48SX Scientific Calculator

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ICD 08559 MAY 1990 82.50 CANACA 13.50

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Special Focus On Math - Solving Products: MathCAD v2.5, Derive v1.60 & CPMCALC4 Math PC Software Hewlett-Packard's New HP 48SX Scientific Calculator Also Featured: A Programmer for the 68701 Microcomputer Chip Electronic Control for Slide Projectors Interfacing 555 Timers To the Reel World

E'ectronic 2.ontro lerler Slide Projector, ip. 36)

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5OO@aht. YCN ELI Eg SE o s tAE R -2000 iì$ß pertornnance The R -2000 is an all band, all mode receivers. receiver with 10 memory channels and Scan the entire frequency many deluxe features such as program- range from 100 kHz to 905 mable scanning, dual 24 -hour clocks MHz with Kenwood's with timer, all -mode squelch and R -5000. R -2000 and noise blankers, a large, f ront- RZ -1. Listen in on mounted speaker, 110 volt AC or foreign music, news. 12 volt DC operation (with the DCK -1 cable kit), and 118 -174 and commentary. (t, Monitor local police. MHz VHF capability with fire, and other public VC -10 option. safety services, as well as the Optional Accessories Marine channels, and the many other R -2000: services 50 MHz and above. super easy! Other useful features VC -10 VHF converter DCK -1 DC TneVH1- convener options InusiDe used IIItneH -5000 include programmable scanning, large, cable kit for 12 volt DC use. and R 2000 built -in speaker, 110 volt AC or 12 volt DC R -5000: R -5000 operation (with optional DCK -2 cable), VC -20 VHF converter VS -1 Voice module DCK -2 for 12 volt DC operation The R -5000 is a high performance, top - VHF capability (108 -174 MHz) with the -1 AM filter SSB of- the -line receiver, with 100 memory VC -20 option, dual 24 -hour clocks with YK -88A YK -88SN filter channels, and direct keyboard or main timer, and even voice frequency readout filter YK -88C CW MB -430 Mounting bracket. dial tuning -makes station selection with the VS -1 option. Other Accessories: SP -430 External speaker SP -41 -1 easier. One hundred memory channels RZ with message and band marker, direct Compact mobile speaker SP -50B Wide -band scanning receiver keyboard or VFO frequency entry, and Mobile speaker HS -5 Deluxe head- versatile scanning functions, such as phones HS -6 Lightweight headphones memory channel and band scan, with HS -7 Mini- headphones. four types of scan stop. The RZ -1 is a 12 volt DC operated, compact unit, with built-in speaker, front -mounted phones jack, switchable AGC, squelch for narrow KENWOOD The RZ -1 wide -band, scanning receiver FM, illuminated keys, and a "beeper" to covers 500 kHz -905 MHz, in AM, and confirm keyboard operation. KENWOOD U.S.A. CORPORATION narrow or wideband FM. The automatic Optional Accessory 2201 E. Dominguez St., Long Beach, CA 90810 mode selection function makes listening PG -2N Extra DC cable P.O. Box 22745, Long Beach, CA 90801 -5745

Specdreatxons leatures and paces are subject to change without notice or obtlgat,on CIRCLE 41 ON READER SERVICE CARD

and you can too!

Andy is a Ham Radio operator and he's having with, Amateur Radio is the hobby for you. The the time of his life talking to new and old friends world is waiting for you. in this country and around the world.

You can do it too! Join Andy as he communi- If you'd like to be part of the fun ... if you'd like to cates with the world. Enjoy the many unique and feel the excitement ... we can help you. We've exclusive amateur bands ... the millions of fre- got all the information you'll need to get your quencies that Hams are allowed to use. Choose Ham license. Let us help you join more than a the frequency and time of day that are just right million other Hams around the world and here at to talk to anywhere you wish. Only Amateur Ra- home. Who are we? We're the American Radio dio operators get this kind of freedom of choice. Relay League, a non -profit representative organ- And if it's friends you're looking to meet and talk ization of Amateur Radio operators.

For information on becoming a Ham operator circle number 110 on the reader service card or write to:

225 Street AMERICAN RADIO RELAY LEAGUE Dewtington, Main

This space donated by this publication in cooperation with the American Radio Relay League. THE TM. B .I. R. D. Battery operated THE MAGAZINE FOR ELECTRONICS A LOMPU I f It ENTHUSIASTS InfraRed Detector MAY 1990 VOLUME 7, NUMBER 5 CENTRONICS PARALLEL IF introduces FEATURES Parts Express I' t the first Battery 7 is siditai operated InfraRed 16 Special Focus on Math -Solving Products: Detector pen. MathCAD v2.5, Derive v1.60 & CMPCALC4 This compact Math PC Software. device will Hewlett -Packard's New HP 48SX Scientific Calculator. instantly By Joseph Desposito confirm 24 24 An MC68701 Microcomputer Chip operation Programmer of infrared 01 Computer -controlled device programs the R2 MC68701 to customize it for your applications. emitting Li C9 R4 B. Beard C7 C8 r, - By Brian prod- 36 Electronic Controller for Slide ucts. v Projectors R3 Controls on /off of projector only when slide is J\ needed and provides fade -in /fade -out for smoother presentations. By David Pointing Indi- -1 R1 44 Extended Play Remote -Control System cates 44 (Conclusion) presence Operating and construction details for receiver of infrared module, system checkout and installation and use. By Crady VonPawlak in normal light. Slim 52 Interfacing 555 Timers ! Hands -on look at real -world use of this ubiqui- design easily tous and very versatile IC timer chip. reaches IR By Joseph J. Carr emitters on crowded VCR COLUMNS circuit boards. This 67 low cost and easy to 58 Electronics Notebook use instrument will Experimenting With Incandescent Lamps. soon become standard By Forrest M. Mims J!! equipment for all techni- 64 Solid -State Devices in the consumer Filters, FIFOs and Other Devices. cians By Joseph Desposito electronics repair 67 PC Capers industry. Laser Wars: Hewlett -Packard's New LaserJet CALL TOLL FREE III Laser Printer. By Ted Needleman 1- 800 -338 -0531 DEPARTMENTS

JEXPPeSS 6 Editorial rrrr ; By Art Salsberg 340 E. First St. 7 Letters Dayton. Ohio 45402 Phone: 513-222-0173 8 Modern Electronics News FAX: 513- 222 -4644 9 New Products 82 Advertisers Index ( IR( I I Nu. 163 'S FRET .INHIHM,4IIUN ( 4R11 16

4 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics EDITORIAL STAFF Art Salsberg CABLE -TV Editor -in -Chief Alexander W. Burawa Managing Editor Dorothy Kehrwieder Production Manager Elizabeth Ryan Art Director Barbara Terzo Artist Pat Le Blanc Florence V. Martin Phototypographers Hal Keith Illustrator BONANZA! t 10 OR Bruce Morgan ITEM UNIT MORE Photographer HAML IN MCC 300036 COHDED REMOTE CONVERTER (Ch .(only, 7900 180U Joe Desposito, Forrest Mims IH, PANASONIC WIRELESS CONVERTER lour best boy) 9800 7900 I.ne Ted Needleman, MOVIE TIME VR7200A (manual tune) 8800 6900 Curt Phillips ' JERROLD 400 COMBO 169 00 11900 Contributing Editors JERROLD 400 HAND REMOTE CONTROL 2900 1800 ' JERROLD 450 COMBO 19900 139 00 BUSINESS STAFF 'JERROLD 450 HAND REMOTE CONTROL 2900 1800 6300 Richard A. Ross JERROLDSB-ADD -ON 9900 ' JERROLD SB-ADD ON WITH TRIMODE 10900 7500 Publisher 'M-35 B COMBO UNIT I Ch 3 output only) 9900 7000 Art Salsberg 'M-35 B COMBO UNIT WITH VARISYNC 10900 7500 ' MINICODE IN-121 9900 Associate Publisher 6200 ' MINICODE IN 121 WITH VARISYNC 10900 6500 Dorothy Kehrwieder ' MINICODE VARISYNC WITH AUTO ON -OFF 14500 10500 General Manager ECONOCODE I minicod. subs10ute1 6900 4200 ECONOCODF WITH VARISYNC 7900 4600 Frank V. Fuzia 'MLD 1200.3(Ch 3outpul 9900 6200 Controller 'MLD -1200 21Ch 2outpuh 9900 6200 'ZENITH SSAVI CABLE READY 17500 12500 Catherine Ross INTERFERENCE FILTERS ,Ch 3onlyl 2400 1400 Circulation Director 'EAGLE PO 3 DESCRAMBLER ICh 3oulP l only 11900 6500 Melissa Kehrwieder 'SCIENTIFIC ATLANTA ADD -ON REPLACEMENT DE SCRAMBLER 11900 8500 Data Processing Kathleen Bell Output Price TOTAL Quantity Item Customer Service Channel Each PRICE SALES OFFICE Modern Electronics 76 North Broadway Hicksville, NY 11801 (516) 681-2922 California Penal Code #593 -D forb ds us SUBTOTAL from Shipping Add FAX: (516) 681 -2926 shipping any cable descrambling unit to anyone residing in the state of California. $3.00 per unit COD 8 Credit Prices to without notice. Jonathan Kummer subject change Cards - Add 5% Advertising Manager DI caec DDIAIT TOTAL Emily Kreutz Name Sales Assistant Address City

State Zip Phone Number ( C Offices: 76 North Broadway, Hicksville, NY 1 1801. Tele- Cashier's Check Money Order COD Visa Mastercard phone: (516) 681 -2922. FAX (516) 681 -2926. Modern Acct # Exp. Date Electronics (ISSN 0748 -9889) is published monthly by CQ Communications, Inc. Subscription prices (payable Signature in US Dollars only): Domestic-one year 517.97, two years 533.00, three years $48.00; Canada /Mexico -one FOR OUR RECORDS: year 520.00, two years $37.00, three years S54.00; For- DECLARATION OF AUTHORIZED USE - I, the undersigned. do hereby declare under penalty of perjury eign -one year 522.00, two years 541.00, three years that all products purchased, now and In the luture, will only be used on cable TV systems with proper $60.00. Foreign Air Mail year two years -one $75.00, authorization from local officials or cable company officials In accordance wan all applicable federal and $147.00, three years $219.00. state laws FEDERAL AND VARIOUS STATE LAWS PROVIDE FOR SUBSTANTIAL CRIMINAL AND CIVIL Entire contents copyright 1990 by CQ Communications, PENALTIES FOR UNAUTHORIZED USE. Inc. Modern Electronics or CQ Communications Inc. assumes no responsibility for unsolicited manuscripts. Al- Dated Signed low six weeks for delivery of first issue and for change of address. Printed in the United States of America.

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Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 5 SERVICING RF X1111 EDITORIAL i/IIII PRODUCTS Signals picked up by the low capacity input of Thanks for the Memories the Spectrum Probe allow rapid evaluation of problems. Simply placing the probe near a component allows judgment of whether it is We worry about U.S. dependence on for- joined the consortium. No Apple Com- active. RF failures are easily established. eign oil; on foreign minerals such as puter, Compaq or Sun Computer, among chromium; and so on. There isn't too others who declined to join the founders, 10dB much one can do about materials that we which included Digital Equipment Corp. per DIV don't have on our shores, of course. But and IBM. With the DRAM shortage production and quality of products that gone, so was any interest. The U.S. Gov- aren't dependent upon access to raw ma- ernment looked the other way, too, as terials is another story. So we also worry did other sources of financing. Finally, about our declining automobile industry, U.S. Memories called it quits as it entered 100 our disappearing shoe industry, our the Nineties still-born. µv Iiimarnmormo withering clothing industry, and our It's really shameful, I think. Such frequency 100 MHz beaten -down industrial machinery busi- shortsightedness will seriously hamstring nesses. What to do? future DRAM production -1 -Mbit and A cordless phone (base station) is probed near Kawasaki, Yamaha and Honda, among 4 -Mbit, onward to 16 -Mbit and 64 -Mbit. its 38.970 crystal in fig. 4. Both 39 MHz and its second harmonic are obvious. The lowest line others, caused much consternation a few It seems that we have lost the will or the at 10.245 is also obvious and can be estab- years ago when their hold on the motor- wherewithal to engage in large-scale the adjacent 10.2 crystal, lished by probing cycle industry appeared to be unbreak- semiconductor production battles, and which then shows 10MHz as higher level than 38MHz. We have established receiver RF able. Harley- Davidson, a subsidiary of will settle largely for niche production. oscillator /system operation in seconds with no AMF, and the last bastion of U.S. mo- Japan and Korea now own about 79 per- connection, information, schematic, etc.! torcycle makers, was going down the cent of the world's DRAM market. It's a drain. A group got together and bought market that will grow enormously in size 10dB the company, changed its production due to expanding applications, from per methods, and created a revitalized cycle high -definition TV to computer worksta- DIV maker that makes a profit and has moved tions. Moreover, the technology of mak- into the forefront of the motorcycle in- ing DRAMs is akin to that of producing dustry -all in a very few years. The cata- LCD screens, a product area that's ex- lyst was the U.S. Government, by the pected to burgeon. lt, too, requires lots 100 way, which helped out for a few years of money to be invested in production µv with a declining import tax on foreign - equipment. Will the U.S. walk away made cycles over a certain size. from this opportunity, too? Probably. frequency 100 MHz What has all this got to do with elec- All isn't lost in the memory world, say tronics? Well, it sort of parallels what some industry sages. We've got the lead 10dB happened in this industry. For example, in flash memories, which some think per a more important memory DIV from an $18 price to volume buyers in might become 1984, 256 -Kbit DRAMs plummeted to device. Specialty static and dynamic only $1.80 in 1987 -with immediate de- RAMs, too, are significant memory mar- livery. U.S. makers of dynamic random - kets that are not scary commodity -like access memories blithely dropped mak- products. Moreover, some U.S. compa- 100 ing these chips, accusing Japanese sup- nies are even slinking back to producing µv pliers of dumping. One year later, with DRAMs or leasing equipment for startup Texas Instruments and Micron Technol- companies to do the same. But money is frequency 100 MHz ogy the only remaining major U.S. still tight; industry leaders aren't much When the transmitter is activated (by pressing DRAM makers, the chips were being sold interested in cooperating with others; the near the 15.537 crystal pro- CALL), probing provides fig. 5. Fundamental operation and many for $4.50 with delivery ranging up to 20 government is still hesitating about harmonics are shown. As the probe is placed weeks! viding any industry assistance in what- near the following stages, the fundamental is ensure a supply DRAMs, a ever form. decreased, and the third accentuated until the To U.S. of relatively clean output of fig. 6 is obtained near consortium -U.S. Memories Inc. -was Viewing the recent U.S. Memories de- the antenna lead. The transmitter RF is visible formed in 1989 by seven computer and bacle, it'll likely be a long time before a in seconds! semiconductor makers. They anticipated similar venture is attempted. So I'd guess support by other U.S. companies, of that the DRAM market will remain a for- 107 SPECTRUM PROBE course, expecting some 25 or 30 more to eign- country commodity in the same way converts any scope Into a kick in some money and commit to buy- that oil is. And we'll just have to suffer 100MHz spectrum analyzer ing at least 20 percent of their DRAM the availability and price levels as eco- needs from the consortium. But as the nomic times dictate. whole thing was revving up, the shortage $199 direct of Japanese DRAMs began to subside by Smith Design 1324 Harris Rd. late 1989. From among some 60 U.S. Dresher, PA 19025 (215) 643-6340 computer companies, not a single one

