when full, ground reference for the op -amp annunciator is formed using LED1, as is the case with most GM sending "zero" level becomes 0.21 volts. The

R I , and R2. units. By having two range settings, op -amp output can then easily reach the fuel gauge can handle both kinds the "ground" reference level to obtain Fuel of sending units. The range settings a "00" on the display. All other volt- The fuel gauge displays the level of (A and B) are shown in Fig. 5. age values are then referenced to the fuel in your gas tank on a two -digit Current for the sending unit is de- 0.21 volt "ground." Potentiometer readout (see Fig. 5). The readout's rived from Rl, which forms a voltage R7, along with R6, is used to offset range is from 0 to 99, and is inter- divider with the sending unit. The the output of IC2 (pin 8) to 0.21 volts.

www.americanradiohistory.com +13.8V , + 5V « + 5V

F1 lA

» Q2 DISP1 DISP2 DIS P3 0.1 2N3906 LN514RA LN514RA LN514RA

CHASSIS 1 D2 Cl 2N3906 10 1 10 1 10 GROUND IN4002 47µF 2 9 2 9 R8 R7 = R6 22K 10K 470K I 1 I8 HIGH ADJ +5V + 5V 45V 5V I 6

R17 14 5 16 R1 50K C6 10 100 ZERO 1/2W ADJ 11

14 R2 ICI

430K 1 CA3161E 12 LOW ADJ R3 2 13 10K 6 15 R4 22K 9

< P2 COAX LED1 CABLE < TEMPERATURE I SENDING -L UNIT

`WATER TEMP MAIN BOARD (43B21)ß DISPLAY BOARD 1438151

FIG. 6-THE MISCELLANEOUS TEMPERATURE GAUGE displays temperature by measuring the voltage drop across a typical silicon diode.

After the zero offset is adjusted, the jumper in the "A' position. way, after passing through R2 and an next step is to adjust for the "full" When using a sending unit that de- inverting amplifier, the higher send- reading. That is accomplished by creases in resistance as the tank is ing -unit voltage from an "empty" changing the gain of IC2, by placing a filled, the "B'' juniper is used. That continued on f)QL,'e 40

F1 01

+13.0V IN4002 ICI 1,÷11 LM340T-5 5V

CHASSIS II » C2 C j GROUND re77 = 47µF 10µF D2 7 DISP1 DISP2 13 IN4002 IC2-d LN514RA LN514RA YaLM324 14 /V1r 10 1 10 5V R1 R6 137 2 2 9 RB = 10K 680K 200K ' SENSYMM e 100K 1 SX30DN 16

5V I- 5V 21 IC2-a ClI R2 .4 /, LM324 R11 14 5 16 L__ 10K R3 50K 100K ZERO C4 T12 3 4 10 33µF >>- R9 ADJ 4 11 82K >> 8 8_ IC4 2 7 ICI 14 10 ÌC2 -c CA3162E » CA3161E " LM324 11 1 » 5V C3010 -Z 10 5 2 + 5V 20OK 101F R1 R2 + 5V ,e 6 6 6 R4 GAIN 2000 2200 R5 22K 4 13 9 1K 7 1 V1h IC2-bR12 LEM 11 '/A LM324 2.2K `ACUUM MAIN BOARD (43B171 = DISPLAY BOARD (431 B6) 1

FIG. 7-THE VACUUM GAUGE uses a Sensym SX3ODN solid-state vacuum/pressure sensor to monitor the intake -manifold vacuum during engine operation. Between 0 and 30 inches of mercury can be displayed.

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www.americanradiohistory.com voltage across the diode is scaled ac- divider network consisting of R12 and Note: The following items are cordingly. The temperature is then RS. That second divider scales the available from Dakota Digital, displayed on a three -digit readout relative voltage developed across the 11301 Kuhle Drive, Sioux Falls, with 1 -degree resolution. temperature probe to coincide with SD 57107 (605) 332-6513: a PC - Because the voltage across the di- the range of the A/D converter. It is board set for each gauge (in- ode is inversely proportional to tem- also used to bias the temperature -pro- cludes main PC board and dis- perature, the differential input of the be play board) is $6.95. A parts kit diode. For example, suppose the for each gauge (includes PC A/D converter is used in the same voltage across the diode at 32 degrees boards, components, and man- manner as the water-temperature Fahrenheit is 0.6 volts. Then, 0.654 ual) is $29.95. Each gauge as- gauge. Note that the positive input at volts would be delivered to the nega- sembled and tested is $39.95. pin 11 is connected only to a reference tive input of the A/D converter. With Stock numbers are as follows: voltage set by R6, R7, and R8. The the positive input of the A/D convert- voltage -gauge kit #2005 -KIT, as- negative input (pin 10) is connected to er calibrated to 0.686 volts, "032" sembled and tested #3005 - the 1N4148 diode temperature probe would be displayed on the digital UNIT; oil -pressure gauge kit via a resistor network. As the temper- readout. As the temperature -probe di- #2006 -KIT, assembled and test- ature of the diode increases, the volt- ode heats to 212 degrees Fahrenheit, ed #3006 -UNIT (order oil -pres- age across it will decrease resulting in the drop is reduced to volts. We sure sender separately); water - 0.4 a lower voltage at temperature gauge kit #2007 - the negative input of would now have 0.49 volts at the KIT, assembled and tested the A/D converter and, when com- negative A/D converter input. The #3007 -UNIT (order water -tem- pared to the level set at the positive display will now read "212." perature sender separately); Although the negative input is not a miscellaneous temperature FUEL GAUGE gauge kit #2008 -KIT, assembled All resistors are'/4-watt, 5%, un- MISCELLANEOUS and tested #3008 -UNIT; fuel - less otherwise indicated. TEMPERATURE GAUGE gauge kit #2009 -KIT, assembled R1-470 ohms All resistors are 1/4 -watt, 5%, un- and tested #3009 -UNIT; vac- R2, R5, R10, R12, R14, R15, R16- less otherwise indicated. uum -gauge kit #2010 -KIT, as- 100,000 ohms R1 -R4, R9, R10, R15, R16 -not used sembled and tested #3010 -UNIT R3-33,000 ohms R5-2200 ohms (order vacuum sensor sepa- R4-47,000 ohms R6-6800 ohms rately). Oil -pressure sender R6-1.8 megohms R7-1000 ohms, PC -mounted trim- (#15G5), $15.50; water -tempera- R7, R19-100,000 ohms, PC - mer potentiometer ture sender (#14G11), $5.50; vac- mounted trimmer potentiometer R8-470 ohms uum sensor (#69G18), $19.95; R8-10,000 ohms, PC -mounted R11-10,000 ohms, PC -mounted RCA CA3161E driver (#69G16), trimmer potentiometer trimmer potentiometer $1.95; RCA CA3162 A/D convert- R9-200,000 ohms, PC -mounted R12-10,000 ohms er (#69G15), $7.95. All orders trimmer potentiometer R13-1000 ohms add 4% shipping and handling R11-2700 ohms R14-220 ohms ($1.50. minimum), Visa and Mas- R13-8200 ohms R17-50,000 ohms, PC -mounted tercard accepted. R17-22,000 ohms trimmer potentiometer R18-1000 ohms Capacitors R20-470,000 ohms C1-47 µF, 25 volts, electrolytic reading is offset by R8 to produce an R21-50,000 ohms, PC -mounted C2, C5-10 µF, 35 volts, electrolytic at 14 output pin of IC2 that is near trimmer potentiometer C3, C4 -not used 0.41 volts. Divided down to 0.21 volts R22-2200 ohms C6-0.33 µF, 50 volts, stacked film by R14 and R15, the output at pin 1 of Capacitors Semiconductors IC2 is at the proper 0.21 -volt zero C1-47 µF, 25 volts, electrolytic ICI-LM340T-5, 5 -volt regulator reference. The "empty" voltage is ad- C2, C3-10 µF, 35 volts, electrolytic IC2-CA3132E, ND converter justed by R19. Components R20 and C4-0.33 µF, 50 volts, stacked film D1, D2 -1N4002 diode C3 are used to average the input volt- Semiconductors Miscellaneous: 43B21 main PC age to avoid erratic readings caused IC1-LM340T-5, 5-volt regulator board, 1N4148 diode for tempera- by the sloshing of gasoline in the fuel IC2-LM324, quad op -amp ture probe, 3 -digit display board, IC3-CA3132E, A/D coax cable, in -line fuse holder, l- tank. The zero adjustment of the A/D converter D1, D2 -1N4002 diode amp fuse, four 6-32 x 0.625" converter is set by R17, and LEDI, Miscellaneous: 43B20 main PC standoffs, eight 5/16 -inch #6 with an appropriate lens, is used as a board, 2 -digit display board, 0.1" 3 - screws, bronze or red plexiglass, "FUEL" annunciator. conductor header, 2 -conductor mounting hardware, hookup wire. jumper, in -line fuse holder, 1 -amp Temperature fuse, four 6-32 x 0.625" standoffs, full 180 millivolts lower than at 32 The miscellaneous temperature eight 5/16 -inch #6 screws, bronze or degrees, the gain control of the A/D gauge, shown in Fig. 6, displays tem- red plexiglass, mounting hardware, converter compensates for that. The perature by measuring the voltage hookup wire. compensation also allows the con- drop across a typical silicon diode, verter to have an adjustment window which is determined by the formula input, the reading will rise. Just the so tolerance effects can be calibrated V1) = 2mV per degree Celsius, where opposite happens as the diode cools. out. Looking at the remaining circuit- V1) is the voltage drop. Because the Resistors R13 and RI4 form a volt- ry, C5 is used to filter the input voltage temperature gauge is calibrated to age -divider network that provides a for stable readings. Resistors R6, R7, read out in degrees Fahrenheit, the reference of 0.9 volts for the second continued on page 6/ 40

www.americanradiohistory.com THERE ARE SEVERAL WAYS TO CAPTURE DALE B. BLACKWELL and listen to sounds at a distance. Obviously, you could always set microphones at a location of interest, and transmit the sounds by wire or radio to your position. However, that's A novel not always convenient or practical in super -directional certain cases of surveillance, or when microphone that dealing with bird calls or animal many sounds. outperforms Another option is to use a sensitive, costly commercial directional microphone similar to designs. those used in network TV broadcasts of football or other sporting events. Such microphones typically have parabolic reflectors for focusing sound onto them. The microphone we'll describe here uses a different approach, yet is perfect for long-distance monitoring or surveillance.

Theory The major criteria that determine microphone performance are direc- SUPER tional sensitivity and frequency response (bandwidth). Just as frequency response and directional sensitivity in antennas are changed by varying the DIRECTIONAL lengths, diameters, and relative angles of metal radiators or reflectors, the analogous characteristics of microphones can be adjusted by similar MICROPHONE geometric variations. One lesser known antenna type, normally used in microwave applications, is the horn like fashion, acoustic energy also ex- ciprocity, which lets a microphone antenna. The horn microphone pre- hibits the same phenomena. Just as work equally well as a loudspeaker of sented in this article is designed using antennas are electromagnetic lenses, identical design, both directionally analogous principles which could, in- so too are microphones and loud- and in frequency response; this prop- cidentally, also be applied with equal speakers acoustic lenses. erty also holds true for antennas. validity to the design of a loud- Not only are microphones and speaker, for reasons discussed below. loudspeakers acoustic transducers or Different microphone types A very helpful concept in either lenses, but also acoustic filters. Just as Most microphones are omnidirec- acoustic or electromagnetic design is all filters have frequency and phase tional, as shown in Fig. 1. Figure 1-a to think of a microphone, loud- response, so too do microphones and shows the basic shape of an om- speaker, or antenna, as just a trans- loudspeakers. However, here, as with nidirectional microphone with the ducer. This concept can be extended antennas, two types of filtering occur: main axis, while Fig. l -b shows a still further, if you consider a trans- directional and frequency. linear polar plot of relative sensitivity ducer of wave -propagated energy that Another term for directional sen- P(0) (dynes/cm2) as a function of an- focuses such energy onto a receptor to sitivity is directivity, often a desirable gle 0 about the main axis; all curves be a lens. Consider the similarities, trait, since it prevents spurious sound are normalized to 1 at the peak of the taking the antenna first, since it's the from entering from undesired direc- main beam. The main beam can be at more obvious. Both antennas and tions. A microphone with uniform di- any angle, although it's normally de- lenses focus and collect electromag- rectivity is termed omnidirectional; picted at 0°. If several people sit netic energy, the only difference however, flat directional response around a table, an omnidirectional being that light is at a much higher doesn't imply flat frequency re- microphone at the center will pick frequency range, and obeys the laws sponse. A microphone can either have them all up equally well. Any plane of optics. (Actually, microwave an- a flat response over the audio spec- that passes through the main axis will tennas also exhibit quasi -optical trum (20 Hz -20 kHz), or be tailored exhibit this sensitivity response. physical phenomena.) for greater sensitivity over specific au- The second most common micro- Consider for a moment; don't both dio bands. The acoustic horn pre- phone type is the cardioid, shown in electromagnetic radiation and light sented here has very high directivity Fig. 2-a, which has greater directivity exhibit the same phenomena of reflec- over the entire audio spectrum. toward the front over most of the audio tion, refraction, absorption or at- The last property microphones and range. The sensitivity pattern shown tenuation, and polarization? And in speakers have in common is re- in Fig. 2-b looks like the mathemati-

www.americanradiohistory.com from the audience. The power function is of the form: INCIDENT SOUND P(0) = Pref[1 + cos(0)], = 2 x PrefCOS2(0/2). MICROPHONE 3 At 0 = 0°, the sensitivity is max- a 180 imized. The sensitivity goes to zero (a null) at 0 =180°. REFLECTOR ICROSS SECT ONAL VIEW The ribbon element microphone OF PARABOLIC REFLECTOR) shown in Fig. 3-a is the industry standard, well-known from all the photos of radio stars in front of them. It's 200 Hz 1 kHz 8 kHz sensitive from both front and rear, producing the figure -8 pattern shown in Fig. 3-b. A microphone that picks up well equally in opposite directions FIG. 4-THE DIRECTIVITY OF A parabolic is advantageous in a talk show where reflector microphone increases with fre- the guest sits opposite the host. quency. In (a), the incident parallel rays converge to the microphone at the focal point. In (b) are shown linear polar plots of acoustic power at four frequencies. HIGH AUDIO FREQUENCIES 180° 180 b phone; all parallel rays, wherever they FIG. 1-AN OMNIDIRECTIONAL micro- strike the curve, are reflected to the phone, shown in (a), has uniform direc- focal point, where the microphone is tional sensitivity to sound pressure P(0); the main axis is out the indicated. In (b) is located. Parabolic microphones are shown a polar plot of directional sen- also especially directive at higher au- sitivity; the response is identical in any dio frequencies, as shown in the sen- plane through the main axis. sitivity patterns of Fig. 4-b. As shown in Fig. 5-a, the line (shotgun) microphone is 180° another commercial directive version, albeit not quite as focused as a parabolic reflector. The line microphone has either a single long tube with spaced openings, or several tubes of increasing length, in front of the microphone element. The sensitivity patterns in 00 Fig. 5-b aren't for differing frequencies, but for different tube lengths, being integral multiples of X/2, or half a wavelength.

LENGTH OF OPENINGS

o 180°

180° R b MICROPHONE b a ELEMENT FIG. BIDIRECTIONAL microphone, 3-A TUBE A FIG. 2-A CARDIOID MICROPHONE, shown in (a), is uniformly sensitive to TUBE TUBE 8X LENGTH 2 LENGTH LENGTH shown in (a), has greater sensitivity from sound from front and rear, but less sen- the front than the rear. The 0` and 180' sitive from the side; the main axis is the directions are along its main axis, point- same as that for a cardioid microphone. ing through the main face. The sound Note, however, that P(H) in (b) has two pressure sensitivity P(0) shown in (b) was lobes, not one, with two maxima and two taken through a plane normal to the main minima (zeros, or nulls). b axis. FIG. 5-A LINE (SHOTGUN) microphone Increasing directivity becomes more directive as the length of cal curve called a cardioid (heart - Experimenting with basic micro- its tubes increase. It's not as directive as a shaped), hence the name. An or- phone directivity patterns yield more parabolic reflector, and either has one chestra in a night club might use a specialized designs that are much long tube with spaced openings, or several tubes of increasing length each with cardioid microphone so that only more sensitive from the front. Figure one opening, right in front of the di- their music is picked up, not sounds 4-a shows a parabolic reflector micro - aphragm.

www.americanradiohistory.com Both the reflector and line micro- formation curve as cutoff frequency is phones are directive, but neither com- HORN DIAMETER approached, with a smooth transition pares with the narrow beam of the lA 1/ 1 3x from a high -directivity pattern to one horn shown in Fig. 6. Figure 6-a of lower directivity. Such smooth shows the geometry of the basic horn transitions are more desirable than the shell for the horn microphone pro- abrupt low -frequency cutoff of both horns. totype, without the screw-on exten- FIG. 7-AS HORN MOUTH SIZE increases exponential and hyperbolic sion piece, while Fig 6-b shows the relative to wavelength, directivity in- In the horn of Fig. 6-a, the transi- directivity patterns for different fre- creases, since audio wavelength is com- tion from square horn to receptor is quencies. parable to mouth size. Shown are smoothed into a cone using modeling directional patterns of decreasing beam- clay. At the higher audio frequencies, All microphones, of whatever type, width, for four horn diameters relative to work equally well when the same X. the conical walls reflect the short basic shape is used in a loudspeaker wavelengths (a few inches or less) due to reciprocity. The narrow beam Hz to a few hundred Hz, the wave- down to the microphone diaphragm, of a horn stems from the ability to lengths are over a foot. At helping to optimize high -end audio match the impedance between a small f =1.115483 kHz, then X =1 ft, so the directivity for a narrower beamwidth. microphone diaphragm and free air, 1 -foot diameter horn presented here making the small microphone di- should be quite directive at that fre- aphragm (or receptor) seem as large quency. Figuré 7 shows additional di- l.2 h YP ER BO as the mouth of the horn. rectivity patterns, but not for explicit 1.0 frequencies. Note that those patterns -- are for various mouth sizes relative to 8 I wavelength. As the ratio of mouth 6 size to wavelength increases, so does E KPO N Eti In AL 180` directivity. Another way to achieve 4 higher directivity is to increase horn CON CAL 2 length for a given mouth size. As MICROPHONE ELEMENT shown in Fig. 8, to achieve this, the o (RECEPTOR) horn angle a must be reduced. 200 Hz 1 kHz 10 kHz 20 kHz AUDIO FREQUENCY a FIG. 9-RELATIVE ACOUSTIC resistance for several horn microphones of size and bandwidth similar to Fig. 6. Each works just as well as a loudsjeaker by reciprocity, with the exponential, hyperbolic, and conical the most common. Construction 4 kHz 7 kHz 1 kHz The horn presented here can be made using low-cost materials and a little time. Because sound pressure FIG. 6-HORN MICROPHONES ARE VERY directive; they match acoustic impedance waves exert low force, light -weight from diaphragm to open air. In (a) are the materials can be used. Figure 10 prototype dimensions; the narrow beam - shows the prototype, made from cor- width makes the receptor act as large as OPEN MOUTH the mouth, due to phasing and pressure OF HORN HAND F effects, so the incident volume is greater from the front, than sides or rear. In (b) are directivity plots for 1, 4, and 7 kHz. FIG. 8-ANOTHER WAY TO ACHIEVE directivity in a horn microphone is to increase length versus mouth size, requir- Horn microphone ing that horn angle cx be reduced. The high directivity of all horn microphones stems from phasing and Horns of different shapes are com- pressure effects, making the volume monly used as loudspeakers, with the at the receptor greater from the front, exponential, hyperbolic, and conical than from the sides or rear. The versions the most common, in that mouth, length, shape, and frequency order. Horns are uniquely able to range to be received, all determine the transform and match acoustic imped- directivity. One reason for the high ances. The horn loudspeaker is an directivity is that audio wavelengths acoustic transformer, changing large MICROPHONE are made comparable to the mouth pressures and small volume currents FIG. 10-THE PROTOTYPE HORN WAS size. The relation is X = C/f, where X in the throat to small pressures and made from corrugated cardboard; a re- larger mouth and is wavelength (cm), C is speed of large volume currents in its mouth; movable extension with a carrying handle was added. At high au- sound (340 m/s), and f is frequency in horn microphones do the reverse. dio frequencies, the walls reflect short Hz. As shown in Fig. 9, the conical wavelengths of a few inches or less to the Since 1 ft = 30.48 cm, then from 20 horn has a gradual impedance -trans- diaphragm, to optimize directivity. 43

www.americanradiohistory.com %a" DUCT TAPE BASE OF HORN

DIRECTION OF CORE TUBES OF 12" CORRUGATED CARDBOARD

.0-6" -+. 6" Ii 6" --

24" CUT 4 PIECES FIG. 11-HERE'S THE CUTOUT FOR ONE side of the basic horn; note the direction of the corrugated ribs. The edges have slight curvature so the sides have added strength, and don't resonate easily. The edges were taped, and paper glue was used on the inner and outer corners. The small end was cut to a 1 -inch diameter, and the microphone slides in and is held by the four sides. A metal washer slipped into the throat face acts as a stop, yet lets the sound reach the diaphragm. BASE OF MICROPHONE ELECTRICAL TAPE FIG. 13-A CLOSE-UP VIEW OF THE EXTERIOR of the neck. The carboard is tapered, producing an opening of proper size for the microphone, and the microphone is inserted. Note the silvery ring at the base of the horn, just behind the base of the horn. The MODELING CLAY WASHER bottom of the microphone protrudes from the base of the horn, and was sealed mechanically and acoustically with duct tape, while the base of the horn was stiffened with electrical tape.

square horn to the round washer open- STIFFENING RIBS ing, so the sound wasn't prevented from reaching the diaphragm. The FACE OF washer needs an opening at least 75% MICROPHONE of the microphone diameter. Figure 13 CORRUGATED CARDBOARD shows a close-up view of the exterior OF HORN MICROPHONE of the neck of the horn. You can see 24" how the cardboard is tapered to pro- FIG. 12-WHEN MOUNTING THE micro- duce an opening of the proper size for phone in the horn, the washer aperture should be at least 75% of the diaphragm the microphone, and how the micro- diameter. The modeling clay smoothed phone is inserted. the transition from the square horn to the Note the silvery ring at the base of 24,. washer opening, so that the sound wasn't the horn in Fig. 13, just in front of restricted from reaching the diaphragm. where the microphone apparently CUT 4 PIECES ends. The base of the microphone (DIRECTION OF rugated cardboard, cut to the correct protrudes from the base of the horn, CORE TUBES) size and glued together, with a carry- and is sealed mechanically and acous- ing handle added. The horn was con- tically with duct tape. The extension FIG. 14-HORN EXTENSION CUTOUT; the ribs stiffen the cardboard. The extension structed, assembled, and tested; then, in Figs. 14 and 15 slips over the front slips over the horn, extending its length a removable extension was added to of the basic horn, to extend the length and expanding its mouth, and two 1/4-20 gauge the benefits of a larger mouth. and expand the mouth, and two 1/4-20 screws with washers hold both together. The basic horn was built with four screws with washers hold both sec- The mouth is now 2 x 2 ft, one wavelength sides from the pattern in Fig. 11. The tions together. across at f=557.742 Hz, matching wave- edges have for lengths down to lower audio frequencies, slight curvature addi- By adding the extension, the mouth improving directivity, raising the pressure tional strength, so they won't resonate was increased in size from 1 x 1 ft to level by 3 dB, and providing better low - easily. The edges were taped enough 2 x 2 ft, quadrupling the area. Also, frequency pick-up, since impedance to hold them in place, and simple the new size is one wavelength across matching is improved. white paper glue was applied to both at f=557.742 Hz, matching wave- Testing the outside and inside corners. The lengths down to lower audio frequen- The preliminary tests were con- small end was cut to a 1 -inch diameter, cies and increasing directivity beyond ducted at a large parking lot at a local letting the microphone slide in and be that of the basic horn alone. The beach. In actual use, aim the horn in held by the four cardboard sides. A larger diameter and greater total area the direction of the desired sound, and metal washer slipped into the throat improves pick-up, raising the the- plug the microphone into a tape re- against the microphone face acts as a oretical pressure level by 3 dB. In corder, allowing playback later on. In position stop, while letting the sound practice, the horn picks up more at evaluating the prototype, all tests reach the diaphragm. lower frequencies because the imped- were recorded to allow detailed sound As Fig. 12 shows, modeling clay ance matching at those frequencies is pressure evaluation of an individual smoothed the transition from the improved. (Continued on page 52) 44

www.americanradiohistory.com LAST MONTH WE INTRODUCED YOU TO THE LAWN RANGER, THE world's first personal robotic lawn mower. For those of you who missed last month's issue, the Lawn Ranger is a computerized robot that can cut grass by itself. All you have to do is cut a This month boundary around the perimeter of your yard and around any we obstacles using the manual controller, switch the mower to discuss the automatic, and watch in amazement as it completes the job. motor -controller board.

Control system Let's quickly review the block diagram of the electronic control system shown in Fig. 1. The grass -sensor assembly is used to detect the position of cut and uncut grass that lies beneath the Lawn Ranger. id That information is amplified on the motor- øuild controller board and then forwarded to the Central Processing Unit (CPU). The CPU will calculate the steering direction and send it to the motor-control - ler board. The motor -controller and the Lawn power -switching circuitry will steer the robot in the varying defined by the CPU by varying e l the speed of the rear drive flgi"iI wheels. If the right wheel is made to spin faster than the left .. wheel, the robot will steer to j*. the leftjust as a tank works. Motor -controller board Figure 2 shows a block diagram of the motor -controller board, which is used to control the speed of each drive wheel and to amplify the grass -sensor signals. The motor -speed control circuitry contained on the board is designed to increase or decrease power to the drive motors based upon the drive motor's actual speed. The circuitry has three major sections: the D/A converter, velocity -feedback loops, and Pulse -Width Modulators (PWM). The D/A converter converts the Z80 microprocessor's digital steering command into an analog voltage. The D/A converter, hand-held manual controller, and speed -set adjustment provide steering reference signals to the velocity -feedback loops. There are two feedback loops: one for the right wheel, and one for the left. The loops are designed to "lock on" to the reference -signal input and provide a constant motor speed. The D/A and the manual -controller outputs are designed to slow down the left or right wheel for steering purposes. When the robot is steering straight, the D/A and manual -control outputs will be zero and Remond Rafaeis both drive wheels will spin at the same speed. If the actual wheell speed (from the velocity -feedback signal) is equal to the desired wheel speed, the error voltage will be zero. When the wheel speed is too slow, the velocity -feedback signa will c` r- cause the error voltage (reference input minus the feedback ì to increase and additional power will be delivered to the drive motors. If the wheel speed is too

Lanat Ranger is a regi.stererl IradenmrA of Terhnìral.Solatinns 45

www.americanradiohistory.com SENSOR ASSEMBLY'

MOTHER BOARD

SENSOR AMPLIFIERS

I/O VELOCITY FEEDBACK CPU MOTOR CONTROLLER CIRCUITRY VELOCITY FEEDBACK

CPU BOARD MOTOR CONTROLLER BOARD

LEFT MOT CUTTER MOTOR CIRCUIT 12V POWER CUTTER DRIVE 1ni 1- 24V MOTORS DC/DC Li CONVERTER RIGHT + in 12V i MOTOR POWER BOARD

BATTERIES

FIIG. 1 -BLOCK DIAGRAM of the electronic control system.

fast, the velocity -1 cdback signal will achieve high -efficiency power ampli- efficiency. The "on" and "off" times cause the error voltage to decrease and fication. The technique allows the are precisely controlled and the effect less power will be delivered to the + 24 -volt supply to be switched (ap- on the motors is the same as if a lower drive motors. plied and then removed) from the voltage were continuously applied to The PWM circuitry is used to drive motors for the sake of increased them.

PARTS LIST R20-2.7 megohms Capacitors MOTOR -CONTROLLER R22, R36, R48-220,000 ohms 01, 05, 07, C10, C11, 016, C18 -C21, All resistors are 1/4 -watt, 5%, un- R24-82,000 ohms C26, C42, C47-051-0.1 µF, 50 less otherwise indicated. R29-680,000 ohms volts R1, R93 -two 16 -ohm, 1 -watt re- R31 -R35, R37, R104 -R106, 02, 04, 08, 015, 043-C45-0.01 µF, sistors in parallel R117 -R200 -not used 25 volts, iìsc R2, R16, R28, R41-22,000 ohms R40, R42-68,000 ohms C3, C9, C27-041-1 IF, 35 volts, R3. R17, R21, R25, R43, R55, R56, R49-820,000 ohms electrolyt c R59, R60, R73, R83, R86, 890- R51, R57, R109. 8111, R113, R114, C6, C17, C46-100 µF, 35 volts, elec- 100,000 ohms R116-8200 ohms trolytic R4, R5, R18, R19-2200 ohms R58, R61-39,000 ohms C12-014, C22-0.002 µF, 25 volts R6, R30, R38, R39, R44, R45, R47, R63, R64, R81, R82, R94-1000 C23 -C25-10 µF, 16 volts, R50, R108, R110, R112, 8115-1 ohms, 1% electrolytic megohm R66, R68, R74, R87-270 ohms R7-806,000 ohms, 1% R67, R70, R77, R80-3300 ohms Semiconductors R8-402,000 ohms, 1% R71, R76, R85, R88-2700 ohms 101, 1012-1014-74LS14N hex R9, R26, R27, R52-200,000 ohms, (with 0.1 µF capacitor in parallel, inverter 1% see text) IC2-74LS74N D -type latch R10-150,000 ohms R91, R92, R107-jumper 1C3. IC11-not used R11, R23, R46, R53, R54, R62, R65, R95, R98, R102-3900 ohms, 8 -pin IC4, IC7-LM324 op amp R69, R72, R75, R78, R79, R84, SIP resistor network 105, IC6-LM2907N-8 frequency -to - R89-10,000 ohms R96, R97, R99 -R101, R103-2200 voltage converter R12-499,000 ohms, 1% ohms, 8 -pin SIP resistor network 108-LF13292 analog switch R13-180,000 ohms R201, R202-2000 ohms, IC9, IC10-UC3637N pulse -width R14-604,000 ohms, 1% potentiometer modulator R15-4500 ohms, 1% R203 10.000 ohms, potentiometer IC15, IC18-LM339 comparator

www.americanradiohistory.com VELOCITY FEEDBACK

MO -OR TONTROLI ER BOARD LEFT LEFT TACH s MOTOR CIRCUITRY

L. FORWARD LEFT ERFOR MOQJR MA/ L. REVERSE SUM IUCI&7 ST I FF.I JG NPD SUM IF -1. MCCR PrVPA POWER HAND FILE UC 363T BOARD MAr U'L CON-F©L R E T yor L. FOR 2 INPUT SF EED SET L. REV 2 RIGH FORWARD/ INV RECE TSE RIGHT LOGIC R. FOR TACH FO3 CIRCUITRI POWER 30ARD

R. Rf

GRtiS SEN=CF() IrJ I11 RIGHT I\P_TS MOTOR

S -:ERLAG VELOCITY FEEDBACK NEC

FIG. 2-TIE Y/10 -OR -CONTROLLER B:C.RC is used to control the speed of each trine wheel and to amp the grass -sensor signals.

D/A converter Note: The fc flowing items can be Figure 3 shows a detailed sche- motor -controller 1016, IC-7-LLN2081A transistor purchaE DC from Technical Solu matic diagram of the array tions, Inc., P O. Box 284 board. The D/A circuit uses op-amp IC19, IC 2J-0PB822S dual op -o Damas_us, MD 20872 (301 IC4-b, which is basically an inverting modu e 253-4913: PC boards for the summing amplifier that adds the volt- D1 -C3, DE -211, D13, D15, D17, CPU, m Dtnr-ccn-roiler, power ages from data bits DAO-DA5. The D20-D22-1 N4148 diode board, and mcllErboard, $39 lower the amplifier input resistance, D4, D5, D12, D14, D16, D18, D19- each; pr-Dç rammed E 2ROM, $39 the higher the gain for that particular program not us?: (contains compu-e data bit line. The resistance (and gain) and firnware icEnse); grass 02, 03. 5 06, Q8, 09, 011-016- used to couple the six data lines to the 2N331:4 transistor sensors 28.99 Eadi; hand-held input of the summing amplifier will 01.04.' ', C10 -2N3906 transisbr manual centroler kk, $39; full Other co-nocnents CPU -beard kit, $12g (includes vary by a factor of two. For instance, R20) J1 -20 -pi- D: connector EPROM, PC board, and all the resistance at DAO (R12 and J2-not used parts);'uI kit f:r motherboard, will be twice as large as the resistance J3-10-pir D: connector $69 (contains PC board and all at DAI (R6 and R14), which will be J4-16-pir D: connector parts); bit for poker board, $149 twice as large as DA2 (R7), etc. That Miscellaneous: PC board, IC sock- (contains bcarc aid all parts allows the magnitudes of each binary ets (twc .3pir , nine 14 -pin, three 1E - except DC/DC :crverters); fur number to be properly weighted with -controller board, pin and 'W) 18 -pin), jumper wie. kit for motor respect to each other. A small bias -tc. $169 (contains :C beard and an solde voltage is applied through Rl3 and MOTHERBOARD parts); _a Nn Ra, g Dr demo VHS R203 into the summing junction to PC D rc; P21, P23 -44 -pin edga tape, $13 refundable for orders D/A output to swing both cor neC10'; P22 50 -pin edge cor - of $100 Dr more;. F lease add $8 force the C nec' or for S H (L.S. o -des . Maryland positive and negative. Potentiometer resideris add sales tax. R203 will adjust the level of the D/A Text continued on page 71 o 47

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www.americanradiohistory.com 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

LAST MONTH WE BEGAN OUR DISCUSSION print. We have therefore put Listing 6 be dedicated to the LCD module. A on alpha -numeric LCD's, and showed in this second half of the article, processor that does not have dedi- you how to use them in your own shown below. cated port pins requires a small designs. We showed you how they can amount of additional decode logic in eliminate components and intercon- Hardware interface order to establish the LCD module as nections when used instead of 7 -seg- There are a variety of ways to inter- an I/O device. ment displays. Let's finish up now, so face an LCD module to a host pro- LCD modules with an on -board that you can actually use one in your cessor or microcontroller. A micro - HD44780 LCD controller chip have next project. controller such as a Motorola two hardware interface modes: a 4-bit MC68705 (see Radio -Electronics, mode and an 8 -bit mode. In the 4 -bit Last month September 1989, for information on mode, each data byte is transferred to Before we begin, though, there is the MC68705) is easy to interface the LCD module with two write oper- something from the first half of this with because it has port pins that can ations. The 4 -bit mode utilizes only article (Radio -Electronics, June 1990), that should be pointed out. At the end of the story, we had said that LISTING 6 once the display has been properly JSR INIT INITIALIZE DISPLAY initialized, the ASCII codes must be LDA #$8O SET UP FOR DD RAM WRITES written to the display with a series JSR CONTROL of LDA #S02 RETURN DIPLAY TO HOME POSITION Data Write operations. We told you JSR CONTROL that the "SET DD RAM ADDRESS" LDA 'P' JSR DISLET \ command must precede the data oper- LDA 'L' ations to ensure that the data goes to JSR DISLET DD RAM and not CG RAM, and that LDA 'A' JSR DISLET LOAD AND DISPLAY EACH LETTER data writes to CG RAM must be pre- LDA 'N' OF THE WORD 'PLANE ' ceded by a "SET CG RAM AD- JSR DISLET LDA 'E' DRESS" command. As an example, JSR DISLET we said that the routine in Listing 6 LDA would display the message JSR DISLET LDA , #S02 ASCII CODE FOR AIRPLANE TAIL SECTION "PLANE," assuming that the user- JSR DISLET defined Character Generator RAM LDA #$01 ASCII CODE FOR AIRPLANE BODY SECTION was set up as defined in Listing 5. JSR DISLET LDA #$00 ASCII CODE FOR AIRPLANE NOSE SECTION Well, Listing 5 did appear in that arti- JSR DISLET cle, but Listing 6 never made it to

www.americanradiohistory.com PC3 LCD tAß 10 DISPLAY PC2 MODULE PC1 + 5V RS PC0 2 PB719 VOS 18 R1 PB6 10K- Vo R/W 68705P3 PB5 20K 16 PB4 s 15 PB3 DATA 14 4 (DBO- DB71 INT PB2 RS 13 5 PB1 R/W 12 6 VPP PBO E E 27 14 PA7 DB7 tE 26 13 EXTAL PA6 DB6 tE - 450 ns MINIMUM 25 12 tAS - 140 ns MINIMUM t5 - 20 ns MINIMUM PA5 DB5 24 11 XTAL PA4 DB4 23 10 PA3 DB3 22 9 TIMER PA2 DB2 tAs -I 21 8 PA1 DB1 8 20 RESET PAO DBO RS /

FIG. 5-TO INTERFACE A MICRO - CONTROLLER to a HD44780-based LCD and R/W module, simply connect the control data lines of the module directly to the port pins of the microcontroller.

DATA (DBO- DB7) some additional logic as shown in Fig. 6. That logic establishes the LCD module as being an I/O device in addition to providing the required setup tcYc time on the Rs line (The Rs line must be stable for 140 nanoseconds before tcy, tE, tAs, tH SAME AS 8 BIT MODE - 1Ns MINIMUM - the ENABLE line is strobed). In that b configuration, the LCD module is ac- cessed using "IN" and "OUT" in- FIG. 4-THE TIMING REQUIREMENTS for the 8 -bit mode (a) and the 4 -bit mode (b). structions for reads and writes the upper four data -bus lines saving of four data -bus lines. The 8 - respectively. Data operations are dis- (DB4-DB7). In the 8 -bit mode, data bit mode is slightly easier to interface tinguished from control operations by bytes are transferred with a single with (with respect to software), so you the address of the I/O operation with write operation which saves time by should therefore use the 8 -bit mode address 00 (hex) being a control oper- using all eight data -bus lines unless the project that you've de- ation and address 01 (hex) being a (DBO-DB7). The only advantage to signed uses a microcontroller that has data operation. The I/O address of the using the 4 -bit interface mode is a a limited number of available port LCD module can be changed very pins. Figure 4 shows the timing re- easily by changing the chip -select de- quirements for both the 8- and 4 -bit code logic. ORDERING INFORMATION mode. Sample project The following items are available Microcontroller interface The prototype display module has from Simple Design Implementations Interfacing a microcontroller to a been incorporated into an automated (SDI), P.O. Box 9303, Forestville, CT HD44780-based LCD module is as check list for airplane pilots. The 06010 (203) 582-8526: Experi- simple as connecting the control and check-list project uses an menter's kit (contains 16 x 1 OPTREX data lines of the module directly to the MC68HC701 (similar to the LCD module, programmed port pins of the microcontroller as MC68705) for the host micro - -control poten- MC68705P3, contrast shown in Fig. 5. Note that R1 is the controller, a series of pushbutton IC socket, soft- tiometer, PC board, contrast -control potentiometer for the switches for scrolling up and down ware listings, schematic, and instruc- the lists, and a small beeper tions), $29.95 + $3 S/H; Same display. check that sounds every time a button is experimenter's kit with 40 x 1 display, $39.95 + $3 S/H; Programmed Microprocessor interface pressed. The LCD is 16 characters `c MC68705P3 and instructions, Interfacing the HD44780-based wide by 2 lines for a total of 32 r- $15.95 + $2.50 S/H. LCD module to a processor (such as characters. Since the current draw of c-o (D the Zilog Z80 8 -bit CPU) requires the LCD was less than the load ca - o

www.americanradiohistory.com ADDRESS BUS MICROPHONE + 5V 5 Al 5 continued from page 44

Al 4 DD

A13 2 speaking, in a normal R1 L VD voice, 100 ft 10K- 20K Al 2 from the mouth. The resultant record- All ing was quite intelligible even above 40 A10 seagulls squawking overhead, the 39 surf, and car noises 500 ft away. A9 I/O ADDR (00 HEX) - INSTR. 38 I/O ADDR (01 HEX) - DATA The higher audio frequencies so A8 37 necessary for speech intelligibility A7 CHIP SELECT LOGIC tend to be very directive. Noticeable A6 36 35 roll -off occurred 5° away from the A5 (Al -A7) main axis of the in 34 LCD SELECT horn; fact, speech A4 LCD wasn't understandable when the horn 3 A3 MODULE microphone wasn't pointed directly at 32 Z80 CPU A2 someone. Beyond 10-15° off-axis, a Al 31 voice vanished completely into back- 30 AO AO RS ground noise. However, seagulls and 13 14 D7 DB7 birds 75-100 ft away sounded like 10 13 D6 DB6 they were 2 ft in front of a regular 9 12 D5 DB5 microphone. 11 BASIC D4 DB4 HORN MICROPHONE HANDLE 10 D3 DB3 12 9 D2 DB2 15 D1 DB1 14 7 DO DBO 24 27 WAIT M1 6 19 INT MREQ 17 20 NMI IORQ 26 21 RD 5 RESET R 25 22 +5V BUSRQ WR 2 4 28 CLK D RFSH PR 5 6 18 o CL O HALT 74LS74 BUSAK 2 3C Oo-_6

FIG. 6-INTERFACING THE HD44780-BASED LCD module to a microprocessor requires some additional logic.

STIFFENERS HORN TEMPERATURE EXTENSION SENSOR LCD DISPLAY MODULE FIG. 15-HERE'S THE COMPLETED TEMPERATURE HORN MICROPHONE. SENSOR At the top is the HOST THE TEMPERATURE IN receptor microphone, then comes the STEVE'S ROOM IS 75° (687051 /- basic horn, and lastly, the horn extension TEMPERATURE is shown with its support ribs. SENSOR Surprisingly, the extension didn't

FIG. 7-TRY USING AN LCD MODULE to build a multi -zone thermometer that displays really improve directivity, and appar- temperatures throughout your house with your own custom messages. ently wasn't worth the effort, given the time and effort needed, as well as pability of the port pins of the micro - As a suggestion for your own proj- its size. Frequency response tests with controller, the LCD is powered di- ect using an LCD module, why don't polar pattern measurements would be rectly from a port pin of the you try to build a multi -zone ther- needed for verification of this, and to microcontroller. That allows the con- mometer that displays temperatures optimize the extension performance. venient feature of letting the micro - throughout your house with simple, However, recording bird calls and ani- controller power down the display non -cryptic messages. For example, mal sounds is a perfect application for when it's not needed in order to con- you could display "THE TEMPERA- this horn, since both the horn and serve battery power. It should be TURE IN STEVE'S ROOM IS 72°." extension are small enough for field noted that the entire design uses fewer A block diagram of such a project is use, and give excellent performance than thirty interconnecting wires. shown in Fig. 7. R -E over the full audio range. R -E

www.americanradiohistory.com CANADA

U NITED S TATES

International radio in the U.S... The shortwave banes preach religion, pol/ti AFRICA and rock -n -roll to the world.

ROCK, GERRY L. DEXTER RELIGI NAND RHETORIC

PRIVATE U.S. SHORTWAVE BROADCASTERS In 1948, a new law governing U.S. went unnoticed. The first major are a pretty select group. Out of a total shortwave broadcasting made the change came in 1982, when WRNO of over 10,000 private broadcasters VOA a permanent government entity, Worldwide, of New Orleans, LA, be- under FCC control, only about 15 of but encouraged private broadcasting gan broadcasting, after which the them use shortwave, or the High Fre- by forbidding a government monopo- FCC found itself granting licenses at quency (HF) range from 2 MHz -30 ly on radio, and particularly short- an increasing rate fast. Here's a cap- MHz. However, while this overall wave. The law let the VOA lease sule look at the current private U.S. number may seem small, the 1980's private shortwave stations from NBC shortwave broadcasters: witnessed a 500% increase in U.S. and Crosley Broadcasting; this prac- KGEI, of Redwood City, San shortwave stations, which is an out- tice continued until about 1960, when Francisco, CA, was owned by GE for standing growth rate. the VOA shortwave station in Green- several years, then sold to Far East In the 1930's, when radio had the ville, NC was finished. As private Broadcasting Company, a worldwide potential and excitement that cable leases expired, however, nearly all religious group. KGEI, "The Voice of and satellite TV offer today, many private firms opted to get out of the Friendship," transmits mainly in U.S. broadcasters like GE, West- shortwave broadcasting business. Spanish to Latin America. It runs 50 inghouse, and the major radio net- The postwar U.S. shortwave au- and 250 kilowatts on 6.010, 6.075, works tried shortwave HF, in addition dience dropped drastically, mainly 6.095, 6.150, 7.365, 9.615 and to AM. The potential U.S. audience due to the popularity of television, 15.280 Megahertz. was sizable because many old floor- and the elimination of shortwave WYFR, owned by Family Sta- standing living-room radios included bands on postwar home receivers. By tions, Inc., of Oakland, CA, a large shortwave bands. As shortwave radio 1960, the only two remaining private religious group, can trace its history developed, so did the potential au- broadcasters were WRUL and KGEI, back to WRUL of Massachusetts in dience for it. although WINB was added in 1963. the 1930's. The "Voice of Freedom" Then, however, came World War That year, the FCC froze further ap- for the VOA in World War II, it moved II. The government soon recognized plications for shortwave station li- to NY City and worked with the anti - the obvious need for an international censes, until new rules could be Castro movement in the early 1960's. voice to combat Axis propaganda. written to account for changes in in- It was owned by CBS, the Mormon There was no time to wait for facilities ternational shortwave broadcasting Church, and was WNYW (Radio NY to be built, so the government nation- regulations. Worldwide) for years. Family Sta- c alized private shortwave stations for That took 10 years, but afterward, tions bought it in 1972, changed to the first Voice Of America (VOA) four years elapsed before KTWR be- WYFR (Your Family Radio), closed broadcasts. gan broadcasting from Guam, which WRUL, moved to Okeechobee, FL, 0co

www.americanradiohistory.com aired 24 -hour "Super Rock" music to Japan, was announced in Japanese, and was programmed in Los Angeles, CA. However, despite shortwave sets being fairly common in Japan, it lost money and was sold to Herald Broad- casting (WCSN). KYOI uses 100 kilowatts in English on main frequencies 9.670, 11.900, 15.405 and 17.780 MHz. KFBS, the second shortwave station owned by the Far East Broadcast- ing Company (FEBC), whose main shortwave station is KGEI, reaches Asia with religious programming. KFBS has three 100 -kilowatt transmitters, one formerly used by VOA, Greetings from KNLS, the New Life Station, P.J. Bo, 473, and airs in Burmese, Indonesian, Anchor Point, Alaska 99556, United StatEs cd America Mandarin, Malay and Vietnamese. Main frequencies are 7.365, 9.465, FIG. 1-KNLS OPERATES FROM THIS BUILDING at Ancho Point, AK. 9.575, 9.830, 9.840, 11.980, 12.025, 15.305, and 15.375 MHz. FEBC also and added several 100 -kilowatt trans- has other large shortwave stations in mitters. Besides religious programs, the Philippines and Seychelle Islands. WYFR works with Taiwan as VOFC KSDA, on Guam, is owned by (Voice of Free China), heard in the Adventist World Radio, another re- U.S. and Asia. Broadcasts go around ligious broadcaster. It uses two 100 - the clock in many languages, on over kilowatt transmitters, aimed at Asia in 50 frequencies. several languages about 20 hours a WINB, owned by World Intl. day on main English frequencies of Broadcasters, of Red Lion, PA, is a 11.965, 15.125 and 17.685 MHz. religious shortwave station. It uses 50 There are smaller shortwave stations kilowatts, covering North Africa, Lat- in Italy, Guatemala, and Costa Rica. in America, Western Europe, and the KNLS (New Life Station), owned Mediterranean, in several languages, by World Christian Broadcasting, of and broadcasts run 11 hours a day on Texas, started in 1983 from Anchor 15.145, 15.150 and 15.185 MHz, and Point, AK, after two staff members other frequencies. were killed in a plane crash, and an KTWR, on Guam, is run by Trans arsonist burned down the 100 -kilowatt World Radio, a worldwide religious transmitter. Main frequencies are organization started in the 1950's. It 6.095, 7.355, 9.535, 9.750, 9.870, has four 100 -kilowatt transmitters 11.700, 11,820, 11.960, 11.930 and covering China, Indonesia, India, Ja- FIG. 2-PART OF THE TRANSMITTING FA- 11.980 MHz. KNLS airs to Asia in pan, SE Asia, and parts of the USSR. CILITY at WHRI it Nobelsville, h. Chinese, Japanese, English and Rus- Trans World also has shortwave sta- sian, but hasn't reached Europe due to tions in Monaco, Swaziland, and Bo- severe HF absorption and refraction at naire in the Dutch Antilles. KTWR the North Pole. This occurs during airs in English and 10 other lan- solar events like aurora, sunspots, guages; English frequencies include proton events, or geomagnetic sub - 9.590 and 11.805 MHz. storms, which expands the WRNO (Rock of New Orleans) is ionosphere. The bottom moves closer owned by Joseph Costello III, of New to the Earth, the top elevates, and the Orleans, LA, who also owns affiliated charged particle density increases, AM/FM stations there. Its early pro- degrading HF propagation. A picture grams had FM simulcasts, but it's of the station from a listener-con- separate now and has some 40 re- FIG. 2-A CONTROL FOOM O>=RATOR firmation card is shown in Fig. 1. ligious programs, including rock, INSPECTING broadcast equipment at WMLK is run by the Assemblies pop, New Orleans Saints football, and KUSW, in Satt Lake City, UT. of Yaweh, Bethel, PA, a religious other sports. WRNO showed up in group that took two years to convert audience surveys halfway across the 6.185, 9.495, 11.965, 13.760 and an old 50 -kilowatt AM transmitter to U.S., too far away to have been the 15.420 MHz. shortwave. They transmit a few hours AM station. It uses two 100 -kilowatt KYOI, owned by Marconi, Inc., a day on 9.455 MHz from a converted transmitters, programs are nearly all on Saipan in the U.S. Northern Mar- gas station. Programming focuses on English, and the main frequencies are ianas Islands, wasn't as successful. It the premise that salvation awaits only

www.americanradiohistory.com those who worship God by the Old bought KYOI, which now carries U.S. listeners from listening to the Testament name, Yaweh. The station WCSN via satellite. Next year, broadcasts impossible. call sign is a contraction of "Malek," WCSN will add WSHB in South Car- The FCC sets a minimum power or "Messenger." olina, with a pair of 500 -kilowatt level of 50 kilowatts as its require- WHRI (World Harvest Radio), of transmitters aimed at Latin America. ments for international shortwave, South Bend, IN, is owned by LeSea WWCR (Worldwide Christian Ra- whereas on AM, 50 kilowatts is the Broadcasting, part of Lester Sumrall dio), of Nashville, TN, is a new re- maximum; however, that's still small ministries. They also have AM/FM ligious broadcaster that may be potatoes. WCSN is just one of many and TV operations, and were badly starting up any time, perhaps by the worldwide shortwave stations that damaged by fire last year. However, time you read this. WWCR will be now uses 500 kilowatts, and even 2.5 WHRI missed minimal air time, as part of a multi -station group of AM/ megawatt shortwave stations are com- broadcasts were switched to a standby FM outlets in the south, and will have mon. The shortwave broadcaster transmitter in Nobelsville, IN. There a 100 -kilowatt transmitter, and sell needs complex directional HF anten- are two 100 -kilowatt transmitters program time to churches, other re- nas aimed at the desired area, along aimed at Latin America, the Middle ligious groups, and maybe even polit- with requirements like minimum an- East, and North Africa, on 6.100, ical groups or other stations that can't tenna gain, HF signal launch angle, 6.155, 7.355, 7.400, 9.455, 9.745, reach North America. bandwidth, and site selection. Once 9.765, 9.770, 11.770, 11.790, 11.980, In contrast with AM/FM stations, running, the right frequency has to be 15.105 and 17.830 MHz. LeSea has shortwave stations are much more adjusted to reach a specific area, at a several TV stations and a satellite up- complex and expensive. The FCC specific season and time of day. It's link transmitter. Figure 2 shows an won't grant international shortwave not just a case of needing only one operator working on part of the trans- transmitter, antenna pattern, and fre- mitting facility at the station. quency, all the time. KVOH (Voice of Hope), in Chris- An ordinary AM/FM station is ex- tian Southern Lebanon, is owned by pensive, but not when compared with High Adventure Ministries in Califor- a shortwave station. George Jacobs is nia, and got started literally under the a former official of VOA and Radio gun. Broadcasting has continued for Free Europe (RFE), who now heads several years, despite a rocket attack his own highly regarded broadcast - that destroyed the studios. They re- engineering firm, which acts as tech- cently started KVOH from Rancho nical consultant to several U.S. short- Simi, CA, in English and Spanish for wave broadcasters. According to him, the Americas using 50 kilowatts on a 50 -kilowatt site with suitable anten- 9.495 or 17.775 MHz. Their next nas goes for about $400,000, while a project is to transmit from the Phi- 500 -kilowatt version can easily run Ilipines to China. $2.5 million. And that's excluding KUSW, of Salt Lake City, UT, is the land, studio, and buildings, which one of only two commercial U.S. can easily double the overall cost. He shortwave broadcasters. It's part of estimates the power cost for a 500 - Carlson Communications, which kilowatt site 18 hours a day for a year owns an AM/FM outlet there, and at over $53,000. several others in the western U.S. So far, programming formats have KUSW runs a pop format, and runs FIG. 4-TRANSMITTING TOWERS AT been mostly of two types, and one has several commercials, though really KUSW, IN Salt Lake City, UT. to wonder how much more audience big accounts like Coca-Cola haven't potential exists for religious program- yet been obtained. KUSW airs 18 broadcast station licenses unless ap- ming. Pop and rock formats, already hours a day on 5.980, 6.010, 6.185, plicants can prove there's a real need, filling AM/FM bands, are also heard 9.852, 11.980, 15.225, 15.580 and that they have the technical, program- on many foreign stations, both AM/ 17.715 MHz. Figure 3 shows a control ming, and financial capability, and FM and shortwave. The curtain hasn't room operator inspecting broadcast will serve the "public interest, con- fallen on this play yet, though. There equipment at the station, and Fig. 4 venience and necessity." are still a few more actors yet to ar- shows the transmitting towers there. A key item in the FCC rules says rive. WCSN (Christian Science Net- that "any program solely intended for The oldest and largest religious work), of Scotts Corner, ME, is and directed to the U.S. doesn't meet shortwave broadcaster of all, HCJB of owned by Herald Broadcasting, part the requirements for this service." Quito, Ecuador, is planning a facility of Christian Science Monitor. It airs a Thus, these shortwave stations aren't on Hawaii to better reach Asia and the two-hour English news/features seg- supposed to broadcast to the U.S., but Pacific. Other companies are report- ment several times a day around the many obviously do. The key appears edly considering shortwave stations world. On weekends, the program is to lie in the use of the word "solely," California, Kentucky, and Florida. the "Herald of Christian Science" in which apparently allows a U.S. au- Beyond that, whether that strange English, French and German. WCSN dience to listen in, so long as the world above AM, still alien to most in runs 500 kilowatts on 7.365, 9.465, programming is officially aimed North America, will prove a good 9.852, 15.280, 17.640 and 21.515 elsewhere. Also, the physics of short- place for broadcasters in the 1990's, is MHz. As noted earlier, WCSN wave propagation make preventing yet to be seen. R -E 55