CIRCLE NO. 167 ON FREE INFORMATION CARD Modern Electronics 6 / MODERN ELECTRONICS / May 1990 Say You Saw It In !llh/I LETTERS III

Reader Project Updates not in use. The original circuit equivalent through D3, Qb and D4, thus seizing the I enjoy the construction projects pre- is shown in Fig. 1. By adding three diodes phone line and causing a busy signal to be sented in Modern Electronics and some- per phone line, as shown in Fig. 2, the received by a caller on that line. times see ways to improve on a published full -wave bridge circuit created makes Thomas M. 'Gehl project. A case in point is the "Two -Line polarity a non-issue. Largo, FL Telephone Answering-Machine Inter- If the top line in Fig. 2 is positive, as re- face" that appeared in the February 1990 quired in the original circuit, when Qa issue. In the article, the author noted that and Qb conduct, current flows through We have two telephone lines and one polarity of the phone lines is critical. I D1, Qb and D2. Conversely, when the answering machine in my home. We've submit here a modification that creates a top line is negative (no current flows in looked in the past for a device that would bridge circuit for seizing the line that is the original circuit), current still flows enable us to have the answering machine pick up either line, to no avail. I gave up looking for a solution long ago. Then the "Two -Line Telephone Answering-Ma- chine Interface" that appeared in the February 1990 issue came along to solve the problem. However, while building the project I discovered two errors. One is that mention of C4 and R9 was omitted from the Parts List. The other is that J1 and P2 on the wiring guide were trans- posed. Unless this is corrected, phone line voltage from Line 2 will be fed into Line 1. Thanks for an interesting solution to my problem. Keep the useful projects coming. Kevin Fodor Akron, OH

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APPRECIATION DAYS. Everyone knows that there's a Mother's Day, Secretary's Day, and so on. But many people aren't so aware of special days that celebrate workers in the electronics industry. For example, Electronics Technicians are honored each year with a National Electronics Technicians Day in recognition of high performance standards maintained by these professionals. It's also a day (March 6) to commend the International Society of Certified Electronics Technicians (ISCET), which this year marks its 20th anniversary of certifying the professional capability of ETs. There were 27,578 certified techs at the end of 1989. (For info on the certification program, call 817-921 - 9101.)...Engineers celebrate their profession with a whole week (this year, February 18 -24) with National Engineers Week. Activities revolve around Discover "E, a nationwide program that provides hands -on engineering experiences to students through schools, museums and libraries. The Week is co- sponsored by the Institute of Electrical and Electronic Engineers (IEEE) association.

FCC PROPOSES CODELESS HAM LICENSE. With PR Docket 90 -55, the Commission proposed to amend its rules by establishing a codeless amateur operator license, the Communicator Class. The FCC proposal also included modifying the licensing structure to Communicator, General, Advanced and Amateur Extra Classes. Present Technician and Novice licenses would be grand- fathered indefinitely, but they will no longer be issued if the cited proposal becomes official. But under the new structure, you'd need a General- or grand- fathered Technician -Class license to communicate on popular 2- and 6 -meter VHF bands, where operators can reach a telephone number with a wireless portable or mobile rig and a relay -club membership.

PERSONAL COMPUTER TIDBITS. Maxell has introduced pre - formatted disks in the industry's four most popular formats....Ungar has a line of electrostatic dissipating (ESD) office and desk accessories, including various letter trays, desktop accessories, organizers, etc. The black- matte -finish products protect ESD- sensitive parts with Class 1, 2 and 3 sensitivity classifications (0 -1,999 volts; 2,000 -3,999 volts; and 4,000- 15,000 volts, respectively)....Safeware, the microcomputer insurance specialists, announced a new repair insurance policy for computers. Called "Safeware Fix:It," the policy insures against breakdowns as well as external losses and theft. The company offers a 20% bonus coverage for licensed, registered software....Geller Software Labs (Montclair, NJ) has the first spell- checking software aimed at database and spreadsheet users, and programmers. It's said to work with languages such as C, Pascal, BASIC. and others.

8 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics IIIiI NEW PRODUCTS II

For more information on products described, please circle the appropriate number on the Free Information Card bound into this issue or write to the manufacturer.

Soldering Station The Model SA -570 soldering station from OK Industries has an operating range of 600° to 800° F. This provides high power for multiple applications, including soldering circuit boards with exceptional thermal de- mands. A 70 -watt heating element with precise temperature control is

CGA- video, 80286-Based Laptop compatible external bidirectional parallel and RS -232C ser- Radio Shack's Tandy 2800 HD lap- ial. A socket is provided for an top computer is built around a low- 80C287 numeric coprocessor. Bun-

; power 80C286 microprocessor oper- dled with the system and installed on claimed to provide excellent stability ating at a user -selectable 6 or 12 the hard drive are Tandy's Desk - and repeatability and quick recovery MHz. Housed in an "executive Mate® Version 3.3 productivity on massive connections. In addition, black" case, the 2800 HD features a software, MS-DOS 3.3 and TEMM the directly grounded tip meets MIL - 9''/ x 8% -inch full -size electrolumi- (LIM 4.0). STD -2000 resistance and voltage re- nescent back -lit EGA -compatible su- An internal replaceable recharge- quirements. pertwist liquid -crystal display with able gel -type lead -acid battery is said This ergonomically designed sol- 640 x 400 -pixel resolution and 16 to provide up to 2 hours operating dering station has a low -profile, gray scales; an enhanced 84 -key key- time. This battery can be charged in- small- footprint housing that requires board with true 101 -key emulation side or external to the system, the lat- minimum - bench space. The hand mode and standard 3.5 -mm key- ter with an included external battery piece itself is light. A wide range of stroke; and the ability to exchange charger. Additional batteries are high -mass soldering tips are available batteries without turning off the sys- available as options, as are an inter- for the Model SA -570. $86.90. tem. Storage capacity is 1 MB of user nal 2,400 -bps modem, 1 -MB mem- CIRCLE NO. 122 ON FREE INFORMATION CARD RAM (expandable to 2 MB), an in- ory upgrade and choice of protective ternal 20 -MB hard Video Surround Sound -disk drive with carrying cases. 29 -ms access time; and one 1.44 -MB The computer measures 13.87 x Panasonic's Model SY -DS 1 digital 3.5 -inch floppy -disk drive. 12.25 x 3.25 inches (when closed) signal sound processor is said to give Ports available include EGA/ and weighs less than 12.5 lbs. $3,499. surround sound style audio effects to CIRCLE NO. 123 ON FREE INFORMATION CARD home video systems without the need

to require or add rear speakers to the video source that has audio output viewing area. The self -contained unit jacks or to a stereo receiver if the TV has a built -in amplifier, two speakers receiver is connected to an external and digital sound processor. In use, hi -fi system. the unit is placed atop or near the TV Internal circuitry sends a variably screen to obtain the surround -sound delayed audio signal throughout the effect. It can be connected to any listening environment. Effect inten-

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 9 NEW PRODUCTS ... sity can be adjusted, depending on the source and according to taste. Most four -speaker arrangements ELECTRONIC have a small "hot spot" in which the surround -sound effect is at its best. COMPONENTS According to Panasonic, the SY-DS1 is designed to expand this area to al- Whether you order 1 part or low more people to experience the ef- all 22,356.. _ MOUSER stocks fect of surround sound. $250. to meet your needs and.,, Can ship today" CIRCLE NO. 1240N FREE INFORMATION CARD Design Stations MOUSER also makes it easy. trol devices. The Model FA -154 s 1 , Wishmaker 1 and Wishmaker 2 from board's conversion speed is rated at Jameco Electronics are prototype de- 10 microseconds, and each of its sign stations designed to meet the eight input channels accept a 0 -to -5- needs of electronics engineers, tech- volt signal. An on -board variable - nicians and students. The two models gain amplifier permits reading of signals that are less than 1.2 mV (1 LSB). The board runs on most popular computers, including IBM PC- bus machines, Apple Ils, Commo- MOUSER dores, etc. Furthermore, serial inter- ELECTRONICS faces permit operation through any Sales 8. Stocking Locations Nalonwide computer's RS -232 port. $179.

CIRCLE NO. 126 ON FREE INFORMATION CARD CIRCLE NO. 146 ON REE INFORMATION CARD Frequency Adapter CONSOLIDATED to provide E L E C T R O N I C S A new adapter designed direct frequency readout on any multimeter is available from EXTECH Instruments Corp. (Waltham, MA). The converter provides frequency measurements over a range from 2 kHz to 20 MHz with a rated accuracy are said to simplify the building and of 1% of reading. Minimum sensitiv- testing of prototype analog (Wish - maker 1) and digital (Wishmaker 2) circuitry. Each includes a removable solderless breadboarding system, variable or fixed dc power supply, multiple- frequency signal generator, analog multimeter, fused overload protection, logic probe and more. THE ULTIMATE $199.95, Wishmaker 1; $249.95, ELECTRONICS Wishmaker 2. CATALOG CIRCLE NO. 125 ON FREE INFORMATION CARI) Order your 260 page catalog and price hot with over 14,000 money saving electronic parts and equipment! A /D Con verter Send 63.00 in a cheek or money order, or call 1-800 -643.3668 today and use your Mastercard or Visa. Alpha Products (Darien, CT) an- Consolidated Electronics, Incorporated 706 Watervliet Ave., Dayton, Ohio 46420-2699 nounced a high -speed 12 -bit analog - to- digital converter board that ex- Name pands its line of A -BUS devices for Address low -cost data -acquisition and con- City State Zip