www.americanradiohistory.com alarm occurs, but then automatically turns off and disables the siren after SECURITY-CIRCUIT some preset period if manual reset hasn't occurred, typically 5-15 minutes maximum. The circuit of Fig. 3 shows how to interconnect the three COOKBOOK units when a single supply battery is used, and the circuit of Fig. 4 shows We continue our survey of home -security system principles how to accomplish the same for dual supplies. by looking at sirens, and various types The circuit of Fig. 5 shows a practical auto -turn-off circuit with a basic of "fault -indicator" alarms. timing period of about 8 minutes. The period is proportional to CI, and can be doubled, for example, by using: RAY MARSTON CI = 0.2 µF. Here, ICI is a 17 -Hz 555 IN OUR MAY ISSUE WE REVIEWED THE astable multivibrator that feeds clock basic operating theory and installa- pulses to IC2, a 14 -stage binary coun- tion principles of home-security sys- ter that changes state on the 8192nd tems, and examined several practical clock pulse. OUTPUT security -alarm circuits that give a SELF-LATCHING (N.O. RELAY When power is first applied, the SENSOR high degree of protection against fire, CONTACTS) output NETWORK o of IC2 is set low via C2. As the burglary, or intruders. All of them had output goes low, RY1 is driven on via a relay output that can activate an ex- B1 QI, closing the contact. That turns on SIREN ternal siren via a pair of relay con- ICI, which starts operating and feed- tacts. ing pulses to the input of IC2. When In practice, the siren can also be a the 8192nd clock pulse arrives after bell or buzzer, either electro -mechan- FIG. 1-HOW TO CONNECT A SIREN to a about 8 minutes, the output of IC2 ical or electronic. The first half of this relay -output burglar alarm, with a single flips high and turns relay RY1 off via article describes ways of connecting supply. Q1, shutting off ICI and the siren, sensor systems and sirens, and de- completing operation. scribes some practical circuits, while The 8 -minute period of the circuit B2 the second half describes various shown in Fig. 5 SELF -LATCHING - OUTPUT is fairly long, but is types of "fault -indicator" alarms. SENSOR (N.O. RELAY accomplished without resorting to NETWORK CONTACTS) large electrolytic capacitors or re- Siren configurations sistors. The period is determined by A siren can use the same supply as B1 SIREN time constant R2 x Cl, and has excel- the actual sensor system it's used L lent repeatability and thermal sta- with, or each may need separate bility. Note that LEDI is a visual power. All home -security systems FIG. 2.-HOW TO CONNECT A SIREN to a intrusion indicator that lights as long should have battery backup for power burglar alarm, with double supplies. as voltage is present, and it continues outages. If the sensor system and si- to glow even after the siren shuts off. It ren use similar voltages, and the sen- the siren until it's reset manually, or alerts the owner to the presence of an sor system self-latches via relay, both the supply is cut off. The main pur- intruder after the fact, even if no overt can run off of the same supply, as pose of a siren is to scare off intrud- disturbance occurred to cause one to shown in Fig. 1. ers, while alerting the owner and/or take notice during the incident. If, however, the sensor system and neighbors. If that isn't achieved in a siren need different supplies or the few minutes after activation, there's Electronic siren circuits sensor system doesn't self-latch, they clearly no point in letting the siren to A siren can be a bell, siren, buzzer, absolutely must have separate sup- continue to operate. Thus, simple or other sound siren, whether electro- plies, as shown in Fig. 2. A siren self-latching action tends to be rather mechanical or electronic. In some induces considerable noise on its sup- inefficient. cases, two sirens, connected either in ply, which can cause a non -latching A far more efficient type of siren parallel or via dual -contact relay may alarm to malfunction with one supply. can be obtained by interposing an au- be a good idea. For example, an elec- tomatic turn-off timer between the tronic siren could be used inside a Auto -turn-off alarm system sensor system and siren, as shown in house, while a bell sounds outside. Once a self-latching sensor system Figs. 3 and 4. Both versions incorpo- Electronic sirens can take a number of is activated, it automatically sounds rate a relay that closes as soon as an different forms, and can generate very

www.americanradiohistory.com You can greatly increase the maximum supply voltage and available 1 output power by modifying the design OUTPUT 2 SELF-LATCHING AUTO -TURN-OFF ° (N.O. RELAY to limit the supply to IC1 to 12 volts SENSOR UNIT CONTAC1S) DC with a 12 -volt zener diode while NETWORK OUTPUT1 increasing the speaker supply to 30 T (N.O. RELAY volts DC. The version shown in Fig. 6 81 CONTACTS) generates a "dee-dah" warble tone, similar to that of a British police car Z. siren. It generates a maximum of 18 FIG. 3.-CONNECT A SIREN to a burglar alarm via auto -turn-off, with a single supply. watts into an 8 -ohm speaker using 24 volts DC. 1+ The frequency -shift "symmetry" of the circuit shown in Fig. 7 depends OUTPUT? B2 perfor- SELF -LATCHING AUTO -TURN-OFF (N.O. RELAY somewhat on the individual SENSOR UNIT CONTACT31 mance characteristics of ICI. The cir- NETWORK o OUTPUTI cuit of Fig. 7 shows an alternate (N.O. RELAY warble -tone generator that doesn't CONTACTS) SIREN suffer from this defect. The modulation frequency is varied via R2, and the tone frequency via R5. It uses a FIG. 4.-CONNECT A SIREN to a burglar alarm via auto -turn-off, with double supplies. pair of 555's, rather than a single CMOS IC.

Here, ICI is a 1 -kHz astable multi - +12VDC vibrator, and IC2 is a somewhat high- D2 01 astable multivibrator, e 2N3906 1N4001 er-frequency R3 around a few kHz. Note that this de- 6.8K R5 16 OUTPUT 47052 sign is based on the use of a pair of R1 C2^ N.O. 555 timers, rather than on a single 15K o- IC1 is used as a 1 - IC2 11 '1 o CMOS IC. Here, ICI 4020B kHz astable multivibrator, while IC2 555 R2 N.O. 470K R4 LEDI is used as a higher-frequency astable -o ; 1MEG INTRUDER multivibrator, around a couple of 10 Its DICATOR kHz. Astable multivibrator ICI fre- D3 quency -shifts IC2 by feeding a Cl íy. C3 1t14001 100µF D1 square -wave to the pin -5 modulation 1 1N4001 (MYLAR), terminal. You can generate a variation on that theme, creating a "wailing" tone, al- FIG. 5.-AN AUTO -TURN-OFF UNIT with 8 -minute delay. ternately rising and falling like that of an American police siren, by using an emitter follower to buffer the 1 -Hz +12VDC signal of ICI. The +4- "sawtooth" OUTLINE OF +1 C2 D1 sawtooth signal is then fed to pin 5 of Gc 0 SPKR THE VN67AF 100µF 1N4001 8S2 IC2, the modulation terminal of the higher -frequency astable multi -

14 vibrator. 12 8 10 h -- The circuit shown in Fig. 8 gener- ICI -a 3 IC1-b IC1-c 11 IC1-4 G ates a "zeep-zeep" tone similar to the /4 40118 1/4 4011B 13 1/4 4011 1/140116 9 "Red Alert" signal on "Star Trek." . R3 S R1 17 C3_L 01 The period is varied via R2, and the C1 R2 68K 017 6.8MEG .1 220K 4N67AF' tone via R6; this is an ideal hobby T project. Here, DI and C2 are used to FIG. 6.-WARBLE-TONE 6 -WATT SIREN with VMOS output. ensure that the astable multivibrator isn't adversely affected by voltage distinctive and easily recognizable Hz astable multivibrator, that alter- transients resulting from the inductive sounds. The circuits of Figs. 6-8 nately gates the l -kHz astable multi - characteristics of the SPKR. show three useful versions. vibrator made from ICI -c and ICI -d The circuit shown in Fig. 6 gener- on and off via pin 8. The resulting Touch- and proximity -alarms `C r- ates a warble tone siren. Here, ICI is a warble -tone is amplified by a A commonly -used home -security NAND gate, and ICI -a VN67AFVMOS output stage to gen- technique is that of arranging baited ó quad CMOS (D and ICI -b are used to make a simple 1 - erate 6 watts in an 8 -ohm speaker. "traps," like door handles, clocks, o 57

www.americanradiohistory.com metal trays, etc., in such a way that they sound an alarm whenever they're +12-15VDC touched. If the bait is a small metal 1 C2 R4 01 object, one way of achieving this 470µF 10K 1N4001 SPKR effect is to use a "hum -detecting" 812 1N4001 touch sensor system, of the type R5 220K shown in the circuit shown in Fig. 9. The shown in 9 circuit Fig. detects R3 the AC hum that's picked up by an 10K 1N4001 electrical contact when it's touched

by a human finger, when the individu- C3 01 al in proximity to an AC power line. 01 2N3055 Here, one of the gates of a CD4001B is used as a simple pulse -inverting amplifier, and has its input terminal FIG. 7.-ALTERNATE WARBLE -TONE siren like that of a British police car. connected to the external metal object via Rl. This gate is powered by 5 volts + 12-15VDC - -+-1 C2 DC, derived from 12 volts DC via R2 R1 470µF SPKR and R3, and biased via R5 so that its 10K> 10KR5 e 1N4001 R4 ( af2 output is normally low. 7 = 4.7K a - R2 R6 D3 When a pick-up signal with a peak ICI 02 33K 100K 6 IC2 1N4001 555 R3 2N3904 amplitude greater than a couple of 555 6 volts D1 2 appears at the input, the gate 3 11Ñ R7 184801 2 output is a 5 -volt, 60 -Hz square wave, 2.7K that activates RY1 via Ql-Q2 and D1 - C1 -R4. Sensitivity -control R5 is ad- Cl 2N3906 - C3 justed so that RY1 turns on and sounds 47µF 01 an alarm when the object is touched, and shuts off when the object is released. Note that the low side of the FIG. 8.-"RED-ALERT" SIREN simulating "Star Trek" alarm signal. 12 -volt DC supply must be properly grounded. The circuit draws a quies- off RY 1. When the antenna created by OUT cent current of 1 milliamp. If the ob- the external metal object is touched or N.O. is 10 Q1 ject placed more than cm from additionally loaded, cuts off, cut- A o o R3 the input, the connections to it must ting off Q3. In that case, Q4 is D2 12VDC 6.8K use shielded leads, to prevent stray positively biased via R8, turning RY1 1N4001Ä (>120f2) signal pickup. on and sounding an alarm. Note that 10 01 The circuit of Fig. shows another transistors Q1 and Q2 are fed using 6 5.6K - version; in that case, the object is part volts DC via D3, ensuring good os- 2N3704 of the antenna of an RF oscillator. The cillator stability. circuit uses capacitive -loading, where The circuit of Fig. 11 shows an alter- o-. +12VDC R4 47K the gain of the RF oscillator is ad- nate output stage for the circuit shown Cl 02 justed so that oscillation is barely sus- in Fig. 10, for direct activation of a .47, 2N3704 tained, and the antenna is part of the self-interrupting 12 -volt bell or buzzer D1 tank circuit; as before, the low end of with a current rating or 2 amps or less 1N4148Ä 14 the supply must be properly via SCR1. Either version is very sim- 40018 2 grounded. Consequently, any in- ple to set up. Connect a suitable an- 3 1/4 R1 100K crease in the antenna -to -ground ca- tenna, and adjust R9 until RY1 turns 5,6,7,8, pacitance, like that caused by on. Back off slightly on R9 so RY1 9,12,13 R5 touching or approaching the antenna, turns off, then check that the alarm is 4.7MEG causes enough damping of the tank sounded when is the antenna touched 44,1 circuit to reduce the oscillator gain or approached, and off when contact (INPUT o SENSITIVITY below critical level, cutting off the or proximity stops. If necessary, ad- FROM METAL oscillator, and turning on the siren. just R9 again for maximum sen- OBJECT) In this case, Q1 is a Colpitts os- sitivity. cillator running at about 300 kHz, FIG. 9.-"HUM-DETECTING" TOUCH sensor system. with the gain adjusted by R9, and the Sound- and vibration -alarms antenna coupled to the tank circuit via Sound -activated alarms can be types use the same principle, as C5. The output of the oscillator is made to activate when an intruder en- shown in the block diagram shown in buffered via Q2 and rectified via DI - ters a protected area and creates noise. Fig. 12. In this case, a microphone or D2, to produce a positive bias that's Vibration -activated alarms can be other kind of similar transducer picks fed to the base of Q3. When Q1 is made to activate when a drawer or up the basic noise or vibration, which operating normally, Q3 is driven to cabinet is opened, inducing a small is then amplified and rectified, and saturation and Q4 is cut off, turning vibration in a protected object. Both the resulting DC is used to sound an

www.americanradiohistory.com + 12VDC N.O. ANT OUT 4 OU -1 R5 N.O. R1 R3 . ' O I o o D4 A O T C5 56K 2.7K: 1.2K D3 = -Á, 6V +12VDC T .Ot11 1N4001 ----- 02 12VDC -T--o----- 2N3704 2N3704 >12052) D3 äo 12VDC i! ZCl 01 1N4001 C6 le (>12052);i 200pF 2N3704 D2 ii -- .01 1N4148 81.J 01 iC2 ( 1,1 94A i, R7 R2 263704 200pF R6 JI R4 27KS 2.2K 47K 3.3K 02 2N3704 C4 D1 C3i R921 1N4148 .01 5K --J S M - :. C7 +1 R2 GAIN i .1 (SEE TEXT) 56K: 6 D2 R1 1N4148 100K FIG. 10.-RELAY-OUTPUT "PROXIMITY" sensor system.

Cl D1 The circuit of Fig. 14 shows a prac- 10µF 1N4148 +12VDC tical speech -amplifier circuit to be TO R6 INPUT . D R8 D3 used in conjunction with the circuit 4.7K 1N4001 shown in Fig. 13 to make a sensitive FIG. 13.-SIMPLE RELAY-OUTPUT sound - or vibration -sensor system. R10 sound -activated alarm. The RCA 1K CA3035 IC is an ultra -high -gain SCR1 wide -band amplifier array, with a OUT (TO INPUT C106Y1 OF FIG 16) R6 voltage gain of 120 dB between pins 1 2211 and 7. In that circuit, R1 and CI per- FROM D2 form biasing, R5 controls gain, and the other components determine bandwidth. FIG. 11.-ALTERNATE DIRECT OUTPUT stage for the circuit shown in Fig. 13. Flood -alarm systems alarm. One of the many dangers facing the The circuit of Fig. 13 shows a sim- house owner is flooding, like occurs ple sensor system, that needs about 1 - when a water cistern overflows, a volt RMS to turn on RY1. The circuit water pipe breaks, or rain leaks into a action is such that RY1 turns on cellar. Fortunately, those dangers can MICROPHONE rapidly when a suitable input signal be greatly reduced with the aid of a appears, but turns off slowly when the simple water-activated sensor system, FIG. 14.-SPEECH-FREQUENCY AMPLI - 15 signal is removed. The turn-off time is of which the circuits shown in Figs. fier used in conjunction with the circuit of determined by time constant RI x C2, and 16 are practical versions. Each of Fig. 16 to make a sound -activated sensor which is most easily changed by vary- the two circuits uses the same basic system. ing C2. operating principle, which involves UT That version can be made self- using a pair of metal probes to re- -+ 12VDC v---° ÑO. latching by using additional contacts sistively detect the presence or ab- ; o 0 for RY1, placed across Q2 as shown. sence of liquid. D1 It can be used as a sound- or vibra- In the absence of liquid, the probes 1N4001 i 12VDC Q2 r-(>120S2) tion -activated sensor system by feed- see near-infinite resistance, but when 2N3702 ing AC from a pickup transducer, via liquid appears across both probes si- - a suitable amplifier. In vibration multaneously, the probe resistance 03 alarms, the amplifier should have a falls to a low value, sounding an 2N3704 low-pass response, while sound - alarm. For rain or tap water, the resis- alarms must operate with a band-pass tance may be less than a few kilohms, 01 a R3 R4 response. but steam or oil may exhibit higher 2N3702 1K 1K

R2 R1 4.7K 1 10MEG SELECTIVE SIGNAL RELAY REN AMPLIFIER DETECTOR C1 PROBES J .047 FIG. 15.-SENSITIVE FLOOD -ALARM sys- FIG. 12.-BLOCK DIAGRAM OF TYPICAL SOUND- or vibration -sensor system. tem with relay output.

www.americanradiohistory.com Try the +5-15VDC

R1 C2 C3 Rails Cl e 10MEG R2 .0011( .047 14 01 8` R5 2N3702 NVr- IC1-a 3 IC1-c 10 10K 1/4 4001 bulletin board 2 1/4 4001B e9/j system R3 e R4 R6 1MEG 820K

12 (RE-BBS) 5 10052 PROBES 516-293-2283 TOTAL SPKR

The more you use it the more 7 useful it becomes.

We support 300 and 1200 baud FIG. 16.-SENSITIVE PULSED -TONE flood -alarm system. operation.

Parameters: 8N1 (8 data bits, no D1 D2 D3 1N4001 1N4001 K1N4001 D4 parity, 1 stop bit) or 7E1 (7 data TI = R14 2 1N4001 bits, even parity, 1 stop bit). 12K 6V + BUZZER 01 Add yourself to our user files to 120VAC 12VAC 2N3704 R3 B1 increase your access. 1K SCR1 9VDC +.-. Cl C100Y1 470pF Communicate with other R -E 18WVDC R4 readers. 1K

Leave your comments on R -E with FIG. 17.-BELL/BUZZER POWER -FAILURE ALARM system. the SYSOP.

RE-BBS resistance of as much as several used. When 120 VAC is applied, RY1 516-293-2283 megohms. turns on, the N.C. contacts open, and The operation of the circuit shown the siren stays off; when power cut in Fig. 15 is very simple. In the ab- off, RY1 turns off and the contacts sence of liquid, Ql is held cutoff via close, sounding an alarm. Here, RY1 R1 -R2, so Q2 and RYI are off also. In can be any 12 -volt type with a coil the presence of liquid, Q1 turns on, resistance of at least 120 ohms, with biasing Darlington pair QI -Q2 on via one or more N.C. contacts; trans- R3 and turning on RY1, sounding an former TI needs a current rating of at alarm. It turns on when the resistance least 100 milliamps. between the probes is under about The secondary winding of trans- 500K, and has a sensitivity of about former TI is rectified and smoothed 10 megohms, by using a Darlington by D1 -C1 to 12 -volts DC at the junc- pair in place of Q1. Finally, the circuit tions of D1 -D2 and D2 -D3. The siren shown in Fig. 16 generates a pulsed - is a self-interrupting bell or buzzer tone alarm when activated, with a with current rating of 2 amps or less, sensitivity of about 20 megohms, and is the anode load of SCR1, consumes about 1 µA of quiescent powered by B I. current, and generates an 800 -Hz tone Normally, when 12 -volts DC ap- that's pulsed on and off at a rate of 6 pears at the junctions of D1 -D2 and Hz. D2 -D3, Q1 saturates via R1, and the junction of R2 -R3 junction goes to Power -failure alarm systems ground. In that case, no drive is ap- THE Electrical -power failure alarms can plied to the gate of SCRI, so the siren ULTIMATE be made to activate when power is is off, D3 is reverse -biased, so no cur- ELECTRONICS removed from an electric major appli- rent is drawn from B1. When the CATALOG ance like a freezer, either due to a power cuts off during a failure, the D1 Order your 260 page catalog and price list with over downed power line, or when fuse junction of -D2 goes to ground, 14,000 money saving electronic parts and equipment! blows. The circuit shown in Fig. 17 cutting off Ql. That feeds current to Send $3.00 in a check or money order, or call shows a version that trips an alarm via 1-800-643-3668 today and use your Mastercard or Visa. the SCR gate from BI via D3 -R2 -R3, Consolidated Electronics, Incorporated RY1. The output winding of trans- turning on SCR1 and sounding an 706 Watervliet Ave., Dayton, Ohio 46420-2699 former T1 is 12 -volts RMS, which is alarm. Next month, we'll conclude half-wave rectified by D1, smoothed this look at security devices, by exam- Name by Cl, and fed directly to RY1. ining some practical smoke and heat Address The contacts of RY1 City State Zip can sound an alarms, and several different car alarm if Normally-Closed (N.C.) are alarms. R -E CIRCLE 70 ON FREE INFORMATION CARD 60

www.americanradiohistory.com Put Professional Knowledge and a GAUGES 3 -DIGIT DISPLAY BOARD COLLEGE DEGREE 1/4 un- All resistors are -watt, 5%, in your Technical Career through continued from page 40 less otherwise indicated. R1, R2-220 ohms R3-220 ohms (voltmeter only) VACUUM GAUGE Semiconductors All resistors are 1/4 -watt, 5%, un- ICI--CA3161 E, Display driver less otherwise indicated. DISP1-DISP3-0.43" 7 -segment R1, R2-10,000 ohms C.A. LED display (Panasonic R3, R8-100,000 ohms LN514RA) R4-22,000 ohms Q1 -C3 -2N3906 PNP transistor R5-1000 ohms LEDI -5- x 15 -mm LED, (Pan- R6-680,000 ohms asonic LN0202RP) R7, R10-200,000 ohms PC mounted trimmer potentiometer 2 -DIGIT DISPLAY BOARD R9-82,000 ohms All resistors are 1/4 -watt, 5%, un- Add prestige and earning power to R11-50,000 ohms PC mounted less otherwise indicated. your technical career by earning R1, R2-220 ohms trimmer potentiometer your Associate or Bachelor degree R12-2200 ohms Semiconductors Capacitors ICI-CA3161 E, display driver through directed home study. C1-47 µF, 25 volts, electrolytic DISF1, DISP2-0.43" 7 -segment College of Engineering C.A. LED display (Panasonic Grantham C2, C3-10 µF, 35 volts, electrolytic accredited degrees in C4-0.33 µF, 50 volts, stacked film LN514RA) awards Semiconductors 01, Q2 -2N3906 PNP transistor electronics and computers. ICI-Sensym SX3ODN vacuum sen- LED' -5 x 15 -mm LED, (Pan- sor (Dakota Digital #69G18 in- asonic LN0202RP) An important part of being pre- cludes mounting bracket) pared to move up is holding the IC2-LM324, quad op -amp is essentially a bridge circuit with its IC3-LM340T-5, 5 -volt regulator outputs at pins 2 and 4. Because it is a right college degree, and the abso- IC4-CA3132E, A/D converter bridge, its outputs change propor- lutely necessary part is knowing D1, D2-1N4002 diode tionally to one another when vacuum your field. Grantham can help you Miscellaneous: 43B17 main PC or pressure is applied. When both both ways-to learn more and to board, 2 -digit display board, in -line ports have the same pressure, the out- earn your degree in the process. fuse holder, 1 -amp fuse, four 6-32 puts at pins 2 and 4 are identical. As x 0.625" standoffs, eight s/,s-inch vacuum is applied to port 2, the out- Grantham offers two degree pro- #6 screws, bronze or red plex- pill 4 is re- iglass, mounting hardware, hookup put at pin 2 rises while grams-one with major emphasis wire. duced. There is now a difference in electronics, the other with major between the two outputs of the bridge, emphasis in computers. Associate represents how and R8 form a resistive divider that and that difference and bachelor degrees are awarded sets the upper reference voltage, with much vacuum is present. in and both pro- a range of 0.284 to 0.889 volts. The The first two sections of IC2 are each program, low -temperature calibration is ad- used as buffers to isolate the bridge grams are available completely justed via R7, while the high -temper- circuit of IC1. IC2-a is used as a dif- by correspondence. ature calibration is adjusted via RI1. ferential amplifier, and R1 -R3 and R8 A three -digit display is used, and the determine the gain. Resistors R6 and No commuting to class. Study at annunciator can be anything you R7 are used to offset the differential your own pace, while continuing "OIL," etc.. amplifier so that its normal "zero" on your present job. Learn from The vacuum gauge, shown in Fig. output is 0.21 volts above ground. The easy -to -understand lessons, with 7, uses a solid-state vacuum/pressure gain of the differential amplifier is set help from your Grantham instruc- sensor (ICI, Sensym SX3ODN) to to give an output approximately 60% tors when you need it. monitor the intake -manifold vacuum higher than that needed by the A/D during engine operation. Between 0 converter. The voltage level is then Write for our free catalog (see address and 30 inches (in.) of mercury (Hg.) reduced by R9 and R10, which is also below), or phone us at toll -free can be displayed with 1 in. Hg. resolu- used to set the full scale of the gauge. 1-800-955-2527 (for catalog requests convert- tion. The sensor consists of a piezo The input voltage to the A/D only) and ask for our "degree catalog." resistive element housed in a dual er is averaged by C3 for stable read- ported plastic enclosure. The piezo ings. Resistors R4 and R5 set the Accredited by element changes its resistance as it is 0.21 -volt "ground" reference which the Accrediting Commission of the flexed or bent. Because a specific is buffered at the output of IC2, pin 7. National Home Study Council amount of flexing is caused by a spe- The vacuum value is displayed on a cific force or pressure, the value of two digit readout. A "VAC" annun- that pressure can be determined by ciator on the display board indicates GRANTHAM measuring the sensor's resistance. the reading of the gauge. College of Engineering re Vacuum has the same effect as it pulls That's all we have room for this the element instead of pushing it. month. Next month we'll build and 10570 Humbolt Street The pressure/vacuum sensor (ICI) install the gauges. R -E Los Alamitos, CA 907202 61

www.americanradiohistory.com Electronic Melody Chips Unusual Book Resources HARDWARE Ten Speed Blender Control Power Control Fundamentals Hacker Interchange Standard

HACKER DON LANCASTER Power -control fundamentals

AS WE'VE SEEN IN PAST COLUMNS, WITH - in a decade we just may reasonably A very interesting report titled as user's hands? expect electronic hardware having Electricity by Serendipity appeared Or dialplates, drilling templates, computation abilities that are as in the March 2, 1990 issue of detailed test and debug info, soft- complex as those of the human Science. It describes a new type of ware listings, or most any other tech brain. Driven primarily by ultra - fuel cell which permits the writing or tech illustrations? cheap and ultra -dense dynamic premixing of the hydrogen and oxy- Putting any of those in the maga- RAM technology. gen gases, something previously zine does take up valuable space, Now, admittedly, my timing on thought to be utterly impossible. and the third -generation pho- this might be off by as much as These cells also involve hydrogen tocopies or litho negatives you twenty minutes in either direction. being absorbed or adsorbed into sometimes end up with are often of But, things seem to be going even palladium, in cells remarkably sim- low accuracy and quality. And it sure faster now than they were even a ilar to the cold -fusion setups. gets hard to make a correction three few issues ago. The obvious unanswered ques- months later on 360,000 already Several Japanese outfits have now tion is "how much of cold fusion's printed pages, some of which are actually firmly scheduled their fu- excess heat is really this previously buried in a lesser-known suburb of ture production of new 256 Meg x unknown type of fuel cell?" And Moose Jaw, Montana. 17 SIMM chips. And it appears an- vice versa. On the other hand, the BBS other level of threshold effect just Our usual reminder here that downloading will work only if the might have been crossed with the most of the resources mentioned sender and sendee do have fully concept of OOPS or object oriented have been gathered together into compatible hardware and software. programming which is spreading the Names and Numbers or the What to do? like wildfire. Unusual Book Resources sidebars. I would like to suggest an obvious So how can you tune yourself into You can contact all the listees di- solution. It is called an EPS file, and and profit from this near-term inev- rectly for more info. is short for Encapsulated PostScript. itability of human brain computer Let's start with a lively topic... An EPS file can easily handle any functionality? printed -circuit board layout, sche- As usual, those free industry trade Printed circuit standard matic, isometric or perspective journals are the answer. In this case, The editors at Popular Electronics, drawing, dialplate, or text or graph- the E.E. Times is a very good choice. Radio -Electronics, Probe, Midnight ics of any sort to any arbitrarily high They are very big on dynamic RAM Engineering, Computer Shopper, resolution. developments, on neuron comput- Nuts and Volts, Byte, Audio Ama- The EPS files are extremely device ing, and on "fuzzy logic" in general. teur, and Circuit Cellar Ink have all independent. Since an EPS file is an Cold fusion. This is being written been separately grappling with a ordinary ASCII text file, it could easi- on cold fusion's first birthday. Ac- common problem: How can clean ly be used with any word processor cording to today's Wall Street Jour- and accurate printed -circuit layouts or any editor with any brand of per- nal (April 3, 1990, page B4), "a small get easily and cheaply put in the end sonal computer of anyage and CPU. but growing number of scientists At the output end, an EPS file can believe they are seeing an entirely be used directly on a laser printer, new NEED HELP? phenomenon," and "There is by a typesetter, or by a photoplotter. now a growing consensus that you Phone or write your Hardware With simple and crude emulators can't explain Hacker questions to: the excess energy by such as Freedom of the Press, Go - errors." It appears, in fact, that sev- Don Lancaster Script, and UltraScript, you can also eral distinct and valid cold -fusion Synergetics print your results on ordinary dot- mechanisms might be involved. Six- Box 809 -RE matrix or ink -jet printers, albeit to a teen laboratories have recently re- Thatcher, AZ, 85552 lower resolution. The latest of fax ported fresh and positive new (602) 428-4073 machines are set up to directly han- results. dle EPS files, some to device-inde-

www.americanradiohistory.com pendent resolutions that can ex- rupt the program or system that the peres with a drop of only a volt or ceed 2650 DPI. There is no high -end EPS file is being imported into. Sev- two. A modest heatsink is usually limit to print quality. eral other obscure commands (such needed to handle the current. Fig- Better yet, practically all of those as settransfer) must be carefully ure a square inch or so for each 50 CAD/CAM and illustration packages saved and restored if they are al- watts of load. either now use PostScript internally tered. EPS files are also limited to a As a long-term solid-state on -off or at the very least are capable of single page each, but you can use as switch, a triac can handle most any generating EPS output files. many of them as you like. AC load within its current rating, The EPS files can also be ex- To get started on all of this, get and still work equally well with any tremely compact. For instance, a yourself copies of the Encapsulated style lamp, heater, or motor. fancy circuit schematic should need PostScript Files Specification, v 2.0, You can pick up an 8 -amp triac at no more than a 10K textfile max- and the Document Structuring Con- Radio Shack for $1.40, and you'll imum. So, EPS stores cheap and ventions Specification, v2.1. Both of find several low-cost triac selections downloads fast. them are available free upon re- among our many Radio -Electronics But what if you are using an ex- quest through Cynthia Johnson at advertisers. Three major suppliers pensive or proprietary CAD/CAM or Adobe Systems, or else through one of triacs include Motorola, SGS, and layout package? Surely you could of the PostScript BBS systems. You Texas Instruments. While all three not provide a free copy of these to should not create or use any EPS have lots of triac data books and every reader in the country, could files without having these two on application notes available, none you? Especially if you are on a Mac hand. could even think of holding a candle and they are on a PC. The fundamentals on PostScript to the original and classic GE SCR There is a simple little trick you are covered by Adobe's blue Manual, which, sadly, is long out of can pull that is called pseudo -com- PostScript Tutorial and red print. piling. With pseudo -compiling, you PostScript Reference Manual, while While triacs are fun to experiment might convert any source of ready-to -use printed -circuit layout, with and easy to use, do note that PostScript code into a Just the facts, schematic, isometric, and perspec- you are dealing directly with the AC Ma'am form that uses nothing ex- tive routines are found in my power line. You have an extreme, cept the simplest of put -and -place PostScript Show and Tell. and possibly lethal, shock hazard. PostScript commands. Anyone can Let me know your thoughts on a run a pseudo -compiled EPS file, and standardized hacker interchange absolutely nothing will remain of approach based on standard EPS file NEW FROM the original code or the way it was formats. generated. DON LANCASTER Better yet, that pseudo -compiled AC power control HANDS-ON BOOKS PostScript often will run ridiculously Most hackers have observed at Hardware Hacker Reprints II 24.50 faster than the original. And one time or another, that your typ- Ask The Guru Reprints I or II 24.50 pseudo -compiling is easily and ical semiconductor will instantly va- CMOS Cookbook 18.50 it across the TTL Cookbook 16.50 quickly done by using Adobe Sys- porize if you connect Active Filter Cookbook 15.50 tem's brand new and cheap AC power line. Obvious problems Micro Cookbook vol I or II 16.50 Distillery program, by one of my here are that the power line is high Enhancing your Apple I or II 17.50 AppleWriter Cookbook 19.50 gonzo justification routines, or your voltage, high current, and either po- Apple Assembly Cookbook 21.50 own custom code. larity. Incredible Secret Money Machine 10.50 In semiconductor that LaserWriter Reference (Apple) 19.50 What about screen images? any One popular PostScript Cookbook (Adobe) 16.50 broad based user interchange stan- can easily be used as a high -power PostScript Ref. Man. (Adobe) 22.50 dard, you certainly would not want AC line switch is called a triac. A PostScript Prog. Design (Adobe) 22.50 Type I Font Format (Adobe) 15.50 to use any screen images if they hurt typical on -off circuit is shown in Fig. Real World Postscript (Roth) 22.50 the device independence in any 1. UNLOCKED SOFTWARE way. A triac has two power terminals Fortunately, systems using display called Ti and T2, and a control termi- LaserWriter Secrets (Ile/Mac/PC) 29.50 PostScript Show & Tell 39.50 PostScript or the display PostScript nal called the gate. A triac remains Intro to PostScript VHS Video 39.50 emulation are now becoming read- off until a low-level pulse (usually 5 PostScript Beginner Stuff 39.50 is PostScript Perspective Draw 39.50 ily available, as is software that re- volts at 50 mA) of either polarity PostScript Technical Illustrations 39.50 turns printer bitmaps for screen applied to the gate. The triac then PostScript BBS stuff 19.50 display. So are programs and ap- turns on its main terminals and re- Absolute Reset Ile & llc 19.50 AppleWriter/Laserwriter Utilities 49.50 plications that internally capture mains on so long as the main cur- Enhance I or II Companion Disk 19.50 and display EPS. rent continues flowing in the same AppleWriter CB or Assy CB Disk 24.50

How does an EPS file differ from direction. FREE VOICE HELPLINE VISA/MC an ordinary PostScript textfile list- Thus, a triac turns on very shortly ing? Actually by very little. There are after it receives a gate pulse. It stays SYNERGETICS a few required remarks at the start of on until the next zero crossing of the Box 809 -RE Thatcher, AZ 85552 your file plus a few optional ones. main AC current through it. (602) 428-4073 And a very few PostScript com- When off, the triac can block the mands (such as initgraphics) are not full applied line voltage. When on, allowed if they would somehow cor- the triac can conduct several am- CIRCLE 83 ON FREE INFORMATION CARD

www.americanradiohistory.com Even with the safety isolation, you fancier and carefully crafted circuits. still have a severe shock hazard on Here is how your simple dimmer the right side of Fig. 2. control works: The diac shown con- Observe that the interface works sists of two four -layer diodes back to backward from what you'd expect. back. It behaves sort of like a neon A low input powers your load, and lamp. It is an open circuit until its vice versa. That makes far better use terminal voltage gets up to fifty volts of the micro's current -sinking ports. or so. Then it will suddenly turn on, Under certain conditions, a triac dumping the capacitor charge into can be used to control the bright- the triac gate. The diac turns back off ness or speed of your power load. when your capacitor is discharged. WARNING: Extreme shock hazard! One way to do that is by using phase Varying the brightness control de- control, such as is shown in Fig. 3. If cides how fast the capacitor you precisely delay the gate pulse to charges, and thus when in the cycle FIG. 1-A TRIAC CAN BE USED as a line - some point in the AC half cycle, only the triac fires. operated AC power switch that can di- partial AC half cycles will get The later in the cycle, the less the rectly control lamps, heaters, or motors. A through to the load. Since full percentage of the time that power is brief and small current pulse into the gate power is applied for only part of the applied to the load, turns the triac on; it remains on until the and the dimmer main current reverses. time, you end up with an average the lamp. Since this all happens 120 lower power sent to the load. times per second, the repeated off- Always keep one hand behind your But note that phase control will on actions are well beyond your crit- back. Never leave power applied not work with any old power load. ical persistence of vision limit, and after a test or experiment. And al- Phase control is fine for heaters, sol- no flicker will be noticeable. The ways use an isolation transformer dering irons and other resistive long thermal inertia of the lamp fila- should you want to view any scope loads, and is really great for incan- ment also helps eliminate flicker. waveforms. descent lamp dimming. While Diac trigger diodes are usually Figure 2 shows you one simple phase control can be used to con- sold by the same sources who sup- computer -to-AC -power interface. trol the speed of a universal AC -DC ply triacs. These days, though, it is You take a special optocoupler motor which uses brushes, a slightly far better to digitally generate all the known as a phototriac isolator and fancier feedback circuit that senses power line phase delays by either use it as a safety interface. When the motor back EMF will often work using a micro -processor or a custom your computer port goes low, an considerably better. power control chip. One example LED in the isolator turns on, which Note that a simple phase control might be... fires up an internal baby phototriac, absolutely, positively must never be that in turn whomps the main triac. used with a fluorescent lamp or an Touch -controlled blender That safety isolates your computer AC induction motor. While it is pos- Certainly one of the most obscure from the power line, yet still allows a sible to use triacs to dim a fluores- and low -profile IC chip houses is LSI small logic signal to directly control cent or to control the speed of an Systems. Yet, those folks do have an a kilowatt or more of AC line power. induction motor, they need much outstanding selection of the low- cost hacker integrated circuits. They are particularly strong in AC power controls, counters, timers, delay circuits, electronic locks and melody chips. 100 watt light bulb Figure 4 shows you their LS3714 22052 chip as it's used for a ten -speed touch -controlled blender. It can 110 VAC also be used for a ten -level dimmer. Cost in singles is a mere $2.75, drop- ping to seventy cents in production 2N6154 quantities. MOC 3010 TRIAC There are eleven touch plates phototriac used; touching any one sets that optocoupler selected power level to the load. Their circuit consists of a touch -sen- 3305 WARNING: sitive one -of -eleven latch which se- +5V Extreme shock hazard on lects and remembers your desired right half of this circuit! power level. That level is converted PORT into a phase angle which deter- mines when to fire the main power- control triac. A reference input on FIG. 2-A MICROCOMPUTER-TO-TRIAC interface uses a phototriac optoisolator to let safety -isolated logic signals directly control high -power loads. Depending upon the input pin 12 synchronizes an internal waveforms and the load, this same circuit can be used for either an on -off or a propor- phase locked loop to the power line tional phase control. A low input powers the lamp. zero crossings. Double resistors are

www.americanradiohistory.com keep our circuit simple here. You can also customize all of your firing angles to improve linearity for your selected load. Consult the data 100 watt sheet for full details on these extras. light bulb 22K Play a simple melody 250K As an entirely different LS! Sys- 110 VAC tems circuit, Fig. 5 shows you a 2N6154 LS3404 melody chip. There are 31 TRlAC melodies in stock, and you can also (in large quan- 0.1 µF customize your own tities) tunes up to 255 notes long. The envelope of each note gets adjusted to an exponential decay to WARNING: Extreme shock hazard! produce a high -quality, chime -like tone. The circuit shuts off after each tune. The operating current is five FIG. 3-A PHASE -CONTROLLED DIMMER delays the triac turn -on to a selected point in mils. Pitch is set by the RC values at each successive AC half cycle. Use this circuit ONLY for incandescent lamps, heaters, pin 5. Decay time is set at pin 3. Pin 4 soldering irons, or "universal" motors that have brushes. sets the tempo. Be sure to get a complete set of used on the touch plates as a safety thus lighting one -of -ten selected LSI data sheets. These folks do have feature. LED lamps to show your current over three dozen low-cost chips that

The active touch -plate inputs can power or speed level. I have left the cry out for new hacker uses. What also double as LED output drivers, RFI noise filter off the output to can you come up with here?

UNUSUAL BOOK RESOURCES

Antique Radio Books Frontier Space Books SAE 498 Cross Street 240 Foshay Tower 400 Commonwealth Dr Carlisle, MA 01741 Minneapolis, MN 55402 Warrendale, PA 15096 (508) 371-0512 (800) 245-8627 (412) 776-4841 CIRCLE 226 ON FREE INFORMATION CARD CIRCLE 232 ON FREE INFORMATION CARD CIRCLE 238 ON FREE INFORMATION CARD

AEE Energy Books H&A Industries SignCraft Hill Avenue PO Box 1026 Rt 2 Box 35E 1938 Lilburn, GA 30226 Bowling Green, MO 63334 Fort Myers, FL 33901 (404) 925-9558 CIRCLE 233 ON FREE INFORMATION CARD (813) 939-4644 CIRCLE 227 ON FREE INFORMATION CARD CIRCLE 239 ON FREE INFORMATION CARD

ASM International Lindsay Publications Singing Wind Bookshop 9639 Kinsman Road PO Box 12 Ocotillo Road Box 2197 Materials Park, OH 44073 Bradley, IL 60915 Benson, AZ 85602 (800) 368-9800 (815) 468-3668 (602) 586-2425 CIRCLE 228 ON FREE INFORMATION CARD CIRCLE 234 ON FREE INFORMATION CARD CIRCLE 240 ON FREE INFORMATION CARD

Computer Literacy Bookshop MIX Bookshelf Stanford Bookstore 2590 N First Street 6400 Hollis St Ste 12 135 University Avenue San Jose, CA 95131 Emeryville, CA 94608 Palo Alto, CA 94305 (408) 435-1118 (800) 233-9604 (800) 533-2670 CIRCLE 229 ON FREE INFORMATION CARD CIRCLE 235 ON FREE INFORMATION CARD CIRCLE 241 ON FREE INFORMATION CARD

Dialog Information Service Synergetics Omega Engineering 3460 Hillview Avenue Box 809 One Omega Drive Palo Alto, CA 94304 Thatcher, AZ 85552 Stamford, CT 06907 (415) 858-2700 (602) 428-4073 CIRCLE 236 ON FREE INFORMATION CARD CIRCLE 230 ON FREE INFORMATION CARD CIRCLE 242 ON FREE INFORMATION CARD

Educational Products Real Goods Whole Earth Review PO Box 606 966 Mazzoni Street 27 Gate Five Road Mineola, NY 11501 Ukiah, CA 95482 Sausalito, CA 94965 (516) 689-8409 (800) 762-7325 (415) 332-1716 CIRCLE 231 ON FREE INFORMATION CARD CIRCLE 237 ON FREE INFORMATION CARD CIRCLE 243 ON FREE INFORMATION CARD

www.americanradiohistory.com PACKARD BELL America grew up listening to us. It still does. O AC -DC PACKMATE 286 COMPUTER 0.68 µF 270G MOTOR 1.5 Meg 1 Watt WITH HIGH RESOLUTION 110 VAC VGA COLOR MONITOR 2N6154 N4004 TRIAC N

13 V 220tIF 10052 470 pf WARNING: Extreme -- shock hazard except at touch pads!

80286 microprocessor (operates at 12 MHz). One 3-1/2" 1.44 MB floppy drive. One 5-1/4" 1.22 MB floppy drive. 30 MB hard drive.

1 MB RAM on motherboard expandable to 3 MB. High resolution monitor: 640 x 480. 256 colors. Includes VGA 14" color monitor & VGA card. IBM compatible. AT compatible. 8 expansion slots. Dual FDD/HDD controller. 2 half height drive cavities exposed.

1 half height drive cavity enclosed.

2 serial ports. 1 parallel port.

Zero wait state. 8 9 10 Real time clock/calendar. 11111 System configuration in CMOS with battery back-up. AT style 101 key professional keyboard. FIG. 4-A 10-SPEED TOUCH -CONTROL BLENDER circuit that uses the low-cost LS7314 Small footprint. chip by LSI Systems. The eleventh touch pad is for power off. Included software: MS DOS 3.3 and GW BASIC. Manufacturer's 145W Universal (pitch) power supply. Suggested Retail Socket for 80287 $3,499.00 co -processor on DAMARK PRICE: motherboard. One Year s1499 Warranty! 99 Factory New! Item No. B-2093-132142 aim Factory Perfect! Insured Ship/Hand.: $40.00 FOR FASTEST SERVICE T TOLL FREE CALL 9 volt battery 1-800-729-9000

VISA (MasterCard OtICOVEß MMMMMMIZIIMIM piezo speaker DAMARK INTERNATIONAL, INC. 6707 Shingle Creek Parkway. Minneapolis. MN 55430 2.2M Customer Service 612-566-4940 Please rush me: _ Packard Bell Computer(s) @ $1499.99 each, plus $40.00 s/h each. Item No.B-2093-132142 MN res. add 6% sales tax.

Name Address City.State Zip FIG. 5-A HIGH -QUALITY MELODY circuit. The slow decay waveforms produced will Check/MO VISA Master Card Discover create chime -like notes. Pitch, tempo, and duration are all adjustable. Card No

Exp. Date / Ph # ( Unusual book resources formed is to aggressively expose Signature I feel that the best possible way themselves to the industry trade DELIVERY TO 48 U.S. STATES ONLY for hackers to keep and stay in- journals. And the second best is

www.americanradiohistory.com through creative use of on-line ac- usual books certainly have their cess services, most especially the place. As you might have noticed, finding Dialog Information Service. mall storefronts that have a sign out DIGITAL But technical and any other un- front that says "book store" are waveform PROBLEMS

NAMES AND NUMBERS The frequency domain approach can often show problems clearly, which Adobe Systems Komacel, Inc only close examination in the time domain with exotic equipment will N Midland Ave 1585 Charleston Road 535 reveal. Mountain View, CA 94039 Saddle Brook, NJ 07662 (415) 961-4400 (201) 791-1511 CIRCLE 245 ON FREE INFORMATION CARD CIRCLE 264 ON FREE INFORMATION CARD FIG. 7 Celtec/Vycom Lazer Products Greenwood Ave & Warner St. 12741 East Caley Ave #130 Scranton, PA 18505 Englewood, CO 80155 (717) 346-8254 (303) 792-5277 CIRCLE 246 ON FREE INFORMATION CARD CIRCLE 265 ON FREE INFORMATION CARD

Ron Charles & Associates LSI/CSI PO Box 805 1235 Walt Whitman Rd time Wilmette, IL 60091 Melville, NY 11747 (708) 251-4777 (516) 271-0400 For example, a circuit used for digital CIRCLE 247 ON FREE INFORMATION CARD CIRCLE 266 ON FREE INFORMATION CARD scope evaluation appears to produce the square wave of a 4 -bit counter. The Compliance Engineering signal has a fast risetime (around 1 ns.) 629 Massachusetts Ave. Motorola and some overshoot like that found in any digital Boxborough, MA 01719 5005 E McDowell Road system. This viewed on an analog 100 MHz scope is shown in fig. (508) 264-4208 Phoenix, AZ 85008 FREE INFORMATION CARD 7. Looks conventional, doesn't it? CIRCLE 248 ON FREE INFORMATION CARD CIRCLE 267 ON

EE Times NEC 10dß 600 Community Drive 401 Ellis Street per Manhasset, NE 11030 Mountain View, CA 94039 DIV (516) 365-4600 (800) 632-3531 CIRCLE 249 ON FREE INFORMATION CARD CIRCLE 268 ON FREE INFORMATION CARD

Freedom of the Press SGS-Thompson 100 900 Tech Park Drive #8 1000 E Bell Road µv Billerica, MA 01821 Phoenix, AZ 85022 I { .í (800) 873-4367 (602) 867-6259 frequency 100MHz CIRCLE 259 ON FREE INFORMATION CARD CIRCLE 269 ON FREE INFORMATION CARD The same signal is then applied to the GoScript/LaserGo Surplus Center Spectrum Probe". (20 dB atten. added to 9369 Carroll Park Dr. #A "O" Street keep RF components within the 1015 West logarithmic range.) Two major San Diego, CA 92121 Lincoln, NE 68501 problems are visible in fig. 8. Why are (619) 450-4600 (800) 228-3407 CIRCLE 260 ON FREE INFORMATION CARD very high spectral line levels present CIRCLE 270 ON FREE INFORMATION CARD which are approximately 15 MHz. apart? The other problem, Hosfelt Electronics which can't Texas Instruments be shown easily in the photo, is the 2700 Sunset Blvd PO Box 809066 alternating amplitude of the spectral Steubenville, OH 43952 Dallas, TX 75380 line components - which indicates (800) 524-6464 that (800) 232-3200 significant low frequency CIRCLE 261 ON FREE INFORMATION CARD components are present in the signal. CIRCLE 271 ON FREE INFORMATION CARD Intel Ultrascript/QMS 3065 Bowers Ave 107 SPECTRUM PROBE Santa Clara, CA 95051 PO Box 81250 (408) 987-8080 Mobile, AL 36689 converts your scope into a CIRCLE 262 ON FREE INFORMATION CARD (205) 633-4300 100MHz spectrum analyzer CIRCLE 272 ON FREE INFORMATION CARD JerryCo 601 Linden Place Unitrode $199 direct Evanston, IL 60202 580 Pleasant Street Smith Design 1324 Harris ig (708) 475-8440 Watertown, MA 02172 Dresher, PA 19025 (215) CIRCLE 263 ON FREE INFORMATION CARD CIRCLE 273 ON FREE INFORMATION CARD 643-6340 CIRCLE 182 ON FREE INFORMATION CARD c)