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ity is rated at 100 mV rms from 2 kHz frequency bands: Band 1 -29 to 29.7 to 10 MHz and 200 mV from 2 MHz MHz 10-meter Amateur, 29.7 to 50 to 20 MHz. Overload protection is to MHz vhf low and 50 to 54 MHz 6 -me- 500 volts ac and dc. ter Amateur; Band 2 -136 to 144 The adapter attaches to any multi - MHz military land mobile, 144 to 148 meter via banana plugs. The user MHz 2 -meter Amateur, 162.4 to simply sets the multimeter to the 200 - 162.55 MHz weather and 148 to 174 mV dc range and selects the frequen- MHz high; and Band 3 -400 to 406 cy range to be measured via a rotary MHz weather, 406 to 420 Federal switch on the converter module. The Government, 420 to 450 70 -cm Ama- supplied test leads then plug into ba- teur, 450 to 470 uhf and 470 to 512 nana jacks on the adapter and are MHz uhf T. assembler or C to produce applica- used in the normal manner. The only A companion hand -held scanner, tion programs, the IR Remote Con- other control on the converter is a the Model SR -11, also features the troller comes with a cable to connect HI /LO TRIG LEVEL slide switch. Sepa- Express Tuning System, 10- channel it to the parallel printer port of an rate POWER and Lo BAT indicators memory and same frequency cover- Amiga 500 or 2000 (the Amiga 1000 are provided. age as the desktop unit. It uses four requires an optional adapter), two The converter measures 3.6" x AA alkaline or rechargeable cells. cables for connection to a videocas- 2.8 " x 1.6 " and comes with a 9 -volt $149.95, Model SR -901; $189.95, sette recorder, a 3.5 -inch program battery and a pair of test leads. $49. Model SR11 disk and user's manual. Power for the Controller is pro- CIRCLE NO. 127 ON FREE INFORMATION CARD CIRCLE NO. 12! ON FREE INFORMATION CARD vided by four AAA cells. It draws less than 50 mA from the Amiga Programmable Scanner IR Remote Controller For Amiga Computers computer. $180 plus $5 shipping. New from Cobra Electronics, the CIRCLE NO. 129 ON FREE INFORMATION CARD Model SR 901 desktop scanner offers Edu -Vid Research's (Pembina, ND) IR Remote Controller is primarily a programmable for up to 10 channels. Probe It features Cobra's Express Tuning hardware package for use with Com- Magnetic Sensing System that replaces the multi -but- modore Amiga personal computers. The Lil DevilTM Mag -Probe from ton keypad with a three -button (up/ (A model for use with IBM and com- HUB Material Co. (Canton, MA) down /fast) design that simplifies patible computers is soon to be avail- detects residual magnetism and tran- able.) It allows a VCR or any other sient current pulses ( "glitches ") as infrared remote -controlled device to fast as 10 milliseconds and identifies be operated by a user's program. The north and south poles in ac- and dc- Controller can learn the IR pulse powered solenoids, relays and any codes from the remotes of most de- other electromagnetic device. There vices. It can also detect when a VCR is actually sending a video signal and, with suitable monitors, can switch the screen from computer output to video output. In addition, "touch tones" can be placed on a tuning and programming opera- video tape for the Controller to de- tions. The uncluttered control area tect and its program do various contains a large rotary volume /pow- things. These include mix the er control and nine -decade LCD dis- Amiga's sound or voice with the vid- play of tuned frequencies and operat- eo sound or overlay computer output is no need to refer to a schematic dia- ing status. on the video output (if a separate gram when troubleshooting a device Features of the new scanner in- Genlock is used) or simply stop the under test with the Lil Devil. One clude: one -touch memory program- video while the computer outputs to just positions the probe tip close to ming; automatic scanning and manu- the monitor screen. the coil in the device. A LED in the al tuning; channel lockout; automat- Software provided with the pack- handle of the Lil Devil lights if the ic squelch; telescopic antenna; and age is intended to demonstrate the device is energized. No electrical small 71/ -inch square footprint. The product's many uses. Meant mainly connection to the circuit or device scanner provides coverage in three for people who program in BASIC, under test is required.

You Saw It In Modern Electronics 14 / MODERN ELECTRONICS / May 1990 Say Two models are available. The is 8 input power is 5 pedance ohms, 60 -MHz Oscilloscope standard -sensitivity model tests large watts minimum and 45 watts maxi- and standard -size solenoids and re- mum and efficiency is rated at 85 dB Beckman Industrial's new Model

lays. The high- sensitivity model tests at 1 watt at a distance of 1 meter. 9106 three -channel oscilloscope of- the full range of devices, down to Both speaker systems are available fers a 60 -MHz bandwidth and the subminiature reed relays. in black or white enclosures and ability to display eight traces on- hardware. Model $150, screen. Its third channel provides a CIRCLE NO. 130 ON FREE INFORMATION CARI) $300, SB30; Model SB10.

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( I RCLE NO. 165 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 15 Technology Enhance Your Math Prowess With Software & Hardware Computer software and hand -held calculators ease the burden of complex calculations in different ways. Here are in -depth examinations of such products that reveal their strengths and weaknesses.

By Joseph Desposito

-4 -_. -_ lt( --)--4- Mathematical Software For PCs

Anyone who designs elec- cal software often can display formu- Cambridge, MA 02139; 800-MATH- tronic circuits invariably las the way you are used to seeing CAD), the one that is most enamor- finds himself dealing with them in textbooks and journals. This ing is its ability to make the display mathematical equations. Usually, makes it possible to present design on your computer resemble a page these are solved with pen and pencil, equations to others in a way that is from an electronic design text or scientific calculator or computer (or easily understood. journal. MathCAD, which has a sug- some combination of each). Those The programs we review in the fol- gested retail price of $495, can inte- who use a personal computer have at lowing pages are MathCAD v2.5 grate equations, graphs, text and fig- their disposal a variety of ways to from MathSoft, Derive v1.60 and a ures on your computer display -and tackle mathematical equations. One brand new program called CMP- the equations and graphs are live! way, and probably the most popular, CALC4 from UDH Enterprises. This means you can assign values to is with a high -level programming lan- There are many others, of course, the variables of an equation to obtain guage, such as BASIC, Pascal or but these are representative ones. results, graph those results automat- FORTRAN. Another is with a After we review the math soft- ically, and then, if desired, change spreadsheet program, such as Lotus ware, we'll take a look at a new prod- the variable values to obtain new re- a new graph. 1 -2 -3. A third way is with mathemati- uct from Hewlett- Packard, the HP sults and cal software, which is the method we 48SX scientific expandable calcula- Besides the main program, Math - are concerned with in this article. tor. Besides the regular features of a Soft also sells applications packs for Mathematical software has certain scientific calculator, it has graphics a variety of disciplines. The price of advantages over other computerized features that make it competitive the Electrical Engineering Applica- methods of solving electronic design with math software for the PC. tions Pack (see sidebar) is $99. equations. For starters, this type of software eliminates the need for pro- MathCAD Operation gramming. Another advantage is MathCAD version 2.5 that the formulas for problem -solv- Softwarefor creating formulas MathCAD for the IBM PC and corn- is also avail- ing methods, such as matrix algebra, that look good -calculate, too! patibles (the program are built in. Also, some of these pro- able for the Apple Macintosh) comes grams are capable of doing calculus, on two 5.25 -inch disks or one 3.5- included which is beyond the scope of pro- Of the many virtues of MathCAD inch disk (both formats are 201 Broadway, in the package). To install the programs like 1 -2 -3. Finally, mathemati- v2.5 (MathSoft,

It In Modern Electronics 16 / MODERN ELECTRONICS / May 1990 Say You Saw 11111I11"ERN ics May 1990

gram you simply copy the files to your hard disk. FILTERING A NOISY SIGNAL WITH FFT

MathCAD's opening screen dis- Define tae signal: 1 :- 0 ..127 plays its logo and the directive "Press q sine --- 14 n coal n, F1 for help." Unfortunately, it's not i L1ze 1128 I immediately evident from the help screen how to access the program's main menu, or how to issue commands. If you use the documentation, you have to leaf through a few pages before it tells you to press F10 to access the main menu. Learning to s .. q rnd(2) 1 use the program is rarely an intuitive, t i trial- and -error experience; it is most- 6 ly it in - r' r+. , a "look up the documenta- s `,1/,.^. / r^M,v,.'r..rJ t I.w.,. tion" one. Everything you do in MathCAD- -6 formulas, place text or sketches enter Fig. 1. In MathCAD, definition signs (: =) are often used instead of equal (_ or produce graphs -you do free- signs. form, on a display that emulates a scratchpad. To move around the scratchpad, you use the cursor keys or issue a "go to" command with the If you press F10, a horizontal menu in a textbook or professional jour- coordinates of the desired position. is displayed across the top of the nal. Whereas most spreadsheets or This is a cumbersome way to do screen. When you select a menu item, programming languages use an aster- things and is one of the least- appeal- such as System, a drop -down menu isk ( *) for multiplication, a slash (/) ing features of the program. Once appears with several choices. If for division, and a caret ( A ) for ex- you reach a desired position, you en- you're working on an XT -class ma- ponentiation, MathCAD uses tradi- ter a formula, for example, by typing chine, the first thing you'll notice is tional mathematics symbols. Addi- numbers, letters, mathematical oper- how long it takes for the program to tionally, MathCAD has symbols for ators or math symbols. The program draw the menu box. This is the first integrals, derivatives, sums, prod- requires that you define variables be- indication of how incredibly slow the ucts, square roots, subscripts, abso- fore you use them in a formula. This program can operate at times. Al- lute value, Greek letters and others. is done by typing the variable name though you can use the program on a One symbol MathCAD uses is not followed by a colon and a number. dual -disk IBM XT -type machine, a common math symbol. MathCAD Math symbols are created with you'll be much happier using it with distinguishes between an equals sign keyboard symbols or with Alt -key the fastest machine and fastest hard ( = ), which is the signal to calculate a combinations. For example, an inte- disk you can lay your hands on. And result, and a definition sign (: = ), gral sign is created by typing an am- throw in a math coprocessor for which tells the program the value of a persand ( &), and a "less -than or good measure. variable. The definition sign is en- equal -to" symbol is created by typ- If you press ESC, rather than F10, a tered by pressing a colon (:), but it is ing Alt -(. To distinguish explanatory command line appears instead of the displayed on the screen as a colon text from text used to represent vari- horizontal menu. Anything you can plus an equals sign. If you want to enables, you alert the program by first do with the menu, you can do with ter an equation such as d = v *t, typing quotes. You place a graph on the command line. Some commands rather than v *t = 50, you normally the display by typing the sign. can be issued from the keyboard, use the definition sign. Thus, if you MathCAD refers to each equation, too, as Ctrl- key sequences. look closely at a MathCAD screen, plot or block of text you enter as a re- such as the one shown in Fig. 1, defi- gion. If, after you have created an nition signs predominate. equation, plot or block of text, you MathCAD Features You can specify a range of values don't like its placement on the The most striking feature of Math - for a variable by entering an expres- screen, you can move it (the region) CAD is its ability to display an equa- sion such as t: = 1..100 (an increment by cutting it from one part of the tion on the screen that essentially can also be entered). The program screen and pasting it to another. looks like an equation you would see will calculate a set of answers and

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 17 present them in a table, create a two - and change the vertical scale. Besides stored in a text file, or use an IF func- dimensional plot, or both. Math- entering a range of values from the tion and relational operators to test a CAD can also create surface plots, keyboard, you can also enter values condition and change the behavior of such as the one shown in Fig. 2. stored on -disk in an ASCII file. This an expression based on that condition. To create a surface plot you must is about as close as you can come in MathCAD has built -in units for specify a range of values for two vari- MathCAD to executing a program mass, length, time and charge. To at- ables. Once you create a plot, you loop. Other programming -like fea- tach a unit to a number, you simply can size, rotate or tilt it, hide lines tures let you issue a set of commands multiply the two together. You can

MathCAD EE Applications

The MathCAD Electrical Engineering Applications Pack consists of a disk with 19 applications files, a file of units N' definitions, sample data files and a 120 - The coefficients of the numerator are: e .- M i i' (N - i)' page user's guide. The applications carry out common design calculations from several different branches of elec- To find the impulse response h for this filter, first find coefficients for Math - trical engineering and employ the partial fraction expansion of the transfer function H: CAD's complex arithmetic, matrix operators, equation solving and plotting :_ .001 capabilities. Topics covered in the applications pack include antennas and 1 ¡'2 rz + a 1 r exp(j 8) dd circuit analysis, transmis- K := J 8rr exp(j A) waveguides, k 2 a 0 l kJ sion lines, filters, coding and signal processing, and transfer functions for con - [Ctrl)(PgDn] trol theory. K are: You can load and run applications in H expanded in partial fractions is: The coefficients other the pack just as you would any K K MathCAD documents. The applications k k o - 0.0911 solution methods, H(z) .= M + -0.215 implement common 0.692 - 1.3011 ' z - a and the documentation provides a brief k k 4.03 + 2.56i background for the application. -6.164 + 8.384i -12.936 - 10.8191 idea what one of the The beginning of the infinite To give you an of impulse response h is given by: 14.593 - 15.474i applications looks like, we've included 14.593 + 15.4741 -12.936 + 10.819i part of the "Design of an IIR Filter" m := 0 .80 \ m-1 -6.164 - 8.3841 application here. The application de- h = M h .= ) K a 4.03 - 2.561 signs a low -pass digital IIR filter of the 0 m / k k 0.692 + 1.3011 -0.215 + 0.0911 Butterworth type. The user specifies the k minimum stopband attenuations and (Ctrl]]PgDn) defines the width and location of the Plot of impulse response: transition band by specifying the pass - band and stopband edge frequencies. 0.4 MathCAD calculates the required filter order and constructs the transfer function. The routine provides coeffi- h ,0,h m m cients for the transfer function and for its expansion in partial fractions, from which the impulse response can be cal- -0.2 culated. The application also finds the in 50 filter output for some simple input sequences in two ways: by direct convolu- tion with the truncated impulse response, and by using a difference equation based on the transfer function coefficients.