67 www.americanradiohistory.com DIGITAL VIDEO STABILIZER ELIMINATES ALL VIDEO COPY PROTECTIONS often less than useless. And pub- ern Americana, Southwest Liter- lisher's catalogs carry only their own ature, lost mine lore, and an titles, many of which may be "me otherwise amazingly eclectic collec- too" or appallingly bad. tion of arcania. Since Singing Wind Instead, you really have to expose has an unlisted address, getting While watching rental yourself to sources that have a ves- there is half movies, you will notice an- WARNING : the fun. If you're not noying periodic color ted interest in stocking a wide selec- one of their kind of people, you'll darkening, color shift, un- SCO wanted lines, flashing or Electronics and tion of the best books on special never find the place. Jagged edges. This is caused by the copy protec- RXII dealers do topics. Well, maybe one hint. Go north tion jamming signals em- bedded in the video tape, not encourage As your resource sidebar for this on Ocotillo Road out of Benson, Ari- such as Macrovision copy people to use month, I have tried to show several zona it feels protection. Digital Video till about right. Then Stabilizer. RXII completely the Digital sources of unusual books that I've turn right just beyond the seventh eliminates all copy protections and jamming signals Video Stabilizer personally found of interest. Let's cow. Keep the gates the way you and brings you crystal clear to duplicate do a quick rundown... find them. pictures. rental FEATURES: movies The foremost source for hacker Tellyawhat. I'm sure I've missed Easy to use and a snap or copyrighted to install titles has to be Lindsay Publications, plenty of good sources for unusual State-of-the-art in- video tapes. tegrated circuit technol- RXII is in- who stock an amazing variety of me- books. For this month's contest, just 100% automatic - no chanical, machine shop, antique ra- tell me abbut some other genuinely need for any tended to stabi- troublesome adjust- lize and restore dio, craft, and weird science titles. useful place to find specialized or ments Compatible to all types crystal clear For automotive electronics, nobody oddball titles. Do include a mailer if of VCRs and TVs picture quality can beat SAE. And for electronic We have a The best and most excit- possible. will dozen ing Video Stabilizer in for private music, the MIX Bookshelf is first Incredible Secret Money Machine the market home Light weight (8 ounces) use only. rate. book prizes, along with an all -ex- and Compact (1 x3.5x5 ) Beautiful deluxe gift box ( Dealers Welcome ) For astronomy and space books, pense -paid (FOB Thatcher, AZ) Uses a standard 9 Volt battery which will last 1- try Frontier Space Books. For tinaja quest for two going to the very 2 years. robotics, use Educational Products. best. For all the alternate energy and self- As usual, send all of your written ToOrder: $49.95 ea + $4 for FAST UPS SHIPPING reliance, try Real Goods. For estab- me 1-800-445-9285 or 516-694-1240 entries directly to at Synergetics, Visa, M/C, COD M -F: 9-6 (battery not Included) lishment energy and conservation rather than to Radio -Electronics. SCO ELECTRONICS INC. AEE Dept. CBY7 581 W. Merrick Rd. Valley Stream NY 11580 stuff, Energy Books. For Unconditional 30 days Money Back Guarantee signmaking, it's SignCraft. For met- New tech literature CIRCLE 193 ON FREE INFORMATION CARD als and properties of materials, ASM Free data books for this month International. include the Product Selection CABLE TV It appears that two of the finest Guide from NEC on memory, mi- technical bookstores in the country cros, peripherals, and telecom DESCRAMBLER are across the street from each chips; the i486Microprocessorfrom other. So, you will want to check out Intel; and the new Semiconductor both the Stanford Bookstore and Databook and Application Notes the Computer Literacy Bookshop. from Unitrode. For a direct -mail source of most Two surplus catalogs having great technical and industrial titles, you pricing are available through Hosfelt also may want to check out Omega Electronics for electronic goodies; 1 Unit 10 + Engineering. and Surplus Center for pneumatics, Jerrold S.B. $74 $55 By far the best place I've found for hydraulics, and larger motors. Jerrold SB wrilimode $90 $70 in-depth reviews of all unusual and Compliance Engineering is an un- Oak N-12 (w/VS) $89 $65 genuinely useful books is Scientific Atlanta $109....$75 the quar- usual trade journal aimed at helping Pioneer $109....$75 terly Whole Earth Review I cannot you meet FCC and similar specs. Panasonic converter $98 $79 say enough good things about these They have a free supplement Direct 73 channel converter $79 $59 wonderful folks. Connection: Interfacing to the Tele- I try to stock my own titles and phone Network available just for We Beat Anyone's Price! only the very best PostScript titles of you. Ask for Application Note #102. 30 Days Money Back Quaranty others in my own Synergetics. Reasonably priced vacuum form- Free Catalog It seems I've always been at- ing machinery is available through Visa, M/C, COD or send money order to: tracted to what I call "Tain't Likely Ron Charles & Associates. While in- US Cable TV Inc. Dept. KCT7 McGee" publications on Tesla -was - tended for hobby modelmaking, an -alien free energy, perpetual mo- there should be lots of hacker uses 4100 N.Powerline Rd., Suite F-4 tion, Pogue carburetors, Newmann involving prototypes and limited Pompano Beach, Fl 33073 engines, and similar off-the-wall production runs. 1-800-445-9285 goodies. Although Lindsay stocks Two interesting new prototyping and honestly reviews a few of these and model materials are the Please have make and model number of the a Komacel equipment used in your area ready. titles, second and more typical and Celtec foamed vinyls. source would be H&A Industries. Free samples are available. No Florida Sales! As a final favorite of mine, Singing The bargain of the month has to It's not the intent of US Cable TV Inc. to defraud any pay TV operator and we will not Wind does specialize in the West- (Continued on page 81) assist any company or individual in doing so. 68 CIRCLE 194 ON FREE INFORMATION CARD www.americanradiohistory.com AUDIO UPDATE LARRY KLEIN, Taking care of your tapes AUDIO EDITOR

CONSIDERING THE RECENT FLOOD OF audio -video components into the marketplace and the very successful efforts made to upgrade video sound, I think it is not inappropriate to devote a column to the care and storage of audio and video tapes. Current opinion is that, given reasonable care, the audio and video tapes you made last month should be playable by your children's children-assuming that compatible machines are still available. The major causes of tape deterioration- which I'll discuss in order-are heat, humidity, dirt, stray magnetic fields, FIG. 1-THESE VIDEOCASSETTE REWINDERS will save your VCR from excess wear and and improper handling. tear. reacclimate to the indoor tempera- dozen different brands of video Heat ture before use. head cleaners on the market, most Whether blank or recorded, from reputable companies, many tapes ideally should be stored at a Dirt technicians strongly advise against constant temperature of, say, 21° Storage sleeves are designed to their use. In their view, the only way Celsius (70° Fahrenheit). The con- guard videocassettes against the in- to thoroughly clean a VCR while stancy of the temperature is more trusion of dust and dirt, and they do avoiding excessive head wear or important than its actual value, be- a pretty good job. But when a cas- damage is to return the machine to a cause large temperature swings sette is loaded into a VCR, its tape factory -authorized service center cause expansion and contraction of and internal mechanisms are some- for cleaning. My own view is that a the tape's base (backing) material. what exposed. It follows, therefore, wet or dry head -cleaning vid- That could result in its permanent that it's wise to keep the VCR (and eocassette from a reputable compa- deformation as well as oxide shed- tape -storage area) as dust -free as ny is unlikely to cause problems if ding. So, avoid leaving tapes in attics possible. It also follows that you used precisely according to instruc- or locked cars and keep them away shouldn't leave a tape "stored" in tions and only when a grainy or lost from air conditioners, radiators, the VCR unless, of course, you have picture shows that its services are heating vents, and direct sunlight. it set up for timer recording. needed. As I mentioned, head clog- There's a certain amount of oxide - ging is rare when new high-grade Humidity coating shedding from any tape dur- tapes are used. For archival storage, a constant ing the recording and playing pro- If I had followed the advice of humidity of about 15 percent is rec- cess, but the better the tape, the those who advocate factory service, ommended, but in a typical home less it sheds. Modern high-grade by now I would have paid for at least the humidity is likely to be far lower audio and videotapes are extremely seven or eight cleanings of my old in winter and higher in summer. In "clean" in this regard. Unfor- VCR (at perhaps a $50 to $75 a shot) any case, don't store your audio and tunately, the tape stock used for in addition to the inconvenience of videocassettes in a damp basement, some prerecorded audio and video getting it to and from the service and if you've been videotaping out cassettes is not as a high a quality as organization, and not having it avail- of doors on a cold day, give your it might be. able for use while being serviced. tape (and recorder) an hour or so to Although there are perhaps a Since my older machine doesn't

www.americanradiohistory.com seem to have suffered any ill effects forwarding and rewinding them at Be an FCC from years of at-home cleanings, it's least once a year. The purpose is to clear that the money saved by a prevent possible print -through of LICENSED good head -cleaning cassette more the audio track and/or adhesion be- ELECTRONIC TECHNICIAN! than compensates for any addi- tween tape layers. It seems to me tional head wear it might cause. that there is no harm in such a te- dious procedure, but before you Stray magnetic fields embark on such a long -and -winding _ Because the video picture and au- road for video, I suggest investing in Earn up to dio sound are embodied on a tape a videocassette winder, which will $30 an hour A II! Sao and more! in the form of complex magnetic speed the process and save wear patterns, anything that disrupts and tear on your VCR. those as strong ex- The Learn at home In spare time. patterns-such ultra -cautious also suggest - No previous experience needed ternal magnetic fields-should be storing audio and video tapes in No costly School. No commuting to class. avoided. Therefore, don't store just -played condition (rather than The Original Home -Study course pre- tapes close to or on top of sources rewound to the beginning, as video - pares you for the "FCC Commercial Radio- telephone License". This valuable license of magnetic energy such as loud- rental places prefer). Their reason- is your "ticket" to thousands of exciting speakers, amplifiers, and any other ing is that during normal play, tape jobs in Communications, Radio TV, Micro- electronic component that has a tension is better distributed wave, Computers, Radar, Avionics and large power transformer. A distance throughout the tape layers because more!. You don't need a college degree to qualify, but you do need an FCC License. of two to three feet from potential of the slow playing speed and be- No Need to Quit Your Job or Go To School problem areas should be more than cause video play is under direct ser- This proven course is easy, fast and low adequate. Incidentally, I've heard of vo control by the VCR, unlike cost! GUARANTEED PASS - You get your cases in which vacuum -cleaner during tape winding. Storage after FCC License or money refunded. Send for motors caused partial tape erasure, play is FREE facts now. MAIL COUPON TODAY! without rewinding the prac- so be careful when cleaning the tice followed by audio recording commanu PRODUCTIONS ' tape -storage area. studios with their open -reel master FCC LICENSE TRAINING, Dept. 90 P.O. Box 2824, San Francisco, CA 94126 tapes. However, its relevance to cas- Please rush FREE details immediately) Handling settes, audio or video, is unclear. NAME Some experts advise that stored It's also generally advised that ADDRESS open -reel tapes and audio and vid- tapes be stored vertically to avoid CITY STATE ZIP eo cassettes be "exercised" by fast - possible damage to the tape edges.

However, I suspect that the advice is simply a holdover from open -reel days when the tape "pack" would VALUE PRICING ON KENWOOD droop toward the bottom flange if the tape were stored horizontally. OSCILLOSCOPES FROM 1:15%11 The tape pack in cassettes is smaller, lighter, and better positioned by its DIGITAL READOUT Model (S-5170 enclosing shells.

DELAYED SWEEP I should admit that I tend to leave VIDEO CLAMP my tapes unexercised, sometimes CURSOR FUNCTIONS half -wound, out of their storage HIGH SENSITIVITY cases, and stored every which way. AUTOMATIC TRIGGERING And in thirty -odd years I've never experienced any audio or video HIGH RESOLUTION 12KV CRT tape problems clearly caused by my 2 -YEAR WARRANTY Coll Joseph Electronics for value quotes on all KENWOOD models. negligence. Then again, maybe I've been lucky or simply haven't KENWOOD 'The Company You've Been Listening To For Years." noticed. R-E 2 -OSCILLOSCOPE CE 40 MHz '0121i2707: 100 MHz

VERTICAL MODE CHI, CH2, DUAL (ALT, CHOP), ADD VERTICAL MODE CHI, CH2, ALT, CHOP, ADD

SENSITIVITY 1 mV/DIV to 5 V/DIV IN 12 RANGES SENSITIVITY 1 mV/DIV to 5 V/DIVIN 12 RANGES HORIZONTAL MODE A, ALT, B, X -Y HORIZONTAL MODE A, ALT, B, X -Y SWEEP TIME A 0.20 T0 0.5 5/DIV ±3%(20 ranges) SWEEP TIME A 0.51.S TO 0.5 S/div ±3% (22 ranges)

B 0.20 TO 50mS ±3%(17 ranges) B 0.50 TO 50mS/div ±3% (19 ranges) TRIGGER SOURCE VERT MODE, CHI, CH2, EXT, LINE TRIGGER SOURCE VERT MODE, CH1, CH2, EXT, LINE

TRIGGER MODE AUTO, NORM, FIX, SINGLE -RESET TRIGGER MODE AUTO, NORM, FIX, SINGLE -RESET COUPLING HF rej, DC, 1V FRAME, TV LINE COUPLING AC, HF rej, DC, TV FRAME, TV LINE

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move through the opto module, they'll intermittently break the two LAWN MOWER light beams causing the module's in- continued /rum page 47 ternal phototransistor to turn on and off. The process creates two square -

wave IN I -I and IN l-2, that have output (pin 7 of IC4-b) in the positive outputs, direction by a few volts. Capacitor C4 pulse widths that are proportional to is used to create a low-pass filter at the the speed of the chopper wheel, output stage of the D/A circuit. The motor, and drive wheel. Since one light beam is broken before the other, D/A circuitry and the manual -control FIG. 5-THE MOTOR -CONTROLLER IN 1-2 will always lead IN I -I in phase by input (J4 pin 8) provide the steering board fits in one of the motherboard's input reference to the velocity-feed- slots. 90 degrees when the motor is in mov- back loops. ing in the forward direction. Figure 8 we will discuss them shortly. A pho- shows the two square -wave outputs Velocity -feedback loops tograph of the motor-controller board from the dual opto -interrupter mod- in the re- Each loop consists of a summing i:, shown in Fig. 5. ule. When the wheel spins junction, amplifier, PWM, velocity Within the motor housing is a verse direction, the phase of the two feedback, tachometer circuitry, and chopper wheel that is. used for sensing square waves will switch. In that case, inverter/switch. Since the right and wheel (and motor) speed. The chop- the square wave at IN I-1 will lead in left velocity -feedback loops are per wheel is shown in Fig. 6. The phase by 90 degrees. That tells the basically identical, we will discuss wheel has gear -like teeth that move motor-controller circuitry if the drive the details of the left velocity loop through a dual opto -interrupter mod- wheels are moving forward or back- only. Op-amp IC4-d acts as the sum- ule as shown in Fig. 7. As the teeth ward. ming junction and amplifier. The The square -wave outputs for the left steering reference signals are coupled drive motor are fed to the motor con- to the op -amp's inverting input (pin troller board via J3, pins 7 and 8. The inverters ICI -c 13) through resistors R24-R28 and signals are buffered by OPTO flip R40. Capacitor C5 is used to create a INTERRUPTER and IC1-f and then sent to D -type low-pass filter at the amplifier's output flop IC2-a. The flip flop is used to or pin 14). After the signals are added determine motor direction; forward and amplified, they are passed reverse. Since the flip flop clocks in through R57 to IC9, a UC3637 Pulse data during the 0 -to- + 5 -volt transi- Width Modulator (PWM) IC, that tion at pin 3, 0 volts will be indicated sends PWM signals to the power at the Q output (pin 5) when the motor board for running the.drive motors. is moving forward. Conversely, + 5 volts will be at the Q output when the Also contained on the motor-con- FIG. 6-THE CHOPPER WHEEL has gear - motor is in reverse. troller board are the grass -sensor am- like teeth that move through a dual opto - on page 74 plifiers, which are shown in Fig. 4 interrupter module. continued

www.americanradiohistory.com DRAWING BOARD ROBERT GROSSBLATT, Scrambling and Macrovision CIRCUITS EDITOR

IF YOU'VE BEEN ALONG WITH US ON OUR magical trip through videoland, /OOZE /V- you've had enough basic video stuff jammed down your throat to get a high-level executive job at the local 731141/\\ network. If you've built the hard- IRE .3V- z ware as well, you're in line for the network presidency. The most im- -VOIRE 0V - portant thing you should have

picked up from everything we've FIG. 1 been doing is that the video signal is an extrer.lely complex waveform the control signals if there isn't pic- Although there's no real data with strictly defined timing param- ture there as well. I suppose that shown in the video information part eters. As with most complex things, some people are such hard-line of Fig. 1, a typical line of real video however, it's a lot harder to put it couch potatoes (now where did that might look exactly like that. The together than is to take it apart. Just come from?) that they even enjoy an thing that should be obvious in the like a jigsaw puzzle, it may take evening of staring at a blank screen. drawing is that the video informa- three weeks to build but it takes Come to think of it, some of the tion has to be placed outside the only three milliseconds to wreck. stuff that shows up regularly on the horizontal interval and it can't go Modern art aside, the only way tube isn't much better. But, then below 0 IRE units (about 0.3 volts) or you can get an image on the screen again, four hours of a blank screen above 100 IRE units (about 1 volt). A is by having all the right signals means four hours without commer- level of 0 IRE produces a black signal show up at the right place at the cials so maybe it's really not so bad and a level of 100 IRE produces right time. Leave out just one of the after all. white. required control pulses and the TV Since we now know that every- The reason that video levels are set will turn up its nose at the entire thing in the NTSC signal is pre- usually referred to in terms of IRE signal. If you don't have all of it, you defined, it shouldn't be any surprise units is that, while the signal is sup- might as well have none of it. to learn that there are rules for pic- posed to be 1 volt peak -to -peak, And, before I forget, several peo- ture information, as well. The il- some VCR's and other equipment ple have written asking where they lustration of a line of video in Fig. 1 put out different levels. The man- can get the 8284 we used as the mas- should be an old friend by now, but ufacturers calibrate them before ter clock generator. Frankly, I'm a bit this time we're going to talk about they leave the factory but, as we all surprised anyone had any trouble the picture area rather than the hori- know, stuff happens. Most video in- finding it since the chip is carried by zontal interval. puts are clamped by one means or most of the mail order houses that The basic idea behind the NTSC another so that the video signal advertise in Radio-Electronics. All I standard is the vertical division of being fed to it is chopped down to 1 can say is that even though the 8284 the 1 -volt video signal into a control volt but the ratio of picture data to isn't listed in their ads, I know for a area and a picture area. While there video data is still at the IRE standard. fact that it's part of the inventory. Just are rules for the picture information Zero IRE is defined to be roughly give any of them a call and, as the (just as there are rules for the stuff in one third of the complete peak to man said, ask for it by name. the horizontal interval), things are a peak voltage swing regardless of the lot looser when you're talking about actual voltage. A level of zero volts is The picture area pictures. Sync signals have require- always -40 IRE units and 100 IRE The sync system we've been ments covering placement, ampli- units (100% white) is always the up- studying and building is only one tude, and width, but picture signals per level of the input voltage swing. part of the 'NTSC signal - let's not are required only to meet place- Picture information can have an forget that there's no point to having ment and amplitude requirements. amplitude of slightly less than 100

www.americanradiohistory.com IRE units. That's because it starts at video you're going to see a series of cable company (that's them) to the 7.5 IRE units rather than at 0 IRE vertical bars on the screen. If you subscriber (that's us). The same sort units. The area from 0 to 7.5 IRE units want to break the lines vertically and of argument used to be used by the are reserved for what is officially re- wind up with a series of squares, phone company. I'm sure that ev- ferred to as the "set-up level." The you'll have to keep track of the eryone remembers the days when top of that (7.5 IRE units) is the black number of lines and enable the pro- adding your own extension phone threshold and the bottom (0 IRE duction of highs only on certain meant risking the wrath of the units) is the top of sync. You can see lines. It would also be a good idea to phone company. They finally got that in Fig. 2. Having that small buff- reset the entire circuit during the smart enough to drop that attitude er area is a way of acknowledging vertical interval so the squares don't and limit their sphere of respon- that things don't always work in real do a vertical creep on the screen. sibility to bringing a line into your life as nicely as they do on paper. In the interest of space, I'm going house. The cable TV companies are The 7.5 -IRE unit gap is best under- to leave the design of the circuit to still working on the original tele- stood by realizing it's just adding a you. As a matter of fact, it's time for phone standards. bit of hysteresis to the system. Real - another contest anyway so let's If you have cable TV service, it's world signals don't always pay abso- make one out of this. The rules are reasonable to agree that they own lute attention to the written NTSC simple. All you have to do is put an the signal as long as the signal is video standard. image on the screen. The ones who running through their own equip- put the most interesting image on ment. That includes their cable, the tube in the most interesting their tuner, and an argument can manner will be the winners. What even be made that they own it all the I'm looking for is slick circuitry more way to the input jacks of your VCR 7 SIZE 1 oIRE than art but I'll take both into ac- or TV. Once the signal gets into your 1lllll count when judging the entries. stuff however, as far as I'm con- Since there's an artistic side to this cerned, it's yours. and the be- If you modify your television to ho P/ZoNTAL ß/1N, /Át contest, difference /,Y//Cì?OS.CCit/O5 tween garbage and gorgeous is in unscramble cable signals, that FIG. 2 the eyes of the beholder, there will should be nobody's business but be several free subscriptions to Ra- yours. And if that still seems to be Making pictures dio -Electronics available. questionable, let's suppose you If you're into abstract impres- were able to make some kind of sionism, it's really easy to make Scrambling pictures optical screen that went in front of video appear on the screen. The Now that we know how video is the TV and unscrambled the pic only requirements you have to fol- made, it's worth spending some ture, how could the cable compa- low are to gate the picture signal time to see how it's unmade. Of nies complain about that? And if you with sync and limit the amplitude to course I'm talking about some of had built a device that scrambled the upper100 IRE units. I don't know the stuff that the friendly folks at clear reception, you can bet your what you'll see on the screen but your local cable company do to the bottom dollar that the cable compa- the chances are that if you take pic- images they send to your house. nies wouldn't care about that either. tures of it you'll be able to sell them Unless you've spent the last couple The point I'm making is simple: if for some outrageous amount of of years with the fish faced people of the cable company doesn't want me money. However, if you're into Neptune, you're aware of the nasty to watch something I haven't paid structure, it's going to take a bit art of video scrambling-both on for, don't put the signal on the line more work to have something rec- cable TV and commercial video- in the first place. The cable compa- ognizable show up on the screen. tapes. ny argument that anything I do to If you've been around since we Let's take these one at a time. unscramble the picture, even inside started this video stuff, then you al- Cable companies make extra my own TV, is a theft of service, is ready know enough to make some- money selling subscription services covering up the fact that it's cheaper thing appear on the screen. What's and most of them are scrambled to for them to scramble the signal than key here is exactly what's meant by keep you (at least in theory) from it is to send it only to people who the word "something." Getting a being able to watch them without pay for it. screen full of bars or dots is possible paying. Before we get into what they I must have had this discussion with a handful of standard parts. do to video, I want to make a couple with just about everyone I know and The approach to the design is sim- of philosophical points. I'm interested in finding out what ple since it's really the same as the The people at the cable compa- you think of it. Write in and let me one we went through when we were nies seem to go absolutely non-lin- know what you think. designing the hardware to generate ear whenever someone builds their We'll get to the basics of video sync. own descrambler and watches their scrambling next month. First, let's The simplest case would be a se- stuff without paying. As far as I'm move on to another unpopular vid- ries of vertical bars. All that's needed concerned, any cable company ex- eo topic: Macrovision. is circuitry that goes high and low at ecutive who thinks that way is full We've all been hounded by Mac- c periodic intervals and is gated by of...errors in judgment. rovision and had to live with copies horizontal sync. If it puts out highs At a certain point on the cable, that blink constantly when they're 03 at the same place on each line of signal ownership transfers from the viewed. Since there's lots of easy to

www.americanradiohistory.com get (and legal) equipment around to signal in order to maintain negative LAWN MOWER beat Macrovision, I don't see any feedback; that inverted signal is pro- reason other than greed for the fact continued from page 71 duced by IC4-a. that it's still used. If you want to make copies of tapes that have been The square -wave signal IN I -I is Pulse -width modulators infected with Macrovision you can tapped off IC1 pin 5 and sent to IC5, a The pulse -width -modulator func- buy (or build) circuitry to eliminate frequency -to -voltage converter that tion is performed by two UC3637 it, but there's a much easier way to produces an analog voltage that repre- PWM IC's, IC9 and IC10. Pins 9 and do it, and it shouldn't take you more than a few minutes to make Mac- rovision a thing of the past. +5 LEFT Since the idea behind Macrovi- o J3-10 sion is to put pulses in the vertical IC19 0PB822S interval that confuse the AGC (Auto- rrK 7 IN 1-1 matic Gain Control) of the VCR used o J3-7 to record the copy, all you have to do is locate the AGC trimmer in the

VCR and turn it down. As soon as IN 1-2 you kill the AGC, the Macrovision i\ rK o J3-8 pulses won't have any effect at all. People make arguments that you TO MOTOR - need AGC to protect the video 'CONTROLLER the RIGHT BOARD circuitry in the VCR, but the video 8 IN 2-1 output of most consumer equip- o J3-6 ment is clamped to about one volt PINOUT so the chances are that you can live 0PB822S -7 very well without it. If you're really IN 2-2 not sure about killing it completely, J3-5 move the trimmer to the front panel I of the VCR. Most VCR's use DC con- IC20 OPB822S trol lines so there's not even a noise * a J3-9 problem by adding some wire and a potentiometer to the circuit. FIG. 7-THE OPTO -INTERRUPTER MODULES keep track of wheel movement. If you're nervous about that, re- member that some VCR's don't get messed up by Macrovision. The reason is that either their AGC has been IN 1-1 turned way down, isn't working, or isn't there. Save yourself some money by getting the service manual for your VCR and making the IN 1-2 adjustment yourself. It's easy to do, and, once you've done it, you probably won't see any difference in the i way the VCR behaves and you'll more than likely forget about it.

Macrovision was designed to IN 1-1 keep people from making and selling pirated copies of videotapes. Since it's so easy to beat, there's no reason for keeping it around. The IN 1-2 real protection for the people selling commercial tapes is the obvious difference in quality between the i original and the copy. FIG. 8-WHEN THE LEFT WHEEL GOES FORWARD (a), pin 5 of IC2 is at 0 volts, and when Macrovision makes commercial the left wheel goes in reverse (b), pin 5 is at 5 volts. tapes more costly to produce and more expensive for the consumer- sents wheel velocity from the square - 11 are the input to the PWM IC's, pin and that's all it does. It was a stupid wave frequency. The analog switch 4 is the "forward" output signal, and- idea when it first appeared, is even IC8, which is controlled by IC2-a, is pin 7 is the "reverse" output signal. more stupid now, and it's time to get used to select the forward and reverse When the left wheel is moving for- rid of it. velocity -feedback signals. When the ward, the analog input voltage to pins Write letters, sign petitions, and motor spins in reverse, the velocity - 9 and I1 will vary between +0.7 volts I'll talk to you next month. R-E feedback loop requires an inverted continued on page 88

www.americanradiohistory.com ÇOMPU, ERIGESi

BUILD A SOLID-STATE EDITOR'S DISK DRIVE W0RI- nag BENCH. Letters

Several items in recent columns have provoked questions from readers. Following are my responses. M. Delez of Juneau, AL asked MARK HATTEN for clarification on what I meant by stating that the number of jobs in hardware servicing would shrink (see Editor's Workbench, April 1990, p. 70). Mr. Delez is Retain important PC data with seriously considering a career in this inexpensive battery -backed RAM disk. computer and audio/video servicing, and wonders what he should do. As stated in the article, I was talking about component -level Wouldn't it be nice if you PC board is available, as are com- servicing (and R&D work). Per- didn't lose memory con- plete kits and assembled units. haps I should have made it clear- tents every time you turned off The complete assembly -language er that higher-level servicing- your PC? And wouldn't it be nice source code for the RAM disk is board swapping and the like- to have a RAM disk that didn't also available, allowing custom will continue to be a high -activity tap into your regular memory, modifications. sector of the job market. whether conventional (0-640K), A. Kusnevick of Paxton, IL extended (above 1 MB), or ex- Hardware overview asked for clarification on the panded (bank-switched beneath The circuit consists of three ROM -scan routine that a PC 1 MB)? main sections: the RAM array, BIOS executes when booting If you think that either would the bus interface circuit, and the (discussed in conjunction with be nice, then you'll be interested battery backup circuit. Figure 1 Annabooks' PromKit, in the in our static RAM disk. It's a full- shows a block diagram. March 1990 Editor's Workbench, length card for any 8- or 16 -bit The static RAM portion con- P 72). In particular, he wondered expansion slot; you can install sists of a maximum of sixteen where the byte that specifies the 32K -512K of static CMOS RAM's 32K x 8 CMOS static RAM's number of 512K blocks of memo- on the board. The board has (SRAM's), divided into two ry is located. In a ROM that is to provision for an optional battery banks. The address and data become a BIOS extension, the backup system so the card will lines of all SRAM's in both banks first byte contains 55h, the sec- retain its contents even after the are driven by IC1, an 8255 config- ond byte contains AAh, and the main system loses power. That ured as a triple parallel port. Port third contains the length spec- capability could be useful in re- A drives the low-order address ifier, which specifies the number mote data logging or industrial lines (AO-A7), Port B drives the of 512 -byte blocks in the ROM. use. high -order address lines The fourth and fifth bytes con- You can build the board for well (A8-A14), and Port C drives the tain the address in the ROM under $100, not counting the data lines (DO-D7). where the initialization routine cost of the RAM. A double -sided continued on page 79 is stored. If the checksum of all

www.americanradiohistory.com bytes in the ROM equals zero, the Fun with Math ous types of calculatior>In- BIOS saves its current location stallation consists sim of on the stack and calls the init copying the files to your working routine, which should end with a Derive is simply amazing. In disk. FAR RET to continue the boot the company's words, "De- The program works using an process and turn control over to rive is a menu -driven symbolic amalgamation of Microsoft Word COMMAND.COM. math system for personal com- style menus and WordStar key- Another reader took me to task puters. Derive does numerical stroke commands. Command for my statement in the April and symbolic equation solving, menus appear near the bottom of 1990 column (p. 70), that few of exact and approximate arith- the screen; you execute a com- the modern generation of word metic, calculus, trigonometry, mand by highlighting it and processors allow you to type and and matrices. Derive Plots ex- pressing the Enter key, or by format equations in a quality pressions in 2D and 3D on mono- pressing the capitalized letter in manner. He included a sample chrome and color graphics the command. printout of the same equation monitors." You use the Author command shown in the magazine as ren- One might add that it does all to type in and edit expressions. dered by WordPerfect 5.1. My ex- that without requiring a 386, or a Each expression is numbered; cuse is simply the fast -changing math coprocessor, or lots of mem- expressions scroll up the screen character of this business; I ory. A PC compatible, 512K of each time you add a new one. You wrote that column shortly before RAM, and a single floppy are all can't edit an expression after WordPerfect 5.1 was released. you need; a graphics display is pressing Enter, but various edit- You may also be interested to also nice for viewing plots. Her- ing commands allow you to copy know that Ventura Publisher cules, CGA, EGA, VGA, and sev- parts of previously entered ex- with the Professional Extension eral other formats are supported. pressions into the current one. has an equation editor. So does Derive also runs on the NEC And the Build command allows Word for Windows, which also PC -9801. The program will run you to build up a complex expres- has a BASIC -like language that faster on faster machines, of sion from previously entered allows you to solve equations as course, but it won't use more ones. well as display and print them. than 640K of memory or a After entering an expression, On a related note, I just re- coprocessor, even if either or both you can simplify it, factor it, ex- ceived an advertisement for a happen to be present. pand it, solve it, plot it, or save it. program called Exact that loads The following are several exam- Of course, you can also load pre- as a TSR and pops up within your ples of what Derive can do. (Solu- viously saved expressions. word processor. The program al- tions will be presented below.) Derive includes several fea- lows you to see expressions as Compute n to 70 decimal tures that simplify expression you type them, and apparently to places. entry. For example, you don't use your word processor to print Simplify algebraic expressions have to enter an asterisk to indi- them as well. More than twenty (X +1)1(1- X2). cate multiplication. Variables are word processors are supported. Factor large numbers normally a single letter, but you Contact Technical Support Soft- (987654321) can configure the program to use ware, Inc., 72 Kent Street, Perform complex -number multi -character names. Varia- Brookline, MA 02146 (617) arithmetic manipulation bles and constants can be desig- 734-4130 for more information. Find symbolic limits, do dif- nated by the Greek letters in the If there is sufficient reader inter- ferentiation, find Taylor series, IBM PC character set by pressing est, I'll get a copy of the program manipulate vectors and ma- an Alt -key combination (e.g., Alt - and check it out. trices, etc. P for n). Of course, displaying and Solve just about any computa- Derive includes all common op- printing equations is only icing ble equation to just about any de- erators and functions (+ , - , *, the cake. The real work consists sired degree of precision. , exponentiation, log, In, sqrt, of deriving the equation, making Plot just about any equation of abs, sin, cos, tan, cot, sec, csc, the calculations, and plotting the one or two variables. max, min, RMS, VAR, STDEV), results. And that leads us to a Generate an expression in a and numerous others. You can really neat software package form suitable for inclusion in any also write your own functions, called Derive. BASIC, FORTRAN, or Pascal pro- and declare constants to be used gram. in calculations. And that just scratches the Internally, Derive stores every surface. rational number as an integer or a ratio of integers. Irrational Features numbers (e.g., SQRT(2)) are Derive comes on a single floppy stored in symbolic form. You can disk; the executable file is about force Derive to compute results in 227K. The disk also includes sev- exact, approximate, and mixed eral sample files containing vari- modes. In exact mode, all com- ous expressions useful for vari- putations are done using integ- 76

www.americanradiohistory.com ers and symbols, so there are no round -off errors. In approximate mode, irrational numbers and fractional results of rational operations are rounded. You can set the number of decimal places after which rounding occurs. So if you really want to know what 7U to 500 decimal places is... In mixed mode, rational numbers are computed exactly, while irrational numbers are accurately approximated. Exact mode provides the most precision, but requires the most memory; approximate mode computes fastest and uses the least memory. You can also specify separately the display mode (rational, decimal, scientific, or mixed; and number of display digits), and number base. For the latter you FIG. 1 can specify different values for input and output, thus allowing 2 2 Derive to function as a number 21: + x + U base converter. Derive accepts number base values between two 2 \ and thirty-six. 72: 7.x +2x+2; ._; You can plot any one- or two - 23: x + y variable equation. A single varia- 2D 2 ble gives a plot; two variables 24: x + y give a 3D plot, as shown in Fig. 1. In either case you can alter sev- i

eral parameters to vary the ap- 2s: x pearance of the plot, including scale, number of "tick" marks on the axes, and viewing angle of a 3D plot. It's particularly fascinat- 26: ->" ing to view a 3D plot from dif- --_` ferent angles. Unfortunately, De- r - rive includes no print module, so 27: to print a plot, you'll have to rely

on a third -party screen -print UMMAHD: lgebra Center Eye Focal (;rids Hide Length Options Pint Quit Win.dou utility. Zoom Derive's initial screen is where .enter x:0 :0 Length x:10 :10 Derive 3D-ilot you enter expressions and where FIG. 2 Derive displays results. If you choose to plot an expression, De- rive switches to another screen. Using Derive metical expressions. Confidence However, you can split the screen To say that Derive can do all of grew quickly, so I tried some al- into several windows, each of those things does not in the least gebra. I remembered plotting which may be either an expres- say how much fun it is to use the various equations (y = x2, y = x3, sion window or a plot window. program. And it's obvious that etc.) by hand in high-school al- Figure 2, for example, shows a you can have fun with Derive, re- gebra. So I typed in a simple three -window screen at VGA res- gardless of your prior mathemat- equation and issued the plot olution. Window 1 contains sev- ical training. You might also command. Instant gratification. eral expressions; note that ex- learn something in the process. Since it was so easy, next 1 tried pression 27 (y/x) is highlighted; In playing with Derive, I fol- variations on basic themes that is the current expression. lowed the basic sequence of my (y=x2+1, etc.). In that way I Window 3 shows a 3D plot of that mathematical education. To start could see instantly how changing expression, and Window 2 shows learning how to use the program, different constants and variables a 3D plot of expression 26 (x/y). first I tried some basic arith- affected a given type of equation.

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Then I was off into trigonometry. First it was sin (x). Next was 2 Exploring Math With Derive copy of this book should be high - items..CD« sin (x). Then sin x2. You get the Derive comes with a user's priority idea. manual that is really a reference With 3D plots, you could easily guide for those who already know ITEMS DISCUSSED spend hours trying different what they are doing. If you're in- Derive ($200), Soft Ware- equations, different viewpoints, terested in Derive from an educa- house, Inc., 3615 Harding Ave- etc. Even my wife, a decidedly tional point of view -either for nue, Suite 505, Honolulu, HI non -mathematical person, got yourself or for someone else - 96816. (808) 734-5801. involved. "Let's try just one you'll want to check out Explor- CIRCLE 246 ON FREE INFORMATION CARD more..." The point is that Derive ing Math from Algebra to Cal- is a superb educational tool. It's culus with Derive, A Mathemati- Exploring Math from Algebra also a serious and powerful tool cal Assistant. The author is a to Calculus with Derive, A for scientists, mathematicians, professor of mathematics, and it Mathematical Assistant, by Je- and engineers. It's therefore is obvious that he sincerely rry Glynn, published by Math - highly recommended. wants to find ways of teaching Ware, 604 E. Mumford, Urbana, Here are solutions to the ques- people about math, not just the IL 61801. tions posed above. wizards, but the rest of us as well, 1. 3.141592653 589793238 and that he thinks Derive can as- If there's a pain in 462643383 279502884 sist the process. The book is ex- your chest, be a pain 197169399 375105820 tremely friendly in both the way it in the neck. 974944592 307816 is written and in the way it is laid 2. -1/(X-1) out. Complain to a doctor. 3. 32 x 172 x 379721*CD4 Chapter 15 of the book describes how the author has used Derive to teach math to students at various levels, including first - Chest pain could year calculus students, first -year be a sign of heart algebra students, fifth graders, disease. The sooner you see and first and second graders. Se- a doctor, the better your riously. How many pieces of soft- chances for life. ware have you seen that could be used by graduate engineers and first graders? If you're still in Heart Association school, know someone who is, or ÓAmerican need a brush -up, Derive and a

www.americanradiohistory.com RAM DISK +5V continued from page 75 BACKUP STATIC RAM ARRAY POWER o CIRCUIT A 8255, IC2, drives the IC19-IC26 second IC2 chip select () inputs of all 8255 SRAM's. Port A drives IC 11-IC 18, i BATTERY IC11- IC18 Port B drives IC19-íC26, and TC Port C is not used. PC EXPANSION 1 AO A8 The bus interface consists of a BUS -A7 -A14 DO- D7 group of buffers and gates that isolate the circuit from the PC expansion bus, and they're also BUS C BUFFERS PORT A I PORT B PORT used to decode a set of I/O port AND addresses for passing data and DECODERS ICI control information. IC3- IC10 8255 The battery -backup circuit consists mostly of several diodes FIG. 1. THE STATIC KAM DISK consists of three major subsystems: an array of as that isolate the optional battery many as sixteen 32K CMOS static RAM's, a bus -interface circuit, and a battery -backup from the PC's power source. We'll circuit. discuss the hardware in more detail next time. CII text file; each driver that DOS block driver deals with informa- is supposed to load must be spec- tion in larger chunks called Software success ified on a separate line in the file. blocks. The size of the block can Success for the PC has come (CONFIG.SYS also specifies sev- vary within certain limits set by about in part because of the ex- eral operational parameters par- DOS. pandability of the system. A good ticular to your machine; see your Examples of devices that use part of that versatile expan- DOS manual for details.) character drivers include the se- dability is due to the concept of The structure of a device driver rial and parallel ports. Examples the device driver. line in CONFIG.SYS is as follows. of devices that use block drivers A device driver provides a Spaces are shown for clarity, but include the floppy and hard disk means of adding special features must not be included, except be- drives. to DOS in such a way that those tween the name of the driver and Generally speaking, a block features appear to be an integral the optional parameters. driver can operate more effi- part of DOS. In fact, DOS itself DEVICE = [drive:][\PATH\] ciently than a character driver, comes with several built-in de- [DRVNAM][PARMS] because there is less overhead in- vice drivers. First comes the phrase DEVICE volved in each transfer of infor- ANSI.SYS is a device driver = . Then comes an optional drive mation to or from the device that provides a standard way of and an optional path and sub- controlled by the driver. With dealing with the display system. directory where the driver is some physical devices (disk driv- DRIVER.SYS is a device driver stored. If no drive is specified, the es, for example) you know that that lets you add high -density boot drive is assumed. If no path each time you request some in- floppy disks to older machines, is specified, the root of the boot formation, you'll get, say, 512 and to refer to the same physical drive is assumed. bytes. disk drive by several different Next is the name of the driver However, you can't always use a drive letters. itself. The name must follow nor- block driver. With a serial port, VDISK.SYS is a device driver mal DOS file -naming conven- for example, you can obtain only that emulates a disk drive using tions: a name with a maximum of a byte at a time. The SRAM disk either conventional or extended eight characters, plus a three - could have been implemented as memory. character extension. Common either a character or a block driv- Manufacturers of special extensions include SYS and BIN, er but, for the sake of efficiency, equipment often supply their but neither is required. Last has been implemented as a block own device drivers. For example, come any optional parameters driver. network interface cards, CD- the driver might require. ROM drives, and some types of As you've probably guessed by Driver components hard disks require device drivers. now, the SRAM disk uses a device A driver consists of three main What all device drivers share is driver to talk to DOS. components: an initialization the fact that, if a driver is to be routine, a strategy routine, and used, it must be loaded from disk Types of device drivers. an interrupt routine. every time a PC boots. How does There are two types of device The initialization routine is DOS know which device driver or drivers: character and block. As generally called once, when DOS c drivers to load? Via the CON- the names suggest, a character loads the device driver. Its job is to set up pointers to the BIOS FIG.SYS file. driver deals with information co CONFIG.SYS is simply an AS - character by character, and a parameter block (BPB) and to the 79

www.americanradiohistory.com end of the driver in memory. In addition, it must initialize the TABLE 1-DEVICE HEADER hardware as required. The ini-

tialization routine is usually lo- nexdev DD 1 cated last in the device driver file, attribute DW 02000H so that after it does its job, the DW STRATEGY system can reclaim the memory DW INTERRUPT that was formerly occupied by DB 1 ; number of devices that driver. DB (7) DUP ; used for char name The task of the strategy routine ; if char driver is to get a pointer to the DOS request header. The DOS request header is an array of bytes that variable, whose value depends on The last entry is an eight -byte communicates what type of ac- the type of device. Our driver field that is used differently for tivity DOS is trying to request uses a value of 2000h, which is block and character devices. For from the driver. The address of the setting for a non -IBM block a character device, you would as- the byte array is passed to the device. If you run CHKDSK on sign a name like CON, PRN, driver using register pair ES:BX. the RAM drive, it returns a Proba- LPT1, etc. For a block device, the The interrupt routine is what ble non -IBM disk warning be- first byte contains the number of does the actual work. It can per- cause of that value, but otherwise physical devices that are being form various types of operations, functions normally. controlled by the driver, and the some of which are mandatory for The next two entries are the ad- remaining seven bytes are un- block drivers, and others for dresses of the strategy and inter- defined. character drivers. We'll discuss rupt routines. some of the more important oper- The BPB ations now Another important data struc- MediaCheck detects whether ture in a device driver is the BIOS the storage media was removed Parts List parameter block, or BPB. The or tampered with. Bui1dBPB BPB is a data structure that tells (Build BIOS Parameter Block) Resistors DOS everything it needs to know All resistors are 1/2 -watt. 5%, unless deals with that occurrence. For otherwise noted. about the format in which infor- example, DOS calls Bui1dBPB R1-R5 4700 ohms mation is stored on the specified whenever it detects that a floppy R6-R21 22,000 ohms device. The BPB is located in the disk has been changed. In our first sector of a disk, and it in- driver. MediaCheck always re- Capacitors cludes several items, as shown in turns an OK sign to DOS. Be- C1-C16 0.01 µF polyester Table 2. cause of that, Bui1dBPB will be C17 10 µF. 10 volts, The first item in the BPB con- called only once, when the drive electrolytic tains the number of bytes per is initialized. sector. The next item specifies The input Semiconductors and output routines Dl, D2 1N914 switching the number of sectors per cluster. pass sectors of data to and from diode If you're unfamiliar with the term the disk. They use a buffer area ICI, IC2 8255 programmable cluster (also known as the alloca- specified by DOS in the request peripheral interface tion unit), it specifies the small- header. The number of bytes per IC3 74LS245 est number of sectors that can be transfer can not exceed 64K (the bidirectional bus buffer allocated to store a file. For exam- IC4, IC5 74LS244 octal maximum size of a memory seg- bus driver ple, if ten clusters were allocated ment). If a file is larger than 64K, to a file, BPB IC6 74LS138 three -to - and if the defined DOS will read or write the file in eight line decoder four clusters per sector, then the 64K chunks until the entire file IC7 74LS85 four-bit file would consist of forty sectors. has been transferred. comparator Even if a file is only a single byte IC8 74LSO4 hex in length, it requires a full cluster Structure of a driver inverter on the disk. IC9 74LS00 quad Every device driver has a device NAND gate Different versions of DOS use header that occupies the first few IC10 74LS08 quad different cluster sizes. DOS 3.3 bytes of the file. Our device head- AND gate generally allocates four sectors er is shown in Table 1. The first IC11-IC26 43256-10 Static per cluster (depending on overall entry (Nexdev) is there to provide RAM disk size); DOS 2.x allocated 8 a means of letting DOS link each sectors per cluster. device driver to the next. DOS Other Components The SW1 four -position DIP default allocation unit in fills in the links as it loads each switch the static RAM disk is one sector/ driver; the last driver in the chain B1 four AA cells, cluster, but you could alter that ha's - 1 (FFFFh) in the Nexdev with holder (optional) value to be any power of two (2°, field. 2' 23, etc.). The next entry is the attribute The next item in the BPB is the 80

www.americanradiohistory.com HARDWARE HACKER TABLE 2-BIOS PARAMETER BLOCK continued from page 68 BPB EQU $ BPB_SS DW 512 ; sector size in bytes be Jerryco's stock #79106 copy -ma- BPB __AU DB 1 ; sectors per cluster chine chassis. This is a wide dual -bin BPB_RS DW 1 ; sectors for boot sector input feeder and registration assem- 1 ; FAT tables BPB_NF DB # of bly for $10.50. As is, its a great elec- ; entries BPB_DS DW 16 # of Directory tromechanical treasurer trove. With BPB_TS DW 1024 ; # of total sector hacking effort, BPB_MD DB OFEH media descriptor some stupendous you might convert it into a fake Kroy BPB_FS DW 4 ; # of sectors/FAT(S) ;BPB_ST DW 00 These variables would be Kolor machine, an automatic dual ;BPB_NH DW 00 ; drive. bin laser feeder, or find some :BPB-H5 DW 00 used for a real disk unique robotics applications for it. BPB_PRT DW BPB ; Pointer to this table Arlin Shepard of Lazer Products tells me he has at long last found a few more Canon fusing units. We number of sectors reserved for looked at these several columns ago the boot sector. The boot sector of for Kroy Kolor, lamination, and for the BPB contains a short pro- Ordering Information dry -film printed -circuit bonding. gram that starts the process of Note: The following are available Adobe Systems has released their loading DOS from disk. DOS it- from new black book, otherwise known self contains the remainder of Hatronics as the Adobe Type I Font Format. the loader program. 145 Lincoln Street This has all of the previously secret The next entry specifies the Montclair, NJ 07042 insider stuff on their encrypting, number of File Allocation Tables (201) 783-7264 compacting, and the hinting of (BBS, the I have a (FAT'S). DOS uses the file alloca- (201) 245-6614 join high -quality typography. do tion table to keep track of which Hatronics conference) few copies on hand here if you need sectors have been used, which Bare PC board $50 one. wi-h OK RAM $90 are free, and which are physically Kit Turning to my own products, I've Kit wih 128K RAM $155 put together a special new damaged. DOS normally main- RAM $220 Kit wilt 256K Lancaster Classics package of six of tains two copies of the FAT; to Kit wi`h 5I2K RAM $322 my finest hardware books plus that conserve space, our driver main- Asserr bled and tested unit, OK $135 Hacker ll re- tains one. Asserr bled and tested unit. complete Hardware Next in the BPB comes the 256K $255 print set which covers everything number of directory entries. This Asserr bled and tested unit. that has appeared in these Radio - value specifies the number of files 512K $395 Electronics columns. All orders add $10 for shipping and that can be present in the root Finally, I've got a new and free handling. .. New jersey orders add 6% which includes doz- directory of a disk. (Subdirecto- sales :ax. mailer for you ries are actually files, so the ens of insider hardware hacking se- number of subdirectories is lim- cret sources. Write or call for info. ited only by the available disk As always, this is your column and space.) DOS 3.3 typically allows is a field that specifies the you can get technical help and off- 512 directory entries; again, to number of sectors that must the-wall networking per that "Need conserve space, our driver allows be allocated to each copy of the Help?" box. The best calling times 16. FAT. are weekdays 8-5 in Mountain Stan- The next BPB entry contains Several other fields in the BPB dard Time Let's hear from you. R -E the total number of sectors con- are defined for use with physical tained on the disk. This value disk drives, including the represents the total size of the number of sectors per track, the "Make a promise disk, including space occupied number of disk heads, and the earth" by boot sectors, FAT'S, etc. In our number of hidden sectors. Our to the case, the total number of sectors driver does not need to use any of When you plant a tree you make (TS) can be determined from this those fields. life better for your children and for formula: Obviously, the subject of device the future. Join me and plant a tree. of drivers is complex; for detailed For your free brochure, write: TS = (32768/512)*(number Trees for America, The SRAM's) information, the best work that is called National Arbor Day The next entry is called the me- was found by the author Foundation, Nebraska dia descriptor; it specifies the Writing MS-DOS Device Drivers City, NE 68410. type of media being used, the by Robert S. Lai. number of sides, etc. Our driver Next time, well discuss hard- John Denver for ware operation in detail, and The National uses the code for a single -sided Foundation floppy -disk drive. then show how to build and ini- Arbor Day Following the media descriptor tialize the drive..$

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TOCOM 5503 V.I.P. "turnon" module; unscrambles Address City "all channels." Easy hookup. $39.00. MIKE, Box State Zip Phone Number ( 743, Oldsmar, FL 34677. COD Visa Mastercard UNIVERSAL CRT adapter, tests/restores every Cashier's Check Money Order CRT on the market... without ever buying another Acct # Exp. Date socket for your CRT tester. Fits all makes/models. Moneyback guarantee. Patented kit w/setup book Signature $63.95 Canada, US $69.95. 1990 setup book $12.00. Chargecards. DANDY MFG. CO., 2323 FOR OUR RECORDS: Gibson, Muskogee, OK 74403. (918) 682-4286. DECLARATION OF AUTHORIZED USE - I, the undersigned, do hereby declare under penalty of perjury now in the future, will only be used on cable TV systems with proper DESCRAMBLERS cable TV converters dis- that all products purchased, and - - officials In accordance with all applicable federal and best quality, guaranteed, free cat- authorization from local officials or cable company count low prices, LAWS PROVIDE FOR SUBSTANTIAL CRIMINAL AND CIVIL CNC Concepts, Box 34503, Mpls., MN state laws. FEDERAL AND VARIOUS STATE alog, PENALTIES FOR UNAUTHORIZED USE. 55434. 1 (800) 535-1843. OBSOLETE electronics. Do you have equipment, Dated- Signed parts for sale? Install it on our National Data Base. We'll find buyers. Send list of 100 items or less along with $4.00 to OBSOLETE ELECTRONICS, PO Box 3130, Lubbock, TX 79452. Pacific Cable Company, Inc. CABLE descramblers, Tocoms, Tocoms, Tocoms, 73251/2 RESEDA BLVD., DEPT. R-7 RESEDA, CA 91335 $199.00 each or 10 @ $175.00 inc. remote, Oak RTC56 with remote $150.00 or $135.00 in lots of 10, (818) 716-5914 No Collect Calls (818) 716-5140 Jerrold -400 DIC $125.00 or $110.00 in lots of 10, MLD-1200, Tri -Bi, SA -3-B, Zeniths in stock, same day shipping, COD ok, (206) 896-6837. IMPORTANT: WHEN CALLING FOR INFORMATION Please have the make and model # of the equipment used in your area. Thank You 83

www.americanradiohistory.com WIRELESS CABLE RECEIVERS 1.9 TO 2.7 GHz BUILD this five-digit panel meter and square -wave generator including an ohms, capacitance fre- 30 CH PARABOLIC DISH SYSTEM 5173.90 and quency meter. Detailed instructions $2.50. AMAZING 30 CH ROD ANTENNA SYSTEM $193.90 BAG- 30 CH CRYSTAL CONTROLLED NALL ELECTRONICS, SCIENTIFIC & ELECTRONIC SYSTEM S294.95 179 May, Fairfield, CT SUN MICROWAVE INTL. INC. SEND $1.00 FOR 06430. P.O. BOO $34522 PRODUCTS CATALOG ON THESE MINIATURE FM Tracking PHOENIX, AZ. 85067 AND OTHER FINE transmitters! transmitters! Voice disguisers! Bug detectors! Phone Devices! GRA1 - ANTI GRAVITY GENERATOR $10.00 1602! 230-0640 VIDEO PRODUCTS QUANTITY DISCOUNTS LIFETIME WARRANTY More! Available in kits or assembled! Catalog $2.00: ,ad LC7 - 40 WATT BURNING CUTTING LASER .. $20.00 VISA'MCiAME X THE XANDI ELECTRONICS, Box 25647, Dept. 60F, RU84 - HI POWER PULSED DRILLING LASER $20.00 MEMBER OF BETTER BUSINESS BUREAU

FINALLY! CABLE TV An interesting and worthwhile project. This EASY - TO -BUILD circuit lets you use any regular TV set as TB -3 (Tri -Bi) or SA -3 a simple OSCILLOSCOPE. DETAILED PLANS: $7.95 No modifications to TV! Tiny, 9v battery powered. Quantity Prices TV -SCOPE Goes anywhere! Order now! PENN RESEARCH, Box 3543 Ask for our FREE CATALOG 10 20 Williamsport, PA 17701 of other plans end kits!

SURVEILLANCE. Audio/video equipment - De- bugging, industrial or private. 500 item catalog One tree can make $7.00. SECURITY SYSTEMS, 3017G Hudson, $48. $43. 3,000000 matches. New Orleans, LA 70131. Each Each FM wireless microphone, 3 mile range, plans $4.00. FM, PO Box 4383, Bloomington, IL 61702-4383. 50 100 DAZER defense device kit! $44.95. Exciting unique kits catalog $1.00. QUANTUM RESEARCH, 17919-77 Avenue, Edmonton, Alberta T5T 2S1. ELECTRICITY from the sun! Learn to make home- made solar cells. Pennies each. $5.95, W.C.N., $39. $35. 3283 Belvedere, Riverside, CA 92507. Each Each MUSICIANS, 0-999 beats per minute digital metro- nome; plans $15.00 check to: NEUTRONICS, 107 Elmdorf, Rochester, NY 14619. Hours open 10:00 am to 4:00 pm Eastern time One match can burn Minimum order 5 units 55.00 ea. 3,000,000 trees. BUILD robot from outer space! Plans $11.95, details free. ROBOT WORKS, Box 1979, Colorado Dealers wanted. We ship COD. Springs, CO 80901. King Wholesale DIGITAL V.O.M./D.P.M.