Electronics 18 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern .Su processor installed in your computer) SURFACE PLOT z M 29 I 9 ..M and the way it forces you to cursor f(x.y) : sin lx y 1 Local Surface Format 1 around the screen to place equations, x -1.5 .15 i y . -1.5 .1 notation - ie i .1 Tilt - 35 text, graphs and figures in a docu- Hidden Linea n Vertical Scale 29 ment. This program sorely needs a Global Default Revert mouse for navigation. Other prob- ' fitRlr Done lems with MathCAD are its inability M+taf#Kyr,l... r rr ...: to perform symbolic math and its 11Pw'=:__ '44 lack of a true programming language. yj,;.....;++10+1 At a price of almost $500, Math- 1/ CAD is for engineers or educators with high -powered PCs who not only need a program to solve problems, M but also need one that can generate high-quality technical documents.

Fig. 2. A surface plot created with .MathCAD. Derive v. 1.60 Getting an A + in symbolic math also define your own units by using PCs and XTs. It does. MathCAD the definition sign. cannot do symbolic math. Anytime It's hardly a surprise when a comput- MathCAD has 67 built -in math you want MathCAD to solve an er program spits out the answer to a 232 functions, including Bessel func- equation, it attempts to calculate a math problem such as in a fractions, fast Fourier transforms, vec- numerical answer. Thus, you usually tion of a second. It is a surprise, how- tors and matrices. Any calculation need to provide values for all con- ever, when a program can perform a you can perform in MathCAD on stants and all but one of the variables relatively simple mathematical exer- single values, you can also perform in an equation. cise such as finding the factors of x2 with vectors or matrices of values. MathCAD's 262 -page user manu- + 2x + 1. In the first case, the solu- Since you can insert figures on the al is very nicely done, often including tion depends on number crunching, MathCAD scratchpad, you might one or two screen shots on a page to something computers do exceedingly think that the program has built -in explain operation of the program. well. In the second case, the solution drawing functions. This is not the Also included is a Reference manual depends on something else, and only case. If you want to use a figure in a and a Quick Reference manual. What a program that performs symbolic MathCAD document, you must cre- is missing, however, is a Quick Start math can give you the answer. Derive ate it in a drawing or CAD program section in the manual. from Soft Warehouse (3615 Harding that can create HPGL (Hewlett - Ave., Suite 505, Honolulu, HI 96816; Packard Graphics Language) files. 808 -734 -5801) is a program that can & You can then translate the file into Comments Conclusions do symbolic math, just as its prede- MathCAD sketch format and import With its beautiful displays as an in- cessor MuMath did, and can crunch it into a document. ducement, MathCAD can easily lure numbers, too. Derive is for the IBM To enable you to print out your you into giving up your old calcula- PC and compatible computers, re- journal -like documents, MathCAD tor, spreadsheet or self- written pro- quires 512K RAM, and has a suggest- supports most popular printers and grams. And for some, the switch to ed retail price of $200. plotters, including postscript print- MathCAD may prove very satisfy- ers. And as if this weren't enough, ing. MathCAD is a full- featured and Derive's Operation MathSoft devotes 18 pages of the powerful program that especially ex- Reference manual to describing its cels in its a3ility to display equations Derive, which comes on a single 5.25 - printer and plotter drivers so that you in mathematical notation and solve inch 360K floppy, is a menu -driven can add your own, if necessary. and graph those equations. What system. When you start the program, At this point, you may be wonder- you may find distracting, though, is the opening screen is divided into two ing if MathCAD has any drawbacks the speed at which it operates (espe- areas by a horizontal bar. The bot- other than its sluggish operation on cially if you do not have a math co- tom portion (last four lines) of the

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 19 i power, such as x2, you enter it as x 2 at the menu prompt -the program displays the variable with a super- script in the algebra window. One thing the program does not do, however, is display subscripts. The algebra window remains in effect until you choose Plot from the menu. Then the work area changes to a plot window. One of the slick features of the program is its ability to

SIM (3 x) SIM (5 x) SIM (7 x) open several windows and mix alge- 1: SIM (x) windows on the screen at 3 5 7 bra and plot the same time, as shown in Fig. 3. To 2: p from the soLue Manage do this you choose Window COMMAND: Author Build Calculus Declare Expand Factor Help Jump Options Plot Quit Remove Simplify Transfer molle Window main menu. option Enter Derive Algebra easily User Pree:fift Though most operations are accessed from the main menu, some Fig. 3. Derive lets you mix algebra and plot windows. are inexplicably hidden away in sub - menus. For example, once you enter an expression, it's likely that you'll To screen contains the menu, a prompt expression, the entire entry is high- want to evaluate it at some point. to figure line and a status line. The first menu lighted. You can change the high- do this, however, you have is in you encounter contains 19 choices in light, however, with the cursor keys. out that the Substitute command two horizontal rows. You make a se- You can highlight a portion of an en- the sub -menu of the Manage com- lection by typing a single letter (usu- try, or you can move the highlight to mand -not very intuitive. Or some- will you an ally but not always the initial one) of another entry. times the program give the command, or by moving the Eight of the menu choices directly answer like ' %,. If you want the deci- highlight with the space bar or tab affect entries in the work area. Some mal form of the answer, you have to find Deci- key (not the cursor keys) and pressing choices, such as Plot, operate on high- scout through the menus to sub -menu of Notation, the Enter key. lighted entries or parts of entries. For mal as part of a The first choice on the menu, Au- example, if the equation y = 2x + 3 which is part of a sub -menu of options. can explana- thor, lets you enter mathematical ex- is highlighted, and you choose Plot, Although you enter pressions or equations into Derive. the program draws the graph of the tory text and text expressions in for- When you choose Author, the menu line y = 2x + 3. However, if you mulas, it is not readily apparent how Word from disappears and a prompt appears. highlight only 2x, the program draws to do so. You must choose You can enter an expression, such as the graph of y = 2x. Other choices, a third -level menu after selecting Op- tions and Input. Or, you can couch 53 * 12 or 2x + 3 or an equation, such such as Factor, prompt you for the the quotes as y = mx + b. A nice feature of the number of the equation that you your text within quotes, but math program is that it understands impli- want to work on. remain with the text. To access cit multiplication. In other words, if When the work area is first dis- symbols such as pi, theta and others, you type two consecutive letters, the played, it is referred to as an algebra you enter alt- letter combinations. program assumes you want them window. This means that equations multiplied together. After you type or expressions entered in the menu an expression, you press Enter, and area are transformed to look like Derive's Features the program moves it above the hori- equations or expressions from a text- zontal bar that divides the screen. book or journal. For example, when Derive is a crackerjack with symbolic makes it very This upper portion of the screen is you enter an integral at the menu math. The program known as the work area. Each ex- prompt, you do it by typing INT fol- easy to simplify, factor and expand solve equations pression in the work area is given a lowed by a mathematical expression. expressions, and to number, and the most recent entry is However, when the program moves for one variable in terms of another. plotting. highlighted in reverse video. this entry to the work area, it displays The program also excels at to The program's use of reverse video a standard integral sign. Or if you Derive makes it a simple matter three -dimensional is interesting. When you first enter an want to enter a variable raised to a plot two- and

20 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics graphs, and to plot more than one written and easy to understand, but it 89701) that turns your PC into a graph on an x -y (two -dimensional) could use more sample problems. complex number calculator. The axis. There are also features that let program, which has a suggested re- you maneuver the plot after it is con- Comments & Conclusions tail price of $39.95, was written by an structed, such as a zoom feature. One electronics engineer to assist in per- Derive, which Soft Warehouse calls a thing you can't do is print plots di- forming analysis of feedback cir- mathematical assistant for your per- rectly from the program. cuits. A subset of the program, called sonal computer, is a well- rounded Derive can do arithmetic, algebra CMPCALC3, is available free from program that can perform many and calculus, and it can work with the author for a $5 shipping and han- mathematical functions. The menu vectors and matrices. To facilitate dling charge. system, in general, is easy to learn this, the program includes over 100 and use, and the algebraic display is built -in functions that cover areas LC4 first rate, except for the omission of CMPCA Operation such as exponentials, logarithms, subscripts. Derive doesn't offer spe- When you load CMPCALC4, a sin- trigonometry, complex numbers, cific solutions for electronics, such as gle prompt line appears on your probability and statistics and others. a file with electronics units or a file screen. It says: Enter Cmplx no. or If you need a function that the pro- full of electronics equations, but order ( "H" for help). Entering a gram doesn't address, it's easy these can be entered by the user. complex number, such as 4 + 2i, enough to define it by selecting De- Derive does many things, includ- gives you an error message and re- clare from the main menu. ing symbolic math, and does them turns you to the prompt; entering If you're interested in using units well. Although it lacks programming "H" gives you a help screen loaded of measurement or physical con- features, it's still an excellent pro- with too much information. Fortun- stants in your equations, some are gram for general mathematical use ately, the user manual, which is 16 available in separate files supplied and should be seriously considered sheets of paper stapled together and with the program. To use them, you for specific electronics work, too. printed on front and back does a bet- merge files into the current alge- the ter job of getting you started. bra window. If the units or constants The manual explains that the pro- you want aren't available, you can CMPCALC4 gram simulates an RPN (reverse Pol- enter them by selecting Declare from ish notation) calculator for complex the main menu. A calculator for complex numbers. To enter a complex num- Derive performs the majority of its computing ber, you simply type in the real part, math functions within a fraction of a hit the space bar, type in the numeri- second, without the help of a co -pro- CMPCALC4 is a new program from cal value of the imaginary part, and cessor (which it will not use, even if UDH Enterprises (1000 E. William press the Enter key. The program then you have one). Operations such as St., Suite 100, Carson City, NV puts the number on the top of the certain three -dimensional plots, however, can take several minutes to complete. Loading files from disk is also time -consuming, taking almost ENTER CMPLX MO.OR ORDER ("H' FOR HELP) a a file with 40 minute to load entries. 2.0000088000E +69 3.6709680608E +89 Other features of the program in- 6.8980000088E+9B 6.9009669969E +69 4.0086696000E +09 3.6606686966E+96 clude exact arithmetic to thousands of digits, approximate arithmetic to a desired degree of accuracy and inte- ger factoring. A major drawback of Derive is the lack of a programming language or any way to do recursive calculations. And there isn't any way to enter a range of values into an equation to get a range of results. To get you up and running, Derive 2.8888899660E+00 3.67969BB690E+90 A has a 126 -page user manual, on -line help arranged by topic and nine Fig. 4. When you store a variable in CMPCA LC4, it appears at the bottom of the demo files. The user manual is well- screen with its name beside it.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 21 A Guide to Selecting Math Software and Hardware

In the accompanying article, we reviewed three math programs that run on Comparing Product Features the IBM PC and compatibles, and in the MathCAD Derive CMPCALC4 HP 48SX follow -up article also reviewed a new Features scientific calculator from Hewlett - values 5 0 0 o Packard. If you're in market for one of Calculates range of 0 5 0 3 these or a competing product, it's likely Performs symbolic math 0 5 0 n that you're interested in some or all of Factors equations 4 5 0 4 the features listed in the Table presented Finds roots of an equation numbers 5 4 5 here. The Table gives a "snapshot" of Handles complex 4 0 how each of the products reviewed here Does matrix algebra 5 5 5 t) stack up against each other. Each fea- Does unit conversions 2 0 2 ture is given a rating from 0 to 5, where Programmability 2D plots 5 5 0 0 is the lowest rating and 5 is the highest. 3D 4 4 0 o To give you an example of how we plots 4 0 4 rated each feature, take a look at "Pro- Displays math symbols 5 4 0 2 grammability." The HP 48SX has a Displays explanatory text 5 5 2 0 2 fine programming language; so it re- Prints a document modules 5 0 0 4 ceives a 5. MathCAD and CMPCALC4 Electrical engineering $495 $200 $39 $350 don't have a language but let you run Price commands automatically -this gets them a rating of 2. Derive has neither a programming language nor a way to ex- you'll notice that Derive receives a 5, gram, the Table can help you in your ecute commands automatically, so it due to its excellent implementation of decision. receives a O. If you're interested in the this feature. The HP 48SX receives a 3 The Table can also assist you in programming capabilities of the prod- because the feature is useful but has choosing products other than the ones uct, you could use this information to some drawbacks, as noted in the review. reviewed here. Just use the features in guide your choice of product. If, on the The other programs receive a 0 because the Table -along with others that may other hand, you're more interested in a they lack this feature. Again, if this is a interest you -as a product selection program's ability to do symbolic math, feature you want to see in your pro- checklist.

stack, or storage area -the number label name beside it, as shown in performs complex exponential, loga- appears on the screen just below the Fig. 4. You can store up to nine num- rithmic, trigonometric, hyperbolic cursor prompt. bers in this area, and an additional 41 and square -root operations. The pro- When a second number is entered, more that are not displayed. gram also has a few functions that it it replaces the first on the top of the If you want to automate proce- can perform, such as DUP (dupli- stack, and the first is moved down dures, you can do it by entering MEM cate), SWAP and swi (switch). one place. To perform a mathemati- at the prompt. CMPCALC4 lets you Automated procedures can use cal operation on the two numbers on enter up to 500 steps and save them to any command that can be entered at the stack, you enter the operator at a disk file. To re -run the sequence of the prompt, plus a few others, which the prompt. The answer, which ap- steps, you load the file from disk with amounts to about 12 commands in pears instantly, then moves to the top the LOAD command and then enter all. There is also a way to call one file of the stack and the other numbers the RPT command. from another and to designate a file are erased. All numbers on the stack as a subroutine. Although the author states that CMPCALC4 has a pro- are displayed in scientific notation CMPCALC4 Features with 10 decimal places. gramming language, there are no If you want to store a number, you The obvious highlight of this pro- conditional, testing or looping com- enter it and then enter a command gram is its ability to perform mathe- mands available. such as STO A (where A is a label). matical operations on complex num- Included on the CMPCALC4 disk The number appears in a storage area bers. Besides the four main opera- are three other useful programs: at the bottom of the screen with the tions ( + , , * and /), the program EDCALC4, QUINT, and POLSLV.