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R New solid-state and digi al TV sets, stereos, and v'd- eorecorders are tougher to repair than old-fashioned tube type sets and require special training for the service tech- Our huge inventory of over Cercul added to your phone always silences 1st mg. When you send secret nician who works on them. is sequence of -silent rings' - our phone answers serf allowing you to eaten in Only a few states have laws 15,000 different items on room while still on the ook! You are not detected! Works like a normal requiring competency tests constantly monitored and phone all times. Free hard to find TCM 1506 ring detector chip included for licensing technicians who other re -stocked to virtually with step by step instructio s. Send $13.95 to: repair consumer electronics, r. 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CIRCLE 87 ON FREE INFORMATION CARD 85

www.americanradiohistory.com THE ELECTRONIC GOLDMINE CABLE T.V. CONVERTERS Me Electronic adadr has ore of the greatest selections WHY PAY A HIGH MONTHLY FEE? d 1l5Je electronic kilo available in the Wald We hate over 130 ers and almost 1,000 unique. bargain p' . compo- YOUR I.C. SOURCE nent cove new 1990 CAN /211. Request you mcy today, or better ytt, order and be placed on our Peened Customer mailing list to be the first to receive new catalogs den trey are printed. COLLIMATOR PEN (INFRA -RED) íì MINI GEIGER COUNTER A low power collimator pen containing a KIT * MOVPE grown gain guided GaAlAs laser. Everyone knows how fascinating and useful Geiger Counters are, but their This collimator pen delivers a maximum price is usually $100 or morel We've made a tremendous CW output power of price 2.5 mW at 25°. breakthrough) Not only is our Geiger Counter Kit C6430 These collimated laser sources are one of the smallest, it's the most reasonable designed for industrial applications $59.95 priced Geiger Counter available anywhere All such as data retrieval, telemetry, Jerrold, Oak, Hamlin, Zenith, Scientific This ultra-sensitive kit detects Alpha, alignment, etc. Atlanta, Magnavox and all specialized cable Beta, Gamma and X-ray radia- The non -hermetic stainless equipment available for shipment within 24 steel encapsulation of the pen tion and emits dicks in pro- is specifically designed for portion to the intensity ® hours. 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No Illinois Orders Accepted. QUALITY COMPONENTS...LOW PRICES SINCE 1983 20W + 20W STEREO AMP KIT Inv separ0e high power apps on one PC board ban amp has its own level 329101236 ELECTRONIC camera repair: Five day puts out an incredible residency 18 LASER DIODE 20 Walls RMS. Features :_._.110111131 and home study lessons. Video aided and 800 - red 1E0 -on" 101600r o p. O -"- number supported. Free brochure. C & C ASSOCI- (INFRA -RED) are low dsbdlon Q O, ck- ATES, 300 Highfall, Greencastle, IN 46135. (317) Designed for general industrial cuilry. Great stereo -,: Inosteranpbryauar 653-3405. Regulated by Commission on Proprie- low power applications such as .Q reading optical discs, optical sound system. use web ® tary Education. any of fQ -r memories, barcode scanners, se- y rs Iapaasblo 20 h _..'. curity r BECOME a TV satellite news technician. Home systems, alignment, etc. woos. operates on The guided training. Free info. SPACELINK, PO Box 8497, gain laser is con- 12VDC. See d board: 6" x 225" Complete with all pans. PC Inane and wstrucuora structed on an n -type gallium C6442 $19.95 Bridgeport, CT 06606. arsenide substrate with a Metal Or- ELECTRONIC review ganic Vapor Phase Epitaxial proc- MINIMUM ORDER: $10.00 plus $3.00 shipping and handling. Detailed electronics review- ess (MOVPE).. We accept MC, Visa iml.Money Orders. ing for bettering grades, interviews, and promotions. The device is mounted in a SEND ORDERS TO: The Electronic Goldmine Over 300 pages $39.95 include $4.25 shipping. hermetic SOT148D encapsula- P.O. Box 5408 Scottsdale, AZ 85261 USER -GRAPHICS, Education Department, 7136 tion. (diameter 9.0 mm) PHONE ORDERS: 16021 451-7454 Everett, Boise, ID 83704-7415. The S81053 is standard equipped with a monitor diode, iso- CIRCLE 177 ON FREE INFORMATION CARD lated from the case and optically coupled to the rear -emitting fascet of 000 the laser.This fast -responding moni- TEST EQUIPMENT tor diode can be used as a sensor to ACCESSORIES control the laser optical output level. BE a recording engineer; Train at home for high- paying - Exciting careers. Free information. AU- LOW cost oscilloscope probes, multimeter test LIST PRICE: $38.80 OUR PRICE: DIO INSTITUTE, 2174 $9.99 Union St. Suite 22K, San leads. Save over 50%. 1 (800) 772-1519 free cata- Francisco, CA 94123 log. PROBEMASTER INC., WE CARRY A FULL LINE OF COMPONENTS! 4898 Ronson Court, BASIC video cleaning and maintenance. TV one San Diego, CA 92111-5000. half hour, VCR one hour. $38.00 each. JAMES BRADFORD, PO Box 38359, Detroit, MI 48238. EPROMS P.O. 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Also PISS SHOW YOU WHERE TO FIND UNIQUE, 27C16 24 2048x8 450ns 25v -CMOs) 3.% 3.79 3.41 address list of government 2732 24 40%x8 45ons 25v) 3.79 380 3.24 100+ agencies, univer- UNUSUAL ANO HARD-TO -FIND ITEMS. 2732A-2 24 40%x8 200ns 2101) 3.79 3.60 3.24 sities, US, foreign shipping companies, all potential S rI.-.11 2732A 24 40%x8 2509 210 3.69 3.51 3.16 Orders 800-783-4624 employers.SendL$7.50337 to KNOWLTECH INC., POB 27324-4 24 40%x8 21v 3.19 3.03 2.73 1MS2532 24 4096.8 <5Ons 25v 5.79 550 4.95 1070, St. Pet, A Notional PubIk thin For The Reyin1And Selling Of 9sehenk Equip ont TM52532 24 40%x8 450ns 25v 1.99 189 1.70 27032 24 4096.8 450ns 250-CMOSI 4.19 3.% 3.58 2764.20 29 819258 2009 21v) 399 3.79 341 COMPLETE digital training course. Comprehen- 2764 28 8192.8 3.79 360 3.24 sive overview of digital electronics. Super handy 2764A-20 28 8192.8 2200ns(12.h 3.99 3.79 3.41 27648 28 619288 250ns (125v/ 3.29 3.13 2.82 desktop reference! Hundreds of pages/illustrations. 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LAWN MOWER and ground the R73 -R72 junction. sistors.) Transistor IC14-a provides an That causes QI to turn on and + 30 amplified output at its collector with continued from page 74 volts to be applied to the power the help of pull-up resistor R97 -a. MOSFET inputs (J22 pin 25). When The output is coupled to inverter (minimum speed) to +8.0 volts the forward output signal drops to O IC14-a for buffering and signal inver- (maximum speed). Pin 4 will have an volts, Q2 will turn off and Q3 will be sion. The TTL output of IC14-a (pin active PWM output and pin 7 will turned on. That causes the voltage at 2) is sent to the CPU board through remain at -10 volts. Conversely, J22 pin 25 to quickly return to O volts. J22 pin 2 for processing. when the left wheel moves in reverse, The resultant output is an amplified the input voltage will vary between PWM signal that varies between 0 and Motherboard -0.7 volts (minimum speed) to + 30 volts. The process is identical The motherboard provides the in- - 8.0 volts (maximum speed), and for the outputs at pin 7 of IC9 and pins terconnections between the CPU the voltage at pin 4 will remain at -10 4 and 7ofIC10. board, the motor -controller board, volts. Therefore, each drive wheel can and the power board. The mother- be made to move in the forward or Sensor amplifiers board is a simple two-sided PC board reverse direction by simply changing There are 15 identical grass -sensor that contains three edge connectors. the polarity of the input signal at pins amplifiers contained on the motor - The schematic diagram of the mother- 9 and 11. controller board (see Fig. 4). The out- board will be shown next month. puts are identified as BD1-BD15. Driver transistors Since all the amplifier circuits are Next month Transistors QI -Q12 are used as identical, we will describe only the Unfortunately, you'll have to wait drivers at the output of the PWM IC's operation of the BD1 amplifier. until next month for details on how to (IC9 and IC10). Those transistors are The input to the amplifier is AC build the motor-controller board and required to convert the ± 10 -volt drive coupled by capacitor C27. SIP-re- also the motherboard. We'll also pro- signal from the UC3637's into a 0- to sistors R95 and R96 provide tran- vide foil patterns for the main and + 30 -volt drive signal required by the sistor-array IC16's bias voltage. (In motor-controller board if you wish to power MOSFET's (contained on order to conserve as much space as etch pour own PC boards. We will power board) to turn the drive wheels. possible, transistor arrays IC16 and show you how to assemble all of the As the forward output signal (IC9 pin IC17 were used for most of the ampli- mechanical components and wind up 4) rises to + 10 volts, Q2 will turn on fier circuits instead of discrete tran- with the completed working unit. R -E

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ELECTRONICS QUALITY PRODUCTS COMPETITIVE PRICING PROMPT DELIVERY Intel Math Coprocessors PROTOTYPING PRODUCTS Jameco Solderless Breadboards Prototype 8088 or 8086 Systems Design Stations 8087 5MHz $89.95 WM2 8087-2 8MHz $129.95 JE24 3087-1 10MHz $169.95 WM1 & WM2 Features: Removable solderless breadboard Variable and fixed DC JE27 power supply Multi -frequency sig- 80286 Systems nal generator Analog multimeter 8 bicolor LEDs (red & 80287 6MHz $139.95 green) 8 logic switches Logic probe Lighted power 80287-8 8MHz $209.95 switch Fuse overload protected Sturdy ruggedized 80287-10 10MHz $239.95 JE21 JE23 case 80386 Systems Part Dim. Contact Binding WM1 Special Features: 4 potentiometers Built-in speaker No. L" x W" Points Posts Price 80387-16 16MHz $349.95 WM2 Special Features: Pulse Generator Binary coded 80387-20 20M Hz $399.95 400 0 JE21 3.25 x 2.125 $4.95 decimal (BCD) to 7 -segment decoder/driver DB25 connector 80387-25 JE23 x 830 0 25M Hz $499.95 6.5 2.125 $6.95 Frequency counter (1 Hz to 1 MHz) 80387-33 33MHz $649.95 JE24 6.5 x 3.125 1,360 2 $12.95 JE25 6.5 x 4.25 1,660 3 $17.95 WM1 Analog Prototype Station $199.95 JE26 2,390 4 $22.95 aam ;..s"pteeem 6.875 x 5.75 WM2 Digital Prototype Station $249.95 JE27 3,220 4 SIP Modules 7.25 x 7.5 $32.95 41256A9A-80 80ns,256Kx9 $54.95 A.R.T. EPROM Programmer UVP EPROM Eraser 41256A9A-10 100ns,256Kx9 $44.95 Oscilloscope Probes

421000A9A-70 70ns, 1 Megx9 $169.95 Attenuation: xt / x10 Capacitance 421000A9A-80 8Ons, 1 Megx9 $124.95 (LF180):180pF 421000A9A-10 100ns, 1 Megx9 $116.95 / 22pF; (LF210): 94000L-80 8Ons, 4 Megx9 $499.95 40pF / 17pF 94000L-10 100ns.4 Megx9 $499.95 LF180 40MHz Oscilloscope Programs all current EPROMs in the 2716 to Erases all EPROM's Erases 1 chip in 15 Probe SIMM Modules $19.95 27512 range plus the X2864 EEP ROM Min. and 8 chips in 21 min. UV intensity: 41256A9B-80 80ns,256Kx9 $49.95 LF210 100MHz Oscilloscope RS232 port Software included 6800 UW/CM2 41256A9B-10 Probe $29.95 100ns, 256Kx9 $39.95 EPP $179.95 DE4 $69.95 421000A8B-10 100ns, 1 MegxB $109.95 ememeemeeamemezem 421000A9B-70 7Ons, 1 Megx9 $169.95 GoldStar 20MHz IMMIMIUMMUMMMIC 421000A9B-80 8Ons, 1 Megx9 $119.95 Oscilloscope and 1GHz Frequency Counter 421000A9B-10 100ns, 1 Megx9 $113.95 Soldering and Desoldering Stations 94000S-80 BOns,4 Megx9 $499.95 60 Watt Analog Display Soldering Station Electronic temperature 94000S-10 100ns.4 Megx9 $499.95 control from 200° to 878°F Cartridge heating element for a longer GS7020 life of the soldering tip XY1683 $59.95 NEC V20 & V30 Chips 60 Watt Analog Display Soldering Station Electronic temperature UPD70108.5 5MHz, V20 Chip $5.25 Large 6" rectangular display control from 200° to 878°F Ceramic heating element for a steady temperature and long life UPD70108.8 8MHz, V20 Chip $6.95 High sensitivity: 1 mV/div UPD70108.10 10MHz, V20 Chip $10.95 GS7020 oscgloscope $399.95 XY2660 $89.95 UPD70116.8 8MHz, V30 Chip $7.95 Wide measuring range 60 Watt Digital Display Soldering Station Electronic temperature UPD70116.10 10MHz, V30 Chip $13.49 Measured value hold function control from 200° to 878°F Temperature displayed on easy to read .560"H FC7102 Frequency Counter $299.95 3 -digit LED readout Nichrome heating element Dynamic RAMs XY960 $99.95 TMS4416-12 120ns, 16Kx4 $2.75 Metex Digital 30 Watt Electronic Temperature Controlled Desoldering Station Electronic temperature control from 212° TMS4416-15 150ns.16Kx4 $2.49 Multimeters to 842°F Self-contained 4116-12 120ns,16Kx1 $1.49 high rotary vacuum pump General Specs: 4116-15 XY999 150ns,16Kx1 $1.09 Handheld. high XY999 $279.95 4116-20 200ns,16Kx1 $89 accuracy AC/DC 4164-100 100ns, voltage, AC/DC áY1y.+ïYN9'a13Ë&.e>x,C&.c3``.e.. ß?a°.:`.. 64Kx1 $2.75 a'i. .?:.... ` `x . 3:.a,:...i;ºñ..:$.>V ' '': . current, resistance. s. 4164-120 120ns,64Kx1 $2.39 diodes, continuity, 4164-150 15Dns,64Kx1 $2.15 transistor hFE 51 -Piece Electronic Tool Kit 4164-200 200ns, 64Kx1 $1.75 Manual ranging w/ 41256-60 60ns,256Kx1 $5.25 overload protection The MS305 provides the tools needed for building, 41256-80 8Ons,256Kx1 $3.75 M3650, 3650e & M4650 only: Also measure frequency and capacitance 41256-100 100ns, 256Kx1 $3.15 repairing and general maintenance of most electronic M4650 only: Data hold switch 4.5 digit 41256-120 120ns,256Kx1 $2.95 equipment. A convenient and durable carry -along 41256-150 150ns, 256Kx1 $2.59 combination lock case safely protects M3610 3.5 Dgn Multimeter $49.95 and secures 41464-80 80ns,64Kx4 $5.95 M3650 3.5 Digit Multimeter w/Frequency & this 51 -piece tool kit. From the digital multimeter to 41464-10 100ns, 64Kx4 $4.95 Capacitance $69.95 41464-12 120ns, 64Kx4 $3.95 the desoldering pump this kit is the perfect Item for M3650B Same as M3650 w/Bargraph $74.95 41464-15 150ns.646x4 $3.59 technicians and M4650 4.5 Digit w/Frequency, Capacitance and electronic enthusiasts. 511000P-70 70ns,1 Megz1 $13.95 Data Hold Switch $99.95 511000P-80 8Ons, 1 Megx1 $12.95

511000P-10 100ns, 1 Megx1 $12.35 Tools Included in Multimeter Specials Kit 514256P-80 80ns,256Kx4 $13.45 10' measuring tape Stainless steel scissors 5.25" needle M80: nose pliers 514256P-10 100ns.2566x4 $12.95 Electric tape AC/DC voltage, AC/DC current, resistance, Utility components box 6 piece precision 6" long tweezers 8 diodes, continuity & frequency Full auto - pcs. hex key wrench screwdriver set ranging on DC voltage High/low semi- 7" brush and scraper Digital Multimeter Brush Static RAMs autoranging for AC/DC current and ohms 7" fine point probe Round needle file 10 piece screwdriver set: Data hold switch Extra -large display 7" slotted probe Flat needle file 5 Slotted & 5 Phillips 6116P-3 15Ons,16K (CMOS) $2.79 M80 3.75 Digit Multimeter $59.95 Rosin core solder 6" adjustable wrench Flat nose pliers 6264LP-10 100ns, (CMOS) 64K $6.95 M3900: 30 watt soldering iron Utility knife with extra blade Carrying case: 6264LP-15 150ns, 64K (CMOS) $4.95 AC/DC voltage, AC/DC current, resistance, Desoldering pump Bent needle nose pliers 17.63"W x 12.5"D x 3.5"H 43256-10L 100ns, 256K $10.95 diodes, continuity, dwell angle and engine Soldering stand Diagonal cutting pliers 43256-15L 15Ons,2561< $9.95 RPM High surge voltage protection 62256LP-15 150ns, 256K (CMOS) $10.95 M3900 3.5 Digit Multimeter $59.95 MS305 $119.95 Partial Listing Over 4000 Components and Accessories in Stock! Call for Quantity Discounts 90 CIRCLE 114 ON FREE INFORMATION CARD

www.americanradiohistory.com Mail Order Electronics Worldwide Request Jameco's 1990 Catalog for a Complete arreco Listing of Components, Test/Measurement Equipment ELECTRONICS and Computer Products

Jameco 20MHz 80386 Desktop Computer Kitt Jameco Floppy Digitizer Tablet Disk Drives Fully IBM Compatible Free! Concurrent 386 (Disk Operating System) Mitsubishi Software Included MF353B 3.5' 720KB Internal Drive $99.95 Free! QAPLUS Diagnostic Software Included! Toshiba Free! WORDSTAR EASY Word Processing 356KU 3.5' 1.44MB Internal Drive .. $109.95 Software Included! Teac FD55B 5.25" 360KB Half Ht. $89.95 1MB RAM Included, Expandable to 8MB onboard, AutoCAD 10 template and four - FD55G 5.25' 1.2MB Half Ht. $99.95 16MB with optional expansion board button puck Resolution: up to '. 8/16/20MHz Keyboard Switchable Operation 1016 lines per inch Accuracy: AMI BIOS ROMs Included ±.025" Emulates three of the MiniScribe Fliptop Case w/200 Watt Power Supply worlds most popular formats: Hard Summagraphics MM, Summa - MiniScribe 3.5" 40MB RLL Hard Disk Drive graphics Bit Pad One, Calcomp Drives Teac 1.2MB Floppy DSHD Disk Drive Shown with VGA Option (not included) 2000 EEPROM allows custom Fujitsu 101 -Key (Enhanced) Keyboard JE2059 Multiscan Monitor and VGA configuration Card....$669.90 (See Blow) MFM JCAD Digitizer Tablet $199.95 M8425 20MB (68ms) 3.51HH $224.95 Stylus Two Button Stylus .... $39.95 M8425XT 20MB (68ms) 3.5'HH (K4) $269.95 JE3550 20MHz 80386 Compatible Kit $1599.95 1' M8425AT 20MB (68ms) 3.5'HH (Kit) $339.95 Logitech ScanMan Plus RLL Jameco IBM Scanner M8438 30MB (68ms) 3.51HH $249.95 M8438XT 30MB (68ms) 3.5"HH (Kit) $299.95 IBM PC/XT/AT PC/XT/AT M8438AT 30MB (68ms) 3.5'HH (Kit) $389.95 Compatible Compatible 4" Scanning M8450 40MB (46ms) 3.5'HH $329.95 Cards Window M8450XT 40MB (46ms) 3.5"1-81(Kit) $369.95 400 dpi M8450AT 40MB (46ms) 3.5'HH (Kit) $429.95

SCANP ...... $219.95 (Kit) includes Hard Disk Drive, Controller Si Cables

Logitech Colorado Mice JE1 043 360KB/720KB/1.2MB/1.44MB Floppy Disk Controller Card (PC/XT/AT).. $49.95 Memory JE1 050 Monochrome Graphics Card w/Parallel Printer Port (PC/XT/AT) $49.95 Systems JE1 052 Color Graphics Card w/ Parallel Printer Port (PC/XT/AT) $49.95 MSER Serial Mouse & MouseWare 40MB Tape Software $89.95 JE1 055 EGA Card w/ 256K Video RAM (PC/XT/AT) $139.95 Back -Up MBUS Mouse w/Bus Board & Mouse - VGA w/256K Video RAM (PC/XT/AT) $199.95 JE1057 8/16 -Bit Card Ware Software $99.95 IBM PC/XT/AT/386 Compatible Back-up 40MB in 40 minutes Back-up 60 to 120MB JE1060 I/O Card w/ Serial, Game, Printer Port & Real Time Clock (PC/XT) ... $59.95 MPS2 PS/2 Mouse & MouseWare with extended tapes and data compression JE1062 RS232 Serial Half Card (PC/XT/AT) $29.95 Software $79.95 software Includes 40MB tape cartridge <"lj::::Czw:"'S.\à`À< JE1065 I/O Card w/ Serial, Game and Parallel Printer Port (AT) $59.95 DJ 10 40MB Tape Back -Up $299.95 JE1077 Multi I/O Card w/ 360KB/720KB/1.2MB/1.44MB Floppy Controller (AT) $99.95 Modems KE10 External Enclosure Kit $149.95 TB40 40MB Tape Cartridge $24.95 9600E 60MB Tape Cartridge Pictured TB60 $32.95 EGA, VGA & Multiscan Monitor Packages Relisys 14" EGA monitor and EGA card package O External Modems Mau Order Electronics Worldwide (720 x 350 max. resolution) 1200C Datatronics 1200 Baud $89.95 JE1059 EGA Monitor & EGA Card $459.95 2400C Datatronics 2400 Baud $149.95 9600E Prometheus 9600 Baud $699.95 arreco Relisys 14" Multiscan monitor and 16 -Bit VGA card ELECTRONICS Internal Modems package (800 x 600 max. resolution) 1200B Jameco 1200 Baud $49.95 1355 Shoreway Road, Belmont, CA 94002 JE2059 Multiscan Monitor & VGA Card $669.90 2400B Jameco 2400 Baud $99.95 24 Hour Order Hotline meneemmuntweeenatee , , .,, .) (415) 592-8097 Relisys 14" VGA monitor and 16 -Bit VGA card package IBM $50.00 Minimum Order (720 x 480 max. resolution) Compatible FAX's (415) 592-2503 or (415) 595-2664 JE2061 VGA Monitor & VGA Card $599.90 JE2061 Cases and Telex 176043 - Ans. Back: Jameco Blmt .: ...: Power Data Sheets - 506 each ;.: ; m?imeeee>:'.':à`,.àï:.e` \ÿi:;1?::i`:';,``'`c?t,:,>.. ..::asës<,::ä?,3si:;« Supplies For a FREE 48 -Page Flier send $2.00 to cover First Class Postage and Handling IBM PC/XT/AT MEI 100 -Key © 1990 Jameco Electronics 7/90 CA Residents Add Compatible Keyboards Microtype Keyboard 6.25%, 6.75% or 7.25% Sales Tax Shipping - Add 5% plus $1.50 Insurance (May vary according to weight and shipping method) Terms: Prices subject to change without notice. JE1030 JE2012 Items subjec to availability and prior sale. Complete list of erms/warranties is ava table upon rogues JE1010 Flb-Tap Standard PC/XT Case $39.95 IBM is a ragiste ed trademark of International Business Machin JE1011 see Standard PCJxT Case $39.95 Please JE1030 150 watt PC/XT Power Supply $59.95 FKB4700 IBM PC/XT/AT/386 Compatible JE1032 200 wan Baby AT Power Supply $89.95 refer to an amazing 60% of the desk Saves JE1035 300wattAT Poser suppy $139.95 Mall Key 2 JE2015 84 -Key Standard AT Style space used by equivalent standard C JE2011 vertical Case w300W Par. Supply $249.95 when Layout $59.95 keyboards MasterCard. JE2012 Mrweor Case wl200W Per. Supply $149.95 FKB4700 101 -Key Enhanced Layout I ordering with 12 Function Keys $69.95 MIRU $129.95 JE2019 F -Top Bale AT Case $69.95 cR O Customer Service Technical Assistance Credit Department All Other Inquiries (415) 592-8097 7AM - 5PM P.S.T. CIRCLE 114 ON FREE INFORMATION CARD 91

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P.O. Box 567 Van Nuys, CA 91408 ...... THUMBWHEE..'.SWITCH, RG 11/U 75 OHM INSTRIIMENT ; UND ACTIVATED VIDEO CABLE ENCLOSURES 1 pole 10 position SWITCH decimal encoded 100 ft. or High quality molded ABS switches which 200 ft. rolls of Instrument enclosures. interlock to make RG 11/U Integrated PC board up desired number terminated to standoffs and two sets or digits. Terminates to 11 pc pins (1 corn - heavy duty F of vertical mounting slots for mon and 10 poles). Each section measures connectors. front and rear sub panels. All enclosures are .31' wide X .20' high X .78 deep. End plates Includes Ile A 11 6' wide X 6 1/4' deep. Choice of three heights. PC board with electret can be added to forma .94' high bezel. 75 ohm terminator and F-61 splicer on one Includes non-skid rubber feet and hardware. mike responds Available to sounds in immediate vicinity. CATI SWTH-9 $1.25 each end. New cables manufactured for IBM PC In beige, Ivory, blade, and blue. Originally Penal ht CATI part of sound activated light organ. Shuts 10 for $10.00 networks. IBM P/N 1501908 COM/SCOPE. 2 WV CATI M B -A $7.50 each 10 for $65.00 off when sound is not present. Includes CATI RG -11-1 100 ft. roll $15.00 2 Sil' CATI 1413-B $7.75 each 10 for $67.50 END PLATES - CATI SW-9EC hook-up diagram per CATI RG -11-2 200 ft. roll $27.50 3' CATI MB -C $8.00 each 10 for $70.00 $1.00 set Please specify color. CATI SAB-2 $2.50 each