22 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics EDCALC4 is a text editor for the and gives some valuable examples has several limitations, it's true - procedures you create with CMP- from the author's engineering experi- namely, the user interface, an exclu- CALC4. QUINT is a program that ence. In one example, he explains sive use of scientific notation and solves up to fifth -degree polynomials how the program can help you plot lack of printed output. But with real coefficients. POLSLV is a amplifier characteristics and Nyquist CMPCALC4 is easy enough to learn program that solves up to 20th -de- diagrams. However, the program it- and use -with the help of the manual gree polynomials with real coeffi- self doesn't permit the user to do any -and contains enough features to cients. The difference between plotting or printing. enable you to perform calculations QUINT and POLSLV is the ap- and create automated procedures. proach used to solve the polynomials. Thus, if you work with complex Comments & Conclusions Although the user guide isn't pro- numbers all the time and don't have a fessionally printed and contains CMPCALC4 is a specialized tool satisfactory tool to deal with them, some punctuation errors, it does a that can help you deal effectively CMPCALC4 is a good low -cost good job of explaining the program with complex numbers. The program choice for the job.

H -P's Newest Scientific Calculator For electronics engineers, tech- i nicians, educators and students involved in electronics, calculator is an indispen- Analysis a scientific Method of Waveform sable tool for solving problems. Fourier

These calculators have been around 11 I. I I.IN,In for many years, but it seems that each time a new model appears it has more features than any preceding it. This is just the case with the HP 48SX, the newest entry from Hewlett- Packard, a company known for its leadership position in this field. In fact, the HP 48SX combines the best features Vunplc ..oi b. ..,1, found in two earlier Hewlett -Pack- ;111u Ih.41,1,.. It has .,,. ard products. the calculation .,, ,hcn .y. . ,.I and graphics capabilities of the HP I, , ml,s ', Inl 28S and the flexibility and expand- 1,1 v1mg Ow, 1,1r f ability of the HP 41. The HP 48SX, called a scientific expandable calculator, has advanced be I555511,.r features that let you enter equations euitm. In IIIr n.d 1 just as you would see them in a text- am paru,, I exI.I. .,l I,r %salt, In book or journal. It also allows you to manage unit conversions, such as ><.,a ,I% t,n1 changing feet to meters. These ad- 1 . 11 , I IN n, ..,11, .olr..d ili n ,nln. 1 vanced features complement a long d'b, ih, iI.d IhC d,,' l,n,l.un, 1, .I I,in,l.,nw ,ul. .,d. 1, IP. Mai list of others, which are packaged in a F .. . Inl,,s.,l unit that includes 256K ROM, 32K RAM, an 8 -line by 22- character super- twisted liquid- crystal display (Continued on page 70)

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 23 Project An MC68701 Microcomputer Chi p Programmer A computer- controlled device for programming the MC68 701 to customize it for your application

By Brian B. Beard In the past April issue, we fami- liarized you with the features and functions of the 68701 single -chip microcomputer IC in enough detail for you to utilize it in your own projects. This month, our discussion focuses on a programmer that permits you to program the on -chip ROM built into the 68701. Programming single -chip microcomputers can present major problems because the unusual pinouts used make them incompatible with standard EPROM programmers. Low - cost programmers often require the additional steps of first programming a 27XX series EPROM first. This EPROM is then used to transfer on -board data to the single -chip microcomputer chip. The two -step process can be annoyingly slow and requires the use of two programmers. In contrast, the Programmer to be described is the only one needed to program the 68701 chip. It is flexible, fast and easy to use as well. Operated from a single 5 -volt dc supply, it features its own dc-to-dc converter that provides the 21 volts required for beled CPU. The heavy lines routed U8 begins in mode zero, the only successful programming. Light -emit- from the CPU to the LED INDICATORS mode that allows the EPROM to be ting diodes indicate the status of the and PRINTER PORT blocks indicate an programmed. Instead of fetching the programming process, and a parallel eight -line bus. All other lines indicate reset vector at $FFFE, U8 fetches the printer port permits connection to single- conductor lines between the starting address from $BFFE in virtually any personal computer. various elements that make up the mode zero. Programmer. Table 1 shows the memory map of About the Circuit Figure 2 is the schematic diagram the Programmer. The operating pro- cir- gram and interrupt vectors are pro- Figure 1 is a block diagram of the va- of the Processor and Memory rious elements that make up the Pro- cuits. Microcomputer chip U8 runs grammed into 2764 EPROM U6. grammer. As you can see, at the heart the programming process. When This program determines the 68701 version) of the six basic blocks is the one la- power is applied to the Programmer, type in use (standard or U4

Electronics 24 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern 3(B), is RS- 232 -compatible, which makes it usable with just about every 68701 68701U4 personal computer now in use. MAX232 serial chip U4 contains two $0000 -$001F MPU Registers (68701) RS -232 drivers, two RS -232 receivers $0020-$007F $0020-$003F Unused and an on -chip charge pump. The $0080 -$00FF $0040-$00FF Internal RAM (68701) charge pump uses the 5 -volt dc sup- s $0100 -$5FFF Unused ply line to generate the bipolar volt- $6000 -$7FFF Printer Port Input ages required by the RS -232 drivers. $8000 -$9FFF s External RAM (6264) Listed in Table 2 are the pinouts $A000 -$BFEF External EPROM (2764) for the serial connector on the Pro- $BFFO -$BFFF s External Interrupt Vectors (2764) $C000 -$DFFF s LED Output grammer. No handshaking controls $E000 -$F7FF $E000-$EFFF Unused are actively controlled by the Pro- $F800 -$FFFF $F000-$FFFF Internal EPROM (68701) grammer, and DTR is not connected (and is, thus, ignored) by the Pro- grammer. DSR and DCD are wired to and adjusts the size of the buffers in success OKAY or a failure FAIL, with the "on" condition, or + V, at all 6264 RAM US accordingly. green indicating success and red indi- times. RTS is received, buffered and The status of the programming cating failure. For LEDI and LEDS, looped back to the host at CTS, which process is indicated by light- emitting the function is ERASED; LED2 and makes CTS track RTS. diodes LEDI through LED7 in Fig. LED6, LOAD; LED3, PROGRAM; and Baud rate of the Programmer is se- 3(A). Each pair of LEDs is assigned a LED4 and LED7, VERIFY. lected with jumper network JP2, different function to monitor and re- In this Programmer, the Serial while jumper JPI permits selection port upon, whether the process was a Port, shown schematically in Fig. of either modem (0) or printer (1). All standard rates from 300 to 9,600 baud are selectable with appropriate CPU LED INDICATORS position of JP2. POCK Shown schematically in Fig. 3(C) is OCO..7] W C0..7J the circuitry for the Parallel Printer Port. Each data byte sent to the printer or, in this case, the Program- PRINTER PORT mer, is signaled by DST strobing low, l6K which sets the flip -flop made up of t;1 U12C and U12D. This sets the BUSY ' 000..77 line and latches the new data byte in- to U11. The 68701 microcomputer chip in Fig. 2 monitors the BUSY line $ ERIAL PORT P1O. When it detects activity on this ECK (P17). P16 P17 dr10 line, it reads the new data byte from P22 U11 in Fig. 3(C). P23 23 P24 iF2224 After processing the new data ECK- -ERST byte, U8 strobes ACK (acknowledge) at P16 low. The rising edge of ACK clears the U12C/U12D flip -flop, which clears the BUSY line to allow the host computer to send the next data byte. The only power required by the Programmer is 5 volts dc at 500 milliamperes. The + 21 volts (Vpp) needed to program the EPROM is supplied by the Dc -to -Dc Converter circuit shown schematically in Fig. 4(A). Fig. 1. Overall block diagram of the elements that make up the Programmer. Trimmer potentiometer R10 permits

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 25 adjustment of Vp, to the required that accompanies Fig. 4(A). Switch- fairly often. Therefore, since most + 12 -volt level needed for pro- ing of Vpp is accomplished with the cir- hobbyists and experimenters will al- gramming. This + 21 volts is applied cuit shown schematically in Fig 4(B). ready have on hand a suitable regu- to RESET pin 6 of U8 only when the The Programmer does not feature lated 5 -volt dc bench supply, this can internal EPROM is being pro- its own ac- operated 5 -volt dc power be used when needed. If you do not grammed. Power is distributed to the supply. While it is a valuable tool, the already have such a supply, or wish various ICs that make up the pro- Programmer is not the type of proj- to make the project self- contained, grammer as specified in the Table ect that you will use every day or even you can build any of a number of such supplies from the projects presented in Modern Electronics and other periodicals and books. You can even use a plug -in wall -type 5 -volt supply that is capable of delivering ti 500 milliamperes or more of current. a O-aNMOU0A O O.NMON0P 00000000 00000000 Construction O-N O.N O-NMONOA ..... 0-.NMO001,00--- fairly large V QQQQQQQQQQQQQ QQQQQQQQQQQQQ As you can see from the number of schematic diagrams pre- is a 1,. sented here, the Programmer fairly complex piece of hardware. The large number of interconnec- tions makes point -to -point wiring a task that should be performed only if you are an experienced project builder who is comfortable with the Wire Wrap technique. Otherwise, it is NMON 000 strongly recommended that you pur- a ready -to -wire printed- circuit .NMV001,0 V chase 00000000 VO board from the source given in the Note at the end of the Parts List. HiI If you are an experienced project builder and have confidence in your abilities to successfully wire together such a complex circuit, you can do so 1111111 1111111 using perforated board that has holes ., ..,. on 0.1 -inch centers and suitable Wire M-iIFIIII MIMI Í Wrap hardware. But work very care- Wrri ii iii i fully, and strike off each conductor 01 0.040,041, 0.NMf00. .N W Whichever method of construc- V V O Ñ N n it is idea to use m tion you use, a good sockets for all DIP ICs and a ZIF W - 0.0 0.NMO001, O.NMO (zero- insertion - force) socket for U8. X WKM .1.q.1..,MA NNNNN W :}MáM ao o.o.o.o.o. 0.40.0.0. Home fabrication of the double - a V sided printed- circuit board for the project is not recommended as practical because of the need for plating -

11111 through the holes that interconnect conductors located on both sides of the board. The ready -to -wire pc Wiil; ! ; V-h board from the kit supplier has plated- through holes and is silk - Fig. 2. Schematic diagram of the Processor and Memory sections. screened on the component side for

It In Electronics 26 / MODERN ELECTRONICS / May 1990 Say You Saw Modern Mount power terminal strip JI, Table 2. Serial Port Connector Pinouts DB -9S serial connector J2 and paral- Pin Circuit Description Direction lel printer connector J3 in their respective locations. Then mount and

1 CF Carrier Detect (DCD) From Programmer solder into place trimmer potentio- ' BB Receive Data (RD) From Programmer meter RIO. Finally, mount suffici- BA Transmit Data (TD) To Programmer ently long "legs" at the four corners 4 CD Data Terminal Ready (DTR) No Connection of the circuit -board assembly for the AB Signal Ground (SG) N.A. components mounted on it to clear 6 CC Data Set Ready (DSR) From Programmer whatever surface upon which the 7 CA Request To Send (RTS) To Programmer project sits. Use suitable length spac- R CB Clear To Send (CTS) From Programmer legs. y CE Ring Indicator (RI) No Connection ers and machine screws for the Alternatively, you can build a wood- en frame of sufficient depth in which to mount the Programmer to accom- easy component installation. Once the sockets are mounted in plish the same ends. Assuming you are using the pc place, proceed with installation of board, start wiring it by installing the the resistors, capacitors, crystal and sockets for the ICs. If you go the jumper pins. Make certain that the Initial Checkout Wire Wrap route, arrange and orient electrolytic capacitors are properly the components as near to the layout polarized before soldering their leads The only instrument you need to shown in the photo at the beginning into place. Continue wiring the check out the Programmer is a dc of this article. Whichever method of board with installation of the LEDs voltmeter or a multimeter set to the construction you use, however, do and transistors. Again, make certain dc -volts function. Clip the common not plug the ICs into the sockets until that the LEDs are properly oriented lead of the meter to a suitable circuit after you have conducted preliminary and the leads of the transistors go in- ground point, such as pin 2 of JI. voltage checks and are satisfied that to the proper holes before soldering With no ICs installed in the sockets, the project has been properly wired. any pins into place. apply + 5 volts dc to the Programmer

PARTS LIST Semiconductors C4- 680-pF ceramic disc J2 -Pc -mount DB -9S serial D -type D 1,D2 -1 N5819 diode C8 thru C12- 10 -µF, 16 -volt radial - connector LEDI thru LED4 -Green light -emit- ead electrolytic J3 -Pc -mount 36 -pin parallel printer ting diode C 13,C 14 -20 -pF ceramic disc connector LED5 thru LED7 -Red light- emitting C15- 0.01 -µF ceramic disc JP1- Single jumper assembly diode Resistors (% -watt, 5% tolerance) JP2 -6 x 2 jumper assembly QI,Q2- 2N3904 silicon npn transistor R1 thru R4-1,500 ohms Y1-2.4576-MHz solder -mount crystal Q3- 2N3906 silicon pnp transistor R5,R6 -6,800 ohms in HC -18 case U 1 -74HC 14 R7,R 11- 100,000 ohms Printed -circuit board or perforated U2 -78S40 R9 -130 ohms board with holes on 0.1 -inch centers U3- HC4040 R12 -4,700 ohms and suitable Wire Wrap hardware (see U4- MAX232 R13-0.62 ohm text); sockets for all ICs except ZIF U5 -6264 R14,R15 -1,100 ohms socket for U8 (see text); 5 -volt, 500 - U6 -2764 64K EPROM R 16 -100 ohms mA dc power supply (see text); solder; U7- 74LS138 R8 -270 ohms, 'A-watt etc. U8- MC68701 single-chip micro R 10-1,000-ohm, %-inch pc -mount Note: A minimal EP701 Programmer kit con- computer trimmer potentiometer taining a silk -screened double-sided pc U9- 74HCT573 RN1,RN3,RN4- 4,700 -ohm eight -pin board with plated-through holes and solder mask; programmed 2764 EPROM; and U10 ,U 11-74LS374 SIP resistor network with pin 1 in IBM for- U 12- 74LS00 common documentation diskette 360K mat is available for from Lucid Inc., Capacitors RN2- 220 -ohm eight -pin SIP resistor $35 P.O. Box 292, Mary Esther, FL 32569. Ro- CI ,C2,C5,C6,C7- 0.1 -µF ceramic disc network with pin 1 common rida residents, please add state sales tax. All C3 -22µF, 50 -volt radial -lead elec- Miscellaneous other components are available from local trolytic J1- Two -position power terminal strip suppliers and mail -order houses.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 27 RN2 220

VccO O F DCD__7] K c A A E I R Y Ñ L ó

ERASED Mrr LEDI 00 DO 01 Dl 02 D2 03 03 04 04 LED2 LEDE OS DS rr urr 06 D6 LOAD 07 D7 O CL 74L S3' LEDOrr PROGRAM '

LEDO LEDI VERIFY urr urr

(A)

VCCO CAPO :ITORS ON THIS PAGE ARE 10uFd AT 16V. ALL 1 c11+^ C12 R14 S RIS C9 U4 Cl. 2T 1.1k S 1.1k 3 Cl C2+ C10 V J2 C2 DCD D5R O 11 TIT TIO 14 RD 10 T2I T20 7 C7S

12 R10 R1I 13 R7S R20 R2I TO MAX232

614400 H

U3 li01 CLKar---- JP2 02 76800 03 RST il 1 12 04 C 2 11 OS C 3 10 06 C 4 9 07 L'ira-103_1 08 rCC 6 87 9600 09 JP1 JUMPER 6 %2 010 4800 011

0 = SHORTED = MODEM 1 = OPEN = PRINTER 68701 Bud Clock Pin P22 B t 76800 9600 38400 4800 19200 2400 9600 1200 4800 600 (B) 2400 300

It In Electronics 28 / MODERN ELECTRONICS / May 1990 Say You Saw Modern J3 CENTRONICS PARALLEL INPUT

..1..1,... U11 M DO 00 D1 01 02 02 03 03 D4 04 DS 0S D6 06 D7 07 OC VCC 9\ CLK

RN3 4.7k RN4

w--simmum u ACK\ 74LSOO 13 w!! 74NC 14 U lr . 7k V 5 U 1 D 6Q 74L 5OO R 16 U12C 9 t 100~ U12B C15 74L5OO 74NC-4 T .O1

BUSY\ U12D X DST\ 12 III74L500

(C)

Fig. 3. Schematic details of the Programmer's (A) LED indicator, (B) Serial Port and (C) Parallel Port circuits.

via JI, making certain that the power cate any solder bridges, particularly jumps between 20.8 and 21.2 volts. source is properly polarized. between the closely spaced pads for This is caused by the slow switching With power applied to the project, the IC sockets, clear it with desolder- speed of U2. When the 68701 that touch the "hot" probe of the meter ing braid or a vacuum -type desolder- will be plugged into the U8 socket is to each of the Vcc socket pins indi- ing tool. Do not proceed until you not programming its EPROM, there cated for UI through U12 in the table have rectified the problem. is very little current drawn; so the accompanying Fig. 4(A). In all cases, Once you are certain that the proj- slow switching speed will effortlessly you should obtain a reading of ap- ect is properly wired, plug the 78S40 keep up with the demand. proximately + 5 volts. into the U2 socket. Make certain that Now use the "hot" probe to mea- If you fail to obtain the proper the chip is properly oriented and that sure the potential at RESET pin 6 of reading at any one or more points in no pins overhang the socket or fold the U8 socket. Your reading should the circuit, power down the Pro- under between IC and socket. (This be about +4.9 volts. If it is 21 volts grammer and rectify the problem. applies for all IC installations.) Re- or so, there is a problem with the Check to make sure that all compo- apply 5 volts dc to the project. circuitry around Ql and D3; if near nents are in the correct locations and With the common lead of the me- ground potential, the problem is in that all are properly oriented and ter still connected to circuit ground, the Q2 circuitry. Whatever the case, based. Check to make sure that all touch the "hot" probe to pin 1 of U2, if a problem exists, power down the components are soldered into place. and adjust the setting of trimmer project and rectify the problem. Solder any connection you might control R 10 for a reading of + 21 Once you obtain the proper read- have missed and reflow the solder on volts. If you are using a digital meter, ings at all specified points in the cir- any suspicious connection. If you lo- you may notice that the reading cuit, power down the Programmer,

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 31 remove the meter from the circuit - A 68701 Assembly- Language Programming xample board assembly and allow the charges to bleed off the electrolytic capacitors. Then plug the ICs into A good way to show you how to use the create an environment that uses fami- directives their respective sockets. Install an Programmer described in the main arti- liar names. However, equate is to step you through a sample as- generate no executable code. erased 68701 in the U8 ZIF socket. cle sembly- language program. Such a pro- The next directive you come to in Note: Whenever you install or re- gram is that provided in Listing 1. Com- Listing 1 is ORG, or "originate." This move the 68701, make absolutely cer- ments, like the first line of the program, directive tells the assembler where code tain that you first disable power to begin with an asterisk (). The next should be placed in memory. In Listing the circuit! Otherwise, you run the eight lines in the program are examples I, the code would be assembled to start risk of permanently damaging the of the EQU, or "equate," directive, at location F800, which is the bottom of microcomputer chip. which allows you to assign a name to a the internal EPROM for a standard Place a jumper on the JPI pins. numerical value. After this, you can use 68701 microcomputer chip. Then place another jumper on the the name instead of the value, which Executable code is divided into two makes the program easier to read. For parts. These are an initialization section JP2 pins for the baud rate you wish to example, consider the following two that begins at the label RESET and a use. Turn on power to the Program- main program that begins with the label except lines of code: mer and note that all LEDs, LOOP. the OKAY one for the ERASE func- P1DDR EQU 00 Initialization begins by disabling all on for about a second and CLR PIDDR tion, come maskable interrupts. It then sets the then extinguish. The first line assigns the name stack pointer to address 00FF, which is

"PIDDR" (Port 1 Data Direction Reg- the top of the RAM internal to the Using the Programmer ister) to the value zero. The second line 68701. Next, it clears the Port 1 Data clears the data at address P1DDR -in Direction Register at address 0G. Ac- Your Programmer is now ready to be this case, address 00. The same thing cumulator A is loaded with the value put into operation. To operate it, con- can be done with CLR 00, but using the FF. Note that this instruction uses im- nect the Programmer to your com- name PIDDR gives clearer meaning to mediate addressing (#); so the Accumu- puter via either its Serial or Parallel the intent of the code. lator is loaded with the literal value FF, Port, using the appropriate cable. In Equate directives are valuable pro- not the data stored at address FF. Final- Port 3 the case of the Parallel Port connec- gramming tools in that they help you to ly, Accumulator A is stored at tion, you simply unplug the cable from your printer and plug it into Pa- Listing 1. Assembly Language Source Code rallel Port connector J3. *EXAMPLE ASSEMBLY LANGUAGE PROGRAM FOR THE 68701 If you are using the Serial Port P1DDR EQU $00 *PORT 1 DATA DIRECTION REGISTER arrangement, bear in mind that the P2DDR EQU $01 *PORT 2 DATA DIRECTION REGISTER P1DAT EQU $02 *PORT 1 DATA REGISTER Programmer is designed to operate P2DAT EQU $03 *PORT 2 DATA REGISTER as a DCE device. It uses a nine -pin P3DDR EQU $04 *PORT 3 DATA DIRECTION REGISTER P4DDR EQU $05 *PORT 4 DATA DIRECTION REGISTER female -type D connector that is di- P3DAT EQU $06 *PORT 3 DATA REGISTER rectly compatible with nine -pin P4DAT EQU $07 *PORT 4 DATA REGISTER COMM ports on most IBM PCs and ORG $F800 *START OF INTERNAL EPROM RESET SEI *DISABLE MASKABLE INTERRUPTS compatibles. The pin assignments LDS N$OOFF *INITIALIZE STACK POINTER and signal directions for Serial Port CLR P1DDR *MAKE PORT 1 LINES ALL INPUT in LDAA p$FF connector J2 are enumerated Ta- STAA P3DDR *MAKE PORT 3 LINES ALL OUTPUT ble 2. I f your modem or serial printer STAA P4DDR *MAKE PORT 4 LINES ALL OUTPUT LOOP LDAA P1DAT *READ THE DATA AT PORT 1 uses a 25 -pin D connector, you must STAA P3DAT *SEND IT OUT ON PORT 3 make an adapter cable to use the Pro- COMA *COMPLEMENT IT STAA P4DAT *PUT THE COMPLEMFNT OUT ON PORT 4 grammer with it. Be sure when mak- JMP LOOP *GO BACK AND DO IT AGAIN ing this cable that you check the defi- *INTERRUPT VECTORS ORG $FFFO nitions of the lines on your computer FDB RESET *SERIAL COMM match them with the correct lines FDB RESET *TIMER OVERFLOW and FDB RESET *OUTPUT COMPARE of the Programmer. FDB RESET *INPUT CAPTURE FDB RESET *EXTERNAL INTERRUPT You can operate your Program- FDB RESET *SOFTWARE INTERRUPT mer in either of two modes. If jumper FDB RESET *NONMASKABLE INTERRUPT RESET *RESET JP/ in Fig. 3(B) is not bridging (shor- FDB ting together) the two contacts