SWITCHES NICKEL-CAD > : B HOUR AUTO LED'S L.E.D. FLASHER KIT ITT PUSH BUTTON BATTERIES HUTOFF TIMER (RECHARGEABLE) STANDARD JUMBO Two LE.D's flash in fTT MDPL series. 3r4' X M.H. Rhodes, Inc.Mark-Time/90007 DIFFUSED II -34 are unison when a 9 volt 1/2 grey rectangular key Timer fits standard battery in attached. cap. S.P.S.T. N.O. Push 3' deep wallbox. Rated RED CATI LED -1 This kit includes a to close. RATED: 0.1 amp switching. 10ór$1.50 100 for $13.00 20 amps 125 Vac. p.c. board, all the parts . @ Turn 0.25 amp carry current P.C. mount. knob to desired time. GREEN CATI LED -2 and instructions to make a simple flasher CATI P&8 650 each 10 for AAA SIZE $1.50 each $6.00 Includes hardware, beige 10 ta $2.00 t00 for $17.00 circuit. A quick and easy protect for any- 100 for 1.2 volts 180 mAh $50.00 wallplate, one with basic soldering skills. CATI NCB -AAA and knob. UL YELLOW CATI LED -3 ' CATI LEDKIT S1 75 per kit SPDT PUSHBUTTON and CSA listed. CATI TMC-6 10ór$2.00 100 for $17.00 AA SIZE Marquardtl 1843 $2.00 each $5.75 each 10 for $50.00 a= 1.25 volts Rated 6 amps O 125250 Vac. qy 500 mAh FLASHING LED LED CHASER KIT Black plastic pushbutton. CATI NCB -AA SPECIAL PURCHASE with butt in Bashing circuit Build this variable Switch body: .92' x .9e x .6s. AA SIZE $2.20 each operates on 5 volts... speed led chaser. CATI PB -18 $1.65 ea. 10 for $15.00 WITH SOLDER TABS 210 MED 330 V RED $1.00 each 10 lads flash CATI NCB -SAA PHOTOFLASH CAPACITOR CAT! LED-4 10 for $9.50 PUSHBUTTON SWITCH sequentially at GCf homsenl 35-420 C SIZE $4.25 each Rubicon CE photoflash capacitor. GREEN $1.00 each whatever speed S. P.S.T. normalcy open momentary 1.2 volts 1200 mAh 0.79' dia. X 1.1- high. These are CATI LED-40 10 la $9.50 you set them for. CATI NCB -C pushbutton switch. Red plastic new capacitors that have been Easy to build kit includes pc board, parts actuator 0.57 diameter. Chrome D SIZE $1.50 each prepped with 1.4' black and red BI -POLAR LED and instructions. Ideal for special lighting wire Light. RED one drecson, bezel 0.68 diameter. Threaded bushing 1.2 volts 1200 mAh leads soldered to the terminals. effects, costumes, etc. Operates on 3 to GREEN ehe other. Two leads. mounts in .50' diameter hole. Rated CATS NCB -D CATS PPC-210 $2.50 each 9 volts. PC board is 5' X 2.25'. A great CATI LED -6 2 for $1.70 3 amp O 250Vec. Solder loop terminals. 10 for $22.50 100 for $200.00 one hour project. CATI AEC $6.50 ea. CAT* PB -20 $1.00 each ::XENON:TUBE Large quantities available. Call for pricing. LED HOLDER ,. fF 1 Two piece holder. STEPPING MOTOR WALL TRANSFORMERS 22/44 PIN CONNECTOFi :<: a CATI HLED 10 for 65e 8 1' long flashtube with 3 red ALL PLUG 12' CONTROLLER KIT and dadi leads. Ideal fa elec- DIRECTLY Pmmmnhmli111m LED GRAB BAG tronic Bash or strobe projects. Learn about INTO 50 assorted 120 VAC .156' pin spacing, 0.200' between double stepping OUTLET CAT/ FLT -3 2 fer $1 00 L E.D.'e rows, gold contacts, P.C. mourning. motors while 12 Vdc O 500 ma. CAT! DCTX-125 $4.50 Many different RELAYS SPECIAL Same as AMP! 2-530655-6. shapes, colors, razes 9 Vdc ®1 amp CAT! DCXT-0S1 $6 00 Round, building this CAT! EBC-1G 51 00 each 10 for $8 00 rectangular, curved, etc. 24 Vac @ 625 me. CATI ACTX-2462 $3 25 5-6 VDC SIP simple circuit. CAT/ GRLF.D Includes circuit board and all parts ELECTRONIC GAME BOARD $4 00 per assortment SERVO MOTOR .1 Electrrd'BBlue Boy/ except 12 Vdc power supply. BBStA05A10 CATS SMKIT $18.00 each 3 Vdc servo with potentiometer. 5-6 Vdc, 500 ohm coll. OPTO SENsOR . Ideal for robotics a remote S.P.S.T. normally open reed control model erperinantation. rh"Ilpl relay. 0.5 amp contacts. SIP con- U shaped package Rotates approx. 140 degrees. figuration. 1' X .375' X .3'. with mounting ears. RECHARGEABLE Pot connected to motor varies CAT/ RRLY-SIPS 1/r opening. BATTERY PACK (USED) from 500 to 3000 ohms. $1.10 each 10 for 51o.00 The inner workings of an electronic Scrabble 3/4' mounting ears. 1.53' X 0.95 X 1.65'. 0.67' diameter rubber game. Operates on 6 Vdc. 8 digit alpha- Four AA nickel cad- 5 VDC LATCHING RELAY CATI OSU-6 wheel attached to motor shaft can be used numeric readout, 45 button keypad, 14 transis- mium batteries con- Aromate RSI2D-5V 500 each as a capstan a can be easily removed. Miriatue tors, 2 I.C.'s, 1 plezo element and other good- nected in series to SPDT, 10 for 54.50 100 for $40.00 Prepped with capacitors, chokes and wire dual col latching ies. Top and bottom row of keypad buttons make a 4.8 volt pack. leads. CATO SVO-2 2 fa Sr 00 are function keys, middle 3 relay. 5 Vdc, rows are alphabet- :>:BTEPPER Batteries are in a 1 ic. No Instructions available. X ' 170 ohm cats amp. TTL com- 6 4.45. MOTOR 2 X 2 configuration 7.rIU99::PHOTO:TRANs($TQ. patible. UL and CSA recognized. CATS STS $1.75 each 10 for $15.00 Airpax P/N C82711 -M1 with a 2 pin connecta 0.767' X 0.394' X 0.394' TO -18 case with window. For 17 Vdc attached. The four CATS LRLY-6DC $2.50 each ::7itEPHQkE:EtiUP.WNß

Infrared emitting photo diode. moult with pia on DIP spacing. inductance: 300 mH min., at 1kHz, 1 volt. CATS SMT-6 $6.00 each $3.00 per pack 10 packs for $25.00 CATITIL-31B $1.00 ee. 10 for $9.50 CATI RLY-787 $1.50 each CATO TCTX-1 $1.25 ea 10 for 511.00 10 for $50.00 CATS NCB-41AAU ORDER TOLL FREE 1-800-826-5432 r-e-WI6-hO9,oc aTa0 CALL OR WRITE FOR OUR INFO: (818)904-0524 MAIL DISCOVER ORDERS TO: FAX: (818)781-2653 MINIMUM ORDER $10.00 FREE QUANTITIES LIMITED 60 PAGE CATALOG ALL ELECTRONICS CALIF. ADD SALES TAX MUM USA: $3.50 SHIPPING WITH OVER 4000 PARTS! P.O. BOX 567 FOREIGN ORDERS OUTSIDE THE U.S.A. PLEASE SEND VAN NUYS, CA 91408 INCLUDE SUFFICIENT Keel $2.00 POSTAGE FOR A CATALOG SHIPPING. NO C.O.D.

92 CIRCLE 107 ON FREE INFORMATION CARD www.americanradiohistory.com M MICROCOMPUTER MARKETING COUNCIL JDR Microdevuces IIM II 30 DAY MONEY BACH GUARANTEE 1 YEAR WARRANTY ON ALL PRODUCTS TOLL -FREE TECHNICAL SUPPORT

JDR caters to the developer oit with a full line of prototyping BUILD YOUR OWN 286 SYSTEM FOR UNDER $650 virofeLD &" programming products. Request A WAY TO SAVE! our catalog for the complete line! ITS A GPEAT WAY TO LEARN AND GREAT HERE'S UST ONE OF OUR MOST POPULAR CONFIGURATIONS:

MODULAR PROGRAMMING SYSTEM MCT-M2B6-12 8/12MHZ MINI 286 MOTHERBOARD $199.95 MODULES USE A COMMON HOST ADAPTOR CARD -- MCT-MGP MONOCHROME GRAPHICS ADAPT $49.95 1 SLOT PROGRAMS EPROMS, PROMS, PALS, MORE! MCT-FDC-HD 360K-1.44MB FLOPPY CONTROLLER $49.95 HOST ADAPTOR CARD $29.95 CASE -JR MINI FLIP -TOP CASE W/150W P.S. $149.95 UNIVERSAL INTERFACE FOR ALL FDD-360 360K 5-1/4" FLOPPY DISK DRIVE $69.95 PROGRAMMING MODULES, JDR-MONO MONOCHROME MONITOR (GREEN) $69.95 SELECTABLE ADDRESSES BIC -506G STANDARD 84-KEY KEYBOARD $59.95 PREVENTS CONFLICTS MOLDED CABLE TOTAL S (STEM (OK INSTALLED) $649.65 MOD -MAC OPTIONAL COMPONENTS UNIVERSAL MODULE $499.95 MOTHERBOARDS PALS, -POLAR PROMS, PROGRAMS EPROMS, EEPROMS, BI MCT-TUF BO -10 4.77/I0MHZ SINGLE CHIP 8088 $99.95 8748 8 8751 SERIES DEVICES; 16V8 AND 20V8 GALS (GENERIC MCT-M286-16N 8/16MHZ 286 W/NEAT CHIPSET $289.95 ARRAY LOGIC)FROM LATTICE, NS, SGS TESTS TTL, CMOS, 10/20MHZ 286 CHIPSET $389.95 DYNAMIC & STATIC RAMS LOAD DISK, SAVE DISK, EDIT, MCT-M206-20N W/NEAT BLANK CHECK, PROGRAM, AUTO, READ MASTER, VERIFY AND Llttlefoofr" COMPARE TEXTOOL SOCKET FOR .3" -6"W. IC'S ( 8-40 PINS) MOD-MUP UPRIGHT CASE $249.95 MOD -MPL -SOFT CUPL SOFTWARE $99.95 SPACE SAYING DESIGN HOLDS ALL SIZES OF MOTHERBOARDS AND INCLUDES A r EPROM MODULE 250 WATT POWER SUPPLY $119.95 MOUNTS vOR 3 FLOPPY AND PROGRAMS 24-32 PIN EPROMS, CMOS EPROMS & EEPROMS 4 HARD D 3IVES FROM 16K TO 1024K HEX TO OBJ CONVERTER AUTO, VGA COMPATIBLE PACKAGE «TURBO & RESET SWITCH BLANK CHECK/PROGRAMNERIFY VPP 5, 12.5, 12.75, 13, 21 LED SPEED DISPLAY 25 VOLTS NORMAL, INTELLIGENT, INTERACTIVE & QUICK $499.95 & CASE -100 PULSE PROGRAMMING ALGORITHMS 111 720 X 540 MAX RESOLUTION, CASE-FUP FLIP TOP CASE FOR 8088 MB'S $39.95 MOD -MEP 640 X 480 IN 16 COLORS, 528 X 480 POWER SUPPLIES RESOLUTION IN 256 COLORS OTHER MODULES: PAL PROGRAMMER. DIGITAL TESTER. PS -150 150 WATT SUPPLY FOR 8088'S $59.95 IBM STYLE MONITOR BI -POLAR PROGRAMMER, MICROPROCESSOR PROGRAMMER - FOR $89.95 VGA, EGA, CGA, AND MGA COMPATIBLE FROM $129.95 TO $259.95- CALL FOR INFORMATION PS -200X 200 WATT SUPPLY 8088'S PS -200 200 WATT SUPPLY FOR 286/386'S $89.95 VGA-PKG (INCLUDES VGA CARD AND MONITOR) KEYBOARDS JDR-RGB 14" RGB MONITOR $239.95 JDR-AMBER 12" TTL MONOCHROME AMBER .. $69.95 EPROM PROGRAMMER $129.95 BTC-5339 101 KEY ENHANCED KEYBOARD $69.95 MAX -5331 101 KEY W/TACTILE FEEDBACK (286) $69.95 PROGRAMS 27XX AND 27XXX EPROMS UP TO 27512 16-BIT VGA DISPLAY ADAPTOR $199.95 SUPPORTS VARIOUS PROGRAMMING FORMATS & VOLTAGES DRIVE CONTROLLERS SPLIT OR COMBINE -640 X 480 RESOLUTION CONTENTS OF MCT-FDC-H D4 4 -FLOPPY DISK CONTROLLER $59.95 256K VIDEO RAM EXPANDABLE TO 512K SEVERAL EPROMS OF MCT-HDC HARD DISK CONTROLLER $79.95 64 LEVELS OF GREY SCALE DIFFERENT SIZES MCT-AFH 286/386 FLOPPY/HARD CONTROL .. $149.95 MCT-VGA-16 READ, WRITE, COPY, MCT-EGA ENHANCED GRAPHICS ADAPTOR $149.95 BLANK CHECK & VERIFY MEMORY/MULTIFUNCTION CARDS MCT-MGMIO MONOGRAPHICS MULTI I/O $119.95 SOFTWARE FOR HEX MCT-RAM 576K RAM CARD (OK) $49.95 AND INTEL HEX FORMATS MCT-IO MULTI I/O CARD $59.95 MOD -EPROM 2400 BAUD MODEM $89.95 1.44MB FLOPPY DRIVE $99.95 EPROMS /+ 2400/1200/300 BAUD HAYES COMPATIBLE ULTRA HI3H DENSITY AS COM1,2,3 OR 4 27128 16384x8 25085 12.5V 28 4.25 CONFIGURE READ/WRITE 720K DISKS TOO PROCOMM 27128A-200 16384x8 200ns 12.5V 28 5.95 BUILT-IN SPEAKER BLACK OR BEIGE COMMUNICATIONS SOFTWARE PARTIAL LISTINGS ONLY - MANY OTHERS AVAILABLE! FDD-1.44X BLACK FDD-1.44A BEIGE MCT-24 I

FDD-1.2 5-1/4" DS/HD 1 2MB FLOPPY $95.95 MCT-12I 1200 BAUD INTERNAL MODEM $59.95 EPROM ERASERS SEAGATE HARD DRIVES DATARASE II $39.95 DYNAMIC RAMS SHIRT POCKET SIZE! 21.4MB KIT PART# SIZE SPEED PINS PRICE ALL SIZES UP TO 4 AT A TIME $249 4164-150 6553661 150n$ 16 2.49 ERASES MOST EPROMS IN 3 MINUTES KIT 41256.150 26214451 15083 16 2.59 DATARASE II 32.1MB $279 41256-120 26214451 121) s tI, 2.95 41256.100 100es 16 3.18 65MS AVG. ACCESSORY KIT INCLUDES 26214451 PE -140T SPECTRONICS 9 CHIP ERASER WITIMER $139.95 41256-80 28214441 8088 16 3,75 INSTRUCTIONS, XT-COMPATIBLE CONTROLLER AND CABLES. 1 MS -80 04857851 8088 18 12.95 PROTOTYPE CARDS CALL FOR PRICES ON OTHER SEAGATE DRIVES i FR4 EPDXY GLASS LAMINATE WITH GOLD PLATED EDGECARD FINGERS AND SILK SCREENED LEGENDS 35MHZ DUAL TRACE OSCILLOSCOPE JIM'S BARGAIN $49995 HUNTERS CORNER WIDE BAND WIDTH ,A/'I., FOR XT VARIABLE HOLDOFF Jim Wharton JDR-PRI WITH 4-5V AND GROUND PLANE 27.95 1X/10XFROBES JDR-PR2 ABOVE WITH I/O DECODING LAYOUT 29.95 JDR's VP Sales FULL 2 ',EAR WARRANT4 PARTS KIT FOR JDR-PR2 ABOVE 8.95 JDR-PR2-PK MODEL -3500 112 WATT SWITCHING 51995 FOR AT MODEL -2000 POWER SUPPLY JDR-PR10 16 -BIT WITH 1/0 DECODING LAYOUT ....34.95 20MHZ VERSION $389.95 OPEN-FRAN ED POWER JDR-PR1O-PK PARTS KIT FOR JDR-PR10 ABOVE 12.95 SUPPLY MADE BY DELTA EXTENDER CARDS DMM-300 34 RANGES, 20.25%. TEMP & TRANS TEST $79.95 .5@10A, *[email protected], .12V@ 1.5A, -12 @ 200mA SIMPLIFY PROTOTYPING AND TESTING DMM-200 3.5 DIGIT,22 RANGES, ±0.25% ACCURACY $49.95 MEASURES 5 X 8.5 X 1.97"; WEIGHS 2.3 LBS. OMM-100 3.5 DIGIT,14 RANGES, ±0.5% ACCURACY .. $29.95 EXT-8088 8-BIT FOR 8088 MOTHERBOARDS 29.95 EXPIRES 715/90 EXT-80286 16 -BIT FOR 286/386 MOTHERBOARDS 39.95 ALL JDR INSTRUMENTS PRODUCTS WARRANTEED 2 YEARS PS-DPS-110AP rUPGRADE YOUR OLD KEY CODE SYSTEM! REQUEST 12 OUR NEW FLYER TO ORDER TOLL FREE 800-538-5000 C LEARN HOW! CUSTOMER SERVICE TOLL -FREE 800-538-5001 TECHNICAL SUPPORT TOLL -FREE 800-538-5002

Terms. Minimum order 510 00. For sn,pp,ng & handling Include 54.00 foi ground and 55 OC for ar Orders over 1 lb and JDR MICRODEVICES. 2233 BRANHAM LANE, SAN JOSE 95124 foreign orders may require additional shipping charges -please contact the sales department for the amount. CA residents co must include applicable sales tas. Prices subject to change without notice. We are not responsible for typographical errors. LOCAL (408) 559-1200 FAX (408) 559-0250 TELEX 171-110 tfl We reserve the right to limit quanta es and to substitute manufacturer. All merchandise subect to pnor sales. A full copy of Ou, O terms is available upon request. Items pictured may only be representative JDR Microdevices and the JDR Microdevices ALSO ORDER VIA OUR BBS (408) 559-0253 10o re,stered of IBM. AT. PS 2 are trademarks of Inte-national Business Machines. are trademarks JOR Microdewces. 93 CIRCLE 113 ON FREE INFORMATION CARD www.americanradiohistory.com ADVERTISING INDEX _ CABLE TV CONVERTERS RADIO -ELECTRONICS does not & EQUIPMENT assume any responsibility for errors that may appear in the index below.

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108 AMC Sales 15 193 SCO Electronics 68

195 Ace Communications 20 176 Sencore 23

75 Ace Products 13 182 Smith Design 67 107 All Electronics 92 - Star Circuits 24 Amazing Concepts 84, 89 83 Synergetics Maims - 63 ONE 10+ UNIT UNITS 84 Appliance Service 13 184 TECI 71 PANASONIC WIRELESS CONVERTER 85.00... 69.00 67 Banner Technical Books 20 190 Unicorn 86 JERROLD 400 COMBO W/REMOTE (DRX3DIC) 134.00... 95.00 98, 192 Beckman Industrial CV3, CV4 194 U.S. Cable 68 JERROLD 400 OR 450 REMOTE HAND UNIT 24.00... 15.00 109 C&S Sales 19 64 Video -Link 94 JERROLD JRX 3DIC 84.00... 65.00 JERROLD SB ADD ON 74.00... 55.00 70 CEI 60 179 Viejo Publications 15, 85 JERROLD SB ADD ON WITH TRI -BI 95.00... 70.00 OAK M-35 COMBO 79.00... 50.00 - CIE 39 180 WPT Publications 71 OAK MINICODE (N-12) 84.00 59.00 HAMLIN MLD 1200 64.00... 45.00 50 Caig Laboratories 25 SCIENTIFIC ATLANTA SA -3 ADD ON 109.00... 75.00 183 Chenesko Products 13 INTERFERENCE FILTER (CHANNEL 3 OR 6) 24.00... 14.00 - Command Products 70 NEW SCIENTIFIC ATLANTA ADVERTISING SALES OFFICE COMBO 275.00.. 215.00 58 Cook's Institute 20 Gernsback Publications, Inc. PIONEER DESCRAMBLER 250.00 200.00 500-B Bi -County Blvd. TOCOM VIP 200.00.. 175.00 196 D&D Electronics 15 ZENITH FLASHING 175.00.. 150.00 Farmingdale, NY 11735 ZENITH SSAVI 125.00... 90.00 - Damark International 66 1-(516) 293-3000 EAGLE PD -3 95.00... 75.00 President: Larry Steckler 127 Deco Industries 13 Vice President: Cathy Steckler VIDEO -LINK 177 Electronic Goldmine 86 For Advertising ONLY 516-293-3000 Enterprises, Inc. 181 Electronics Book Club 7 Fax 1-516-293-3115 520 GLENBROOK RD., SUITE 202 Larry Steckler 121 Fluke Manufacturing CV2 publisher STAMFORD, CT 06906 Arline Fishman Friendly Videos 16 - advertising director ORDERS: 1-800-622-9022 189 Global Specialties 3 Denise Haven CATALOG & INFO: 203-975-7543 advertising assistant - Grantham College 61 Christina Estrada MONDAY - FRIDAY 10 AM 5:30 PM, E.S.T. - advertising associate IMPORTANT: Have make and model 86 Heathkit 22 Lisa Strassman credit manager # of the equipment used in your area. 186 International Components Corp 87 Subscriber Customer Service 113,170 JDR Microdevices 93 1-800-288-0652 OUTPUT PRICE TOTAL Order Entry for New QTY ITEM CHANNEL EACH PRICE 114 Jameco 90, 91 Subscribers 1-800-999-7139 115 Jensen Tools 13 7:00 AM - 6:00 PM M -F MST

178 Jinco Computers 87 NO CONNECTICUT SALES. It SUBTOT. SALES OFFICES is not the intent of VIDEO -UNK Shipping 191 Joseph Electronics 70 to defraud any pay television $3 / Unit EAST/SOUTHEAST operator and we will not assist COD. King Wholesale 84 Stanley Levitan, Eastern Sales Manager any company or individual in Add 5% Radio -Electronics doing so. 87 MCM Electronics 85 TOTAL 259-23 57th Avenue PLEASE PRINT: 53 MD Electronics 88 Little Neck, NY 11362 1-718-428-6037,1-516-293-3000 O CASHIER'S CHECK D M.O. D C.O.D NAME 93 Mark V. Electronics 89 Fax 1-718-225-8594 ADDRESS - McGraw Hill Book Club 26 CITY/STATE/ZIP MID WEST/Texas/Arkansas/Okla. PHONE 61 Microprocessors Unitd 78 Ralph Bergen, Midwest Sales Manager SIGNATURE Radio -Electronics 117 Mouser 20 WAIVER. Since I, the undersigned, fully 540 Frontage Road-Suite 339 understand that the ownership of a cable decoder Northfield, IL 60093 does not give the owner of the decoder the right to - NRI Schools Il, 17 decode or view premium cable channels without 1-312-446-1444 proper authorization from their local cable company, 185 Optoelectronics 30 Fax 1-312-446-8451 hereby declare under penalty of perjury that all products purchased, at any time, will only be used - Pacific Cable 83, 89 on cable TV systems with proper authorization from PACIFIC COAST/ Mountain States local officials or cable company officers in 56 Parts Express 88 Marvin Green, Pacific Sales Manager accordance with all applicable federal and state Radio -Electronics laws. Federal and various state taws provide for 101 Pomona Electronics 12 substantial criminal and civil penalties for 5430 Van Nuys Blvd. Suite 316 unauthorized use. 188 Print Products International 24 Van Nuys, CA 91401 1-818-986-2001 Dated: Signed: 78 Radio Shack 5 Fax 1-818-986-2009

CIRCLE 64 ON FREE INFORMATION CARD

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Fluke Beckman Industrial Feature Model 77 RMS225 Digits 3-1/2 Digits 4 Digits Resolution 3,200 Counts 10,000 Counts Accuracy 0.3% 0.25% Automatic Reading Hold Touch Hold* Probe Hold Analog Bar Graph 31 Segments 41 Segments Battery Life 2,000 Hrs 500 Hrs 10A Range (Fused) (Unfused) Protective Holster 3 Year Warranty True RMS Auto Max MinTM Relative Mode Self-Resetting Fuse (4OmA Input) Price $159* $149

Mfg. Co., Inc. * 1990 Fluke and Philips Catalog Made in the U.S.A. Touch Hold is a registered trademark of the John Fluke the Your best auto -ranging multimeter for other multimeters we've built over and the money. It doesn't happen by accident. years, it's designed for long lasting use. So, go It takes expertise, painstaking FOP, trouble -free >HOLD IREL MAX MI local dis- R&D, and a solid commit- visit your ment to provide you with '''AM.'.Li: tributor today and check out the new the features you've asked for 6mluniududm at a price you can afford. RMS225 digital When you add it all up, the new Beckman multimeter. Once you compare Industrial RMS225 simply outperforms it to the others, the choice any meter in its class. And like all the will be obvious. Beckman Industrial"' An Affiliate of Emerson Electric Co. Instrumentation Products Division 3883 Ruffin Road, San Diego, CA 92123-1898 (619) 495-3200 FAX (619) 268-0172 TLX 249031 Outside California 1-800-854-2708 Within California 1-800-227-9781

www.americanradiohistory.com 20MHz Frequency Counter Capacitance Meter Logic Probe Transistor kster Continuity Tester LED Thster Diode Check l0A Ammeter Voltmeter Ohmmeter A Fistful Of Functions. With more uses and features than most trigger sensitivity, plus an LED tester. Both other hand-held multimeters, the DM27xL meters feature an enhanced display, including and DM25xL really pack a punch; especially a large, easy -to-read LCD, a full set of function when you've got to troubleshoot or analyze annunciators and a battery -saving Auto a variety of components and circuits. Power Off. Standard functions include capacitance Grab a DM25xL for just $109.95, or a measurement to 20µf, logic probe to 20MHz, DM27xL for just $129.95 (suggested retail transistor tester and resistance ranges to price) at your local Beckman Industrial dis- 2000M2. The DM27xL further adds 20MHz tributor. After using one, you won't be able to frequency counting capability with selectable function without it. Beckman Industrial ru An Affiliate of Emerson Electric Co. Instrumentation Products Division 3883 Ruffin Road, San Diego, CA 92123-1898 (619) 495-3200 FAX (619) 268-0172 TLX 249031 Outside California 1-800-854-2708 Within California 1-800-227-9781