32 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics shown, the Programmer acts as a printer. On the other hand, if the jumper is present, the Programmer Listing 2. Assembler Listing operates as a modem. 0001 *EXAMPLE ASSEMBLY LANGUAGE PROGRAM FOR THE 68701 In Printer mode, the Programmer 0002 0000 P1DDR EQU $00 *PORT 1 DATA DIRECTION REGISTER monitors the Parallel and Serial 0003 0001 P2DDR EQU $01 *PORT 2 DATA DIRECTION REGISTER 0004 0002 P1DAT EQU $02 *PORT 1 DATA REGISTER Ports and accepts data from which- 0005 0003 P2DAT ZQU $03 *PORT 2 DATA REGISTER is an as- 0006 0004 P3DDR EQU $04 *PORT 3 DATA DIRECTION REGISTER ever active. The sl9 output of 0007 0005 P4DDR EQU $05 *PORT 4 DATA DIRECTION REGISTER sembler can be sent to the Program- 0008 0006 P3DAT EQU $06 *PORT 3 DATA REGISTER is 0009 0007 P4DAT EQU $07 *PORT 4 DATA REGISTER mer just as though it a printer. For 0010 example, on an MS -DOS system, you 0011 f800 ORG $F800 *START OF INTERNAL EPROM 0012 f800 Of RESET SEI *DISABLE MASKABLE INTERRUPTS would simply connect the Program- 0013 f801 8e 00 ff LDS #$OOFF *INITIALIZE STACK POINTER mer in place of your printer and type 0014 f804 7f 00 00 CLR P1DDR *MAKE PORT 1 LINES ALL INPUT 0015 f807 86 ff LDAA I$FF the normal print command: PRINT 0016 f809 97 04 STAA P3DDR *MAKE PORT 3 LINES ALL OUTPUT (FILENAME).S19. 0017 f80b 97 05 STAA P4DDR *MAKE PORT 4 LINES ALL OUTPUT 0018 f80d 96 02 LOOP LDAA P1DAT *READ THE DATA AT PORT 1 In printer mode, the Programmer 0019 f8Of 97 06 STAA P3DAT *SEND IT OUT ON PORT 3 all 0020 f811 43 COMA *COMLPEMENT IT performs operations automatical- 0021 f812 97 07 STAA P4DAT *PUT THE COMPLEMENT OUT ON PORT 4 ly. The result of each step in the pro- 0022 f814 7e f8 Od JMP LOOP *GO BACK AND DO IT AGAIN 0023 *INTERRUPT VECTORS gramming process is indicated by the 0024 fff0 ORG $OFFFO appropriate LED on the circuit - 0025 fff0 f8 00 FDB RESET *SERIAL COMM 0026 fff2 f8 00 FDB RESET *TIMER OVERFLOW board assembly. If any step fails, the 0027 fff4 f8 00 FDB RESET *OUTPUT COMPARE appropriate red LED lights and the 0028 fff6 f8 00 FDB RESET *INPUT CAPTURE 0029 fff8 f8 00 FDB RESET *EXTERNAL INTERRUPT process ceases at that point. When 0030 fffa f8 00 FDB RESET *SOFTWARE INTERRUPT programming is successfully com- 0031 fffc f8 00 FDB RESET *NONMASKABLE INTERRUPT 0032 fffe f8 00 FDB RESET *RESET pleted, all four green LEDs will be lit. 0033 When power is first applied to the Programmer, all LEDs come on for a second to check their operation. The and Port 4 Data Direction Registers, bel RESET, which is address F800. program then checks the on -board which sets all bits of both ports to out- When power is applied to the 68701, a EPROM of the 68701 to determine if put status. reset interrupt is generated and the vec- it is completely erased. If so, the chip The main program begins by loading tor at FFFE is fetched. In this case, ad- is ready to be programmed, and the Accumulator A with the data from Port dress F800 will be fetched and the pro- green ERASE LED turns on. 1 and storing it at the Port 3 data regi- gram will begin to execute there. The in- The programmer now waits for ster. Since Port 3 is all outputs, data itialization code will run, followed by you to send it an object file via either written to its Data Register immediately main loop. will the The processor con- the Parallel or the Serial Port. The appears on the Port 3 pins of the 68701. tinuously read the data on Port 1, out- object file must be in the Motorola Next, Accumulator A is complemented put it on Port 3 and output its comple- and stored at the Port 4 Data Register. ment on Port 4. standard S19 format. Any assembler Finally, the program jumps back to When the source code is assembled, for the 6801/03 microprocessor will LOOP -the top of an infinite loop. using the freeware cross -assembler generate this type of output. The interrupt vectors are the last part from Motorola, two files are created. As the object file is sent to the Pro- of the listing. There are eight vectors, These are the Listing File given in List- grammer, it is converted to binary and each one is a 16 -bit address. The ing 2 and the 519 Output File given in format on the fly and is stored in the processor requires the vectors to be at Listing 3. The Listing File contains the RAM buffer. If an error occurs dur- the very top of the internal EPROM for address and bytes assembled for each ing conversion, such as a non -hex all modes of operation, except mode line of input, followed by the original character or bad checksum, the red zero. An FDB (Form Double Byte) di- source code. The S19 Output File is an LOAD FAIL LED turns on. rective places a 16 -bit value at the next ASCII representation of the binary file Once the object file is loaded, the two bytes in memory. For the example that will be programmed into the internal EPROM can be programmed. in Listing 1, all vectors are set to the la- EPROM on -board the 68701. Successful completion of the pro- step is indicated by an on Listing 3. Assembler S19 Output File gramming green PROGRAM OKAY S11AF8000F8E00FF7F000086FF97049705960297064397077EF80D7D LED. S113FFFOF800F800F800F800F800F800F800F8003D 59030000FC The last step in the procedure is to verify that the programmed EPROM

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 33 IC +V GND V« o U1 14 7 J1 1 U2 13 3 2 POWER U3 16 8 TERMINALS R13 0.62 U4 16 15 LI C4 U5 28 14 28 14 680p 100u U6 , R9 U7 16 8 130 U8 7,21 1 U9 20 10 U10 20 10 U2 U11 20 10 76540 U12 14 7

e 7 6 n

V C

R12 C6 C7 ..".".. 1 .1 4.7k P R10 1k

(A)

R1 U1C 1.Sk A 74NC 14 VCC R7 100k UlA 2 L O 74MC14

(B)

Fig. 4. Schematic details of the Programmer's (A) Dc -to -DC Converter and (B) Reset Control circuits.

34 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics Free Product Information Use the How do I get more data? tree Readers can obtain free information on into card. products advertised, as well as for some editorially mentioned products. Table 3. Modem Mode Menu Screen Simply circle the appropriate number printed below an advertisement onto (U)pload ASCII SI /S9 file to buffer the AE "Free Information Service" (P)rogram EPROM from buffer card bound into this issue. After filling in (V)erify EPROM against buffer your name and address, just mail the (X) Buffer display, ASCII hex postpaid card. Your request will be for- warded (Y) EPROM display, ASCII hex directly to the advertiser with a 9 mailing label prepared by our reader - service department. is the same as the object file loaded Amazing into the RAM buffer. If verification New Sonic `SUPER EAR'MICROPHONE'" is successful, the green VERIFY OKAY Lets You LED turns on. If the verify step fails, the red VERIFY FAIL LED turns on. HEAR A WHISPER In Modem mode, the jumper is Don t be fooled by "heanng present on JP] and uses only the Seri- devices" that look like to 100 ordinary radio units Sonic al Port. To use this option, your up feet away Super Ear is the only high technological unit of its computer must be loaded with a com- kind with truly mulb- dnecbonal capability that is munications program capable of 'used by surveillance experts around the worn Buy handling ASCII file transfers. the best' Modem mode allows you to inter- act with the Programmer via the The Same Style menu shown in Table 3. Bear in mind Used By Detectives, that this is not an automatic mode. You must tell the Programmer to And Secret Agents & Surveillance perform each step of the procedure. Listen! Experts - NOW AVAILABLE These steps normally are: FOR PRIVATE CITIZEN USE!

(1) Upload the ASCII S 1 /S9 file to the buffer; (2) Program the on -chip EPROM î .., from the buffer; _ ek ,,,,

s 4 (3) Verify the data contents of the -' ue, , w i '* _ , due' ¡lc ,3tspitte e cats, g cv°

EPROM by comparing them with the acre' socket' Makes ne gt' `r a °a armr,e,' ]etw "vu PLEASE 1107E This oevwe Is not winded for eavesdropping re- data file stored in the buffer. Canes ma Naomi for or ULTRA SENSITIVE. MOIS- cordugs of ponte beacons m schnea comersabons TURE-SEALED MICROPHONE Though Modem mode is not auto- AMPLIFIES SOUND UP TO Value THE MOST PORTABLE, SOUND- matic in its operation, it does give COMPACT GATHERING 50 DECIBELS lal 20001' QReetail SYSTEM EVER RELEASED FOR DUBLIC SALE' 47 ,v CAN BE USED HANG HELD you more interactive flexibility than Ultra- Serlsiöye 4" "Sh4in Microphone with Special Price volume controlled ampl OR ATTACHED TO BINOCU is possible in Printer mode. For ex- LARS AND TAPE RECORDER' Now Only COMES COMPLETE WITH ample, in Modem mode, if you pro- HIGH PERFORMANCE grammed the 68701 and you cannot ADJUSTABLE HEADPHONES! SrEREO OPERATES ON JUST 1 " hAt $1999 what it HEADPHONES remember program contains, BATTERY lincludedl can also te used *Ai your Monograph the Programmer lets you determine Credit Card Holders a ape p_ CSI what the contents are. With the Pro- Call Toll Free 1-800-874-33371 grammer, you can upload an object U.S. Consumer, Dept. BE -62 TISFACTION GUARANTEED - file and verify it against the pro- 2721 U S. 19 North, Suite 173, Palm Harbor, FL 34684 YES' Please rush me Idly 'SUPER EAR' MICROPHONE - r.eieee concerts A ove meelll...IenN .rIincatlM I grammed data in the EPROM to see mrn to aMeol. ee.rw, SYSTEMISI at only 519.99 each purs S2 75 postage 8 handling Enclosed is S. FL 8 MI res. add sales tu.

if both contain the same data. Charged :. VISA ,1 Mc I : AMEo 1 DINERS cu In Modem mode, the program will Card not automatically terminate if a step En) Date _ Sgnuture fails. Therefore, you can upload and NAME verify again and again until you lo- ADDRESS cate the correct file. mE CITY STATE ZIP

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 35 Project An Electronic Controller For Slide Projectors

Controls on and off of a projector only when a slide is needed and provides a fade -in /fade -out feature for smoother presentations

By David Pouting

The constant whine of the fan motor of a projector can be an irritating distraction to both narrator and audience during a slide presentation. The Electronic Controller project described here will alleviate this problem. Our Electronic Controller for Slide Projectors is a small device that turns on the projector only when a slide is needed and changes to the next slide before it switches itself off. Addi- tionally, it permits each slide to be faded in and out for a smoother, less jarring visual presentation. The project actually consists of two basic elements-a phase -controlled dimmer circuit for the fade -in /fade -out function and a switch -on /change- slide/ switch -off control circuit. The project does not require any modification of the projector itself and is relatively easy to build using readily available for the entire project precedes the current flows to switch the diodes components and materials. dimmer circuit. fully on. The fader circuit was designed Diode D3 isolates point A, the around the LM393 dual voltage com- junction of the three diodes, from the About the Circuit parator specified for IC2. This par- smoothed dc produced by the filter-

Shown in Fig. 1 is the schematic dia- ticular chip is designed to operate ing action of Cl, at point B, so that gram for the entire Controller cir- from a single -ended dc power supply. the potential at the IN terminal of cuitry. The fade -in /fade -out dimmer In Fig. 1, operation of the dimmer regulator ICI is approximately + 8 portion of the circuit is composed of circuit is as follows. The low- voltage volts. At the OUT terminal of ICI, both comparators in IC2, optical iso- ac output from power transformer point C, the potential is a regulated lator IC6, the last stage shown in Fig. TI is passed through rectifier diodes + 5 volts, which is further filtered by 2(A), and each stage's associated DI and D2, to emerge as half -wave C2 and distributed throughout the components. Note also that the 117 - pulsating dc. Resistor RI is included circuit as needed. volt ac -line- driven dc power supply in the circuit to assure that enough Resistor R2 and zener diode D4

36 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics + ioloaload ol a!qeo iopnpuoo an! j ICI -7805 fixed 5-volt regulator IC2 -LM393 dual comparator i 1Oquoo a ssaula6ug a IC3- CD4538B dual CMOS multivi- ó brator IC4,IC5,IC6- MOC3041 optical isolator Q1,Q3- IRF511 (or any) n- channel power MOSFET o Q2,Q4,Q5- SC150M or similar triac z o r o Ur- Capacitors N -AF, 10 -volt O CI- 1,000 electrolytic C2 -1 -µF, 50-volt tantalum 4,-0 o C3,C7- 0.1 -µF polyester m (!) C4- 0.01 -µF polyester C5- 0.0056 -µF polyester No U C6- 22 -µF, 10 -volt tantalum OU C8- 10 -µF, 16 -volt tantalum C9 -4 -µF, 16 -volt tantalum Resistors (1/4-watt, 5% tolerance) o ti R1- 15,000 ohms R2,R3- 10,000 ohms R4,R5- 100,000 ohms Y R6 -100 ohms Q R7,R10,R12 -56 ohms

R8,R 1 I ,R 13 -270 ohms R9- 150,000 ohms R14 -1,000 -ohm multi -turn trimmer N potentiometer J R15- 100,000 -ohm linear -taper slide - or rotary-type potentiometer (see text) R16- 1- megohm trimmer potentiometer O Miscellaneous S1 -Spst lever or slide switch

U - momentary - N lL S2,S3- Normally -open, U ? action spst pushbutton switch SOI -Chassis-mount three -contact ac

N receptacle ° T1 -6.3 -volt center -tapped, 100-mA minimum power transformer a ,Qcv oV or perforated Printed- circuit boards with holes on 0.1 " and suitable LL board a aa rn u_ o CV _ Wire Wrap or soldering hardware (see U U N -vÚ U v ó -i text); sockets for all DIP ICs and op- o VV tical isolators; remote cable assembly (see Note below); suitable enclosure(s); ac line cord with plug; rubber o N 0 * co LL grommets; small- diameter heat - á U ó shrinkable or other insulating tubing; heat sink (see text); spacers; machine linoi!o hardware; hookup wire; solder; etc. lno-apej o o o o Note: The special seven -pin molded plug and u!-apej z W t!nono ..NO.. iotoaloid t!noi!o aouego aP!IS s 36" of five- conductor cable required for the remote cable assembly can be ordered as Part No. 215420 from Kodak Parts Ser- PARTS LIST D5,D6,D7- 1N4148 or similar switch- vice Dept. (716- 724 -7278) for $15. Alter- Semiconductors ing diode natively, see text for details. One source D1,D2,D3- 1N4001 or similar 50 -PIV, LEDI,LED2,LED3- T -l3/4 light -emit- for SC150M triacs is All Electronics (800- 1- ampere rectifier diode ting diode (one each red, yellow, 826- 5432), which also sources many of the D4 -6.2 -volt, 0.4 -watt zener diode green) other components specified here.

Fig. 1. Schematic diagram of basic Controller circuit.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 37 potential that can be varied from THICK RED 5V about 2 volts to 0 volt by R15, and a R12 sawtooth voltage of the same ampli- 56 MT2 _ tude. With RIS set at mid -position, 05 T7 .y the superimposed inputs are as SC150M 10 Ch / IC6 3 O)C shown in Fig. 4. MOC3041 aa 4) When the voltage set by RIS rises C N I? THICK BLUE to an amplitude that is just slightly FROM LED I > > A Y > THICK GREEN D N greater than that of the sawtooth am- FORWARD (FORWARD) 0 plitude, the pulses disappear and the YELLOW (COMMON) 2 COMMON » output at pin 1 of IC2B is always WHITE (REVERSE) high. Conversely, when the voltage REVERSE » set by RIS has an amplitude that is less than that of the sawtooth, the 2: (Thick green) 1 and 4: Remote focusing (not used in this project) pulses again disappear but, this time, Slide advance '! s leave the output continuously low. 3 3: (White) Slide When the output at pin 1 of IC2B is tray reverse 5: Common, yellow) Connected to Pin 2 to advance zero, both LEDI, which is in the cir- slide; connect to Pin 3 to reverse slide cuit to give an indication of the lamp tray by one brightness in the projector, and the Live in LLive out LED inside optical isolator IC6 (see (Thick red) (Thick blue) Fig. 2) will always be lit. With the Join together to connect switch lamp on when G LED inside IC6 on, the internal triac projector switch is in the "fan only position Mil MT2 is triggered into conduction and, in (B) FRONT (PIN) VIEW SC150M turn, drives external triac Q5 into full conduction. Fig. 2. Schematic diagram and wiring instructions for small junction box. As RIS is adjusted toward its alter- nate stop position, pulses synchron- ized with the 60 -Hz ac line will be regulate the pulsating dc from point point, the internal transistor in the generated. Both LEDI and the LED A and make it independent of any output stage of this comparator internal to IC6 are briefly switched but very large variations in the ac in- switches into conduction and dis- off during each half cycle, as are the put to the circuit. charges C3, with the resulting wave- internal and external triacs. As a re- Shown in Fig. 3(A) is the waveform shown in Fig. 3(C). sult, the projector lamp will not be form that appears at noninverting The straight vertical portions of receive full 117 -volt ac line voltage all ( + ) input pin 5 of IC2A. This com- the waveform shown in Fig. 3(C) are the time. The lamp will be dimmed parator stage has an open- collector the result of the output transistor in- progressively as RIS is adjusted to- output, which means that until the side IC2A switching on and discharg- ward its far end of travel. inputs at pins 5 and 6 are the same, ing C3. The curved portions have the Capacitor C4 filters out any noise the output at pin 7 of IC2A is effec- almost ideal waveshape cited above that might be picked up by the leads tively an open switch. to allow the lamp in the projector to from RIS from entering IC2B via + Initially, C3 is charged through R5 begin lighting without wasting the input pin 3. This capacitor should be and D5 by the waveform at point D, low end of main FADER control RIS placed as close as possible to the pin 3 shown in Fig. 3(B). This is clearly a and to speed toward full brightness at input during assembly of the circuit. very nonlinear charging current, but the high end of the control, while be- All of the above assumes that the it does produce an almost ideal wave- ing linear in the middle of the con- 117 -volt ac line power to the projec- form at pin 7 of IC2A. trol's range. tor is on but, at the beginning of the The voltage divider made up of R3 Potentiometer controls R14 and process, the projector is off and wait- and R4 ensures that the inverting ( -) RIS make up a pair of voltage divid- ing for the command to show the first input at pin 6 of IC2A is held just ers. Adjusting R14 assures that at slide in the cannister or tray. above 0 volt. When the pulsating dc one end of this main FADER control It would be an easy procedure for input at pin 5 returns almost to 0 volt R15, the lamp in the projector is fully you to turn on the projector and then at the end of each half cycle, both in- off. Hence, the inputs going to pins 2 fade in the lamp. However, it is more puts of IC2A become equal. At this and 3 of IC2B are, respectively, a set convenient if starting to move the

38 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics fade up is the way to switch on the the triac internal to IC4 switches on position. Only then will C8 recharge projector. This is accomplished in and drives external triac Q2 into con- through R16. As the potential across this Controller by the Fig. 1 circuitry duction. The result is that 117 -volt ac C8 rises through the input threshold made up of IC3A, Q1, IC4 and Q2 line power is applied to the projector of IC3B, the output pulse begins. The and their associated components. through ac receptacle SO/. slight delay before the output pulse One -half of a CD4538B dual mon- Of course, at this stage, you do not goes high allows the projector lamp ostable multivibrator, shown as want the timer to time out and switch to be completely out so that changing IC3A, is used here as the controlling off the projector until the projection of the slide will not be seen on- screen. element of the circuit for switching lamp has been faded up, the first Use of optical isolator IC5 and tri- on the projector. Assume that the slide has been viewed, the lamp has ac Q4 permits the slide- forward /re- projector is off and FADER control fully faded down and the change verse connections in the projector to R15 is set so that the lamp would be mechanism has advanced to the next be made without having to use a re- off if the projector were switched on. slide. Early timing out is prevented lay. The slide- change mechanism ad- Under these conditions, the output by D6. The first pulse comes in, trig- vances the slide tray by one.

from pin 1 of IC2B would be high. gers the onset of the output pulse and In summary, as the fader is first As soon as the fader starts to move C6 starts to charge through trimmer operated, the projector switches on up, however, a series of initially nar- potentiometer R16. However, each and the lamp is brightened to full. row pulses are initiated, the first of succeeding incoming pulse short -cir- When the slide is no longer required, which can be used to trigger IC3A. cuits C6 via D6, and so discharges the the fader completely fades out the When this stage is triggered, its out- capacitor. lamp in the projector, at which time put at pin 10 goes high. This causes When the lamp is fully on, pin 1 of the slide changes and the projector Q1 to switch into conduction, in turn IC2B is low. Hence, C6 will not switches itself off. causing the LED inside optical isola- charge at all. This capacitor will be Spurious spikes are prevented tor IC4 to light. When this occurs, permitted to charge fully only when from falsely triggering IC3A by R6 R15 has been returned to its fully and CS in the projector switch -on cir- faded -out position and all incoming cuit. Decoupling by C7 helps in pre- pulses have ceased. Only then can the venting similar false triggering. This timed output pulse really begin. Pro- latter capacitor should be placed as JAbout vided is near as possible to pins 8 and 16 8.5V this pulse long enough in dur- of ation to permit a third part of the cir- IC3A during construction. cuit to change the slide (this time in- Slide or toggle switch SI and push- (A) terval can be adjusted by setting button switches S2 and S3 permit you R16), the desired purpose is achieved. to manually set up and operate the The remainder of the circuit, built system. As mentioned above, LED1 around the second multivibrator gives an indication of the brightness \ 62 stage inside the CD4538 and shown of the lamp in the projector. Power as IC3B in Fig. 1, is used to change to the projector is visually indicated (B) the slide before the projector finally by LED2 lighting, while a slide switches off. Initially, with the pro- change is indicated by LED3. jector off, the output at pin 6 of IC3B A lightweight five -conductor cable is low while the input at D7 is high. of reasonable length (up to 100 yards 7. About 2V With the first negative -going pulse is possible with this Controller) oper- from pin 1 of IC2B at pin 4 of IC3B ates the projector from a remote } through D7, C8 immediately dis- point. By including optical isolator (C) charges through D7. Further pulses IC6, as shown in Fig. 2, close to the keep the capacitor discharged. With projector, this control cable does not Fig. 3. Waveforms that appear at IC3B configured so that it will trigger have to carry 117 -volt ac line power. various points in fade -in /fade -out only on a rising input, the output at Inserted in the cable close to the pro- circuitry: (A) pulsating dc with an pin 6 remains low and will not trigger jector, a small box serves as the junc- amplitude of about 8.5 volts at point to a high state until C8 is again per- tion that allows three of the cable's A; (B) truncated pulsating dc with an mitted to fully recharge. five conductors to join directly to the amplitude of 6.2 volts at point D; and Full recharging of C8 does not oc- common conductor (yellow insula- (C) waveform at pin 7 of IC2 of cur until the projector lamp fader has tion), forward thick conductor (green about 2 volts. been returned to its fully faded -out insulation) and reverse conductor

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 39 ated board, use the wiring guides Pin 1 switches from full on to full off at the crossing points. The output at IC2, shown in Fig. 7 as rough layouts for the components.) Voltage set When wiring the board, install and by R15 solder into place first the sockets for Output from the ICs and optical isolators. Do not IC1, Pin 7 plug the ICs into their respective sockets until you have conducted preliminary voltage checks and are certain that everything is okay. If you Output at Pin 1 - cannot locate six -pin sockets for the When the voltage set by R15 is raised: The output at IC2, Pin 1 is fully on for longer periods. optical isolators, carefully cut down Voltage set sockets with more pins or substitute by R15 Molex Soldercon® socket strips. With the sockets in place, install Output from and solder into place the resistors and IC2, Pin 7 trimmer controls, then the diodes and capacitors. Note that most resistors and diodes mount vertically on the board. Make certain that you Output at Pin 1 - properly orient any electrolytic capacitors and all diodes before soldering When the voltage set by R15 is lowered: The output at IC2, Pin 1 is fully on for shorter periods. leads into place. Output from their IC2, Pin 7 Next, install and solder into place regulator ICI and then the power Voltage set by R15 MOSFETs, followed by the triacs. Again, make absolutely certain that each of these devices is properly based before soldering any leads into place. Note that a number of components

Output at Pin 1 ' associated with the large main circuit -board assembly mount off the These include the power Fig. 4. Pulse waveforms at pin 1 of IC2 for various settings offader control R 15: board. (top) at mid- position; (center) near top of control; and (bottom) near bottom of transformer, all three switches, the control. three LEDs and slide potentiometer R15. To make connections to these components, you must install suit- (white insulation) of the projector's tions about isolating the 117 -volt ac able length wires at the indicated lo- molded plug and cable. from the low- voltage dc portions. cations. Make these wires about 4 in- The timing sequences for the com- Therefore, you can use printed -cir- ches long. Strip '/4 inch of insulation plete Controller circuit are shown in cuit boards on which to mount and from both ends of each. If you are us- Fig. 5. Figure 5(A) details the timing wire together the circuitry or perfor- ing stranded hookup wire, tightly for switching on the projector and ated board that has holes on 0.1 -inch twist together the fine wires at both fading the projector lamp to full centers and suitable Wire Wrap or ends of all wires and sparingly tin brightness. Figure 5(B) details the soldering hardware. Whichever way with solder. Then plug one end of timing for fading the projector lamp you go, be sure to use sockets for all each wire into the indicated hole and to full off, changing the slide and DIP ICs and optical isolators. solder into place. switching off the projector. If you wish to wire your circuitry Keep in mind that two copper con- on printed- circuit board, use the ac- ductors on the smaller junction -box tual -size etching- and -drilling guides pc board, both associated with triac Construction shown in Fig. 6. Then wire first the Q5, carry about 3 amperes of 117 - There is nothing critical about assem- main and then the smaller boards ex- volt ac line power. These are indicat- bling the Controller circuitry, other actly as shown in Fig. 7. (If you opt ed by extra -heavy traces in the small- than to observe the normal precau- for point -to -point wiring on perfor- er guide in Fig. 6. Strengthen these

40 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics traces by soldering along their Note: Instead of making direct ca- rubber -grommet -lined hole and tie a lengths thick pieces of heavy -duty ble connections to the circuit -board strain -relieving knot in it about 4 bare copper wire before installing assembly, you can mount a female inches from the end inside the enclo- and soldering triac Q5 into place. DIN -type five -pin connector in a sure. Separate the conductors a dis- You can use any enclosure you suitable hole in the enclosure and tance of about 1 1/2 inch and slip over wish to house the large circuit -board wire from it to the circuit -board as- each a 1 -inch length of small- diame- assembly. It must be large enough to sembly. Then terminate one end of ter heat -shrinkable tubing. Twist to- accommodate the assembly and pow- the control cable in a matching five - gether one line -cord conductor and er transformer and have enough pin male DIN -type connector, as il- one power transformer primary lead panel space on which to mount the lustrated in the cover photo. and solder the connection. Do the switches, control and LEDs. Ma- Tightly twist together the wires in same for the other line -cord conduc- chine the enclosure as needed (see each conductor of the ac line cord tor and transformer primary lead. lead photo for a suggested panel lay- and sparingly tin with solder. Pass Then slide the tubing over the con- out), including drilling the hole for this end of the line cord through its nections to completely insulate them entry of the five -conductor control cable. If you do not have the proper tool to make the long, narrow slot for Fader starts to close 1.-- Projector lamp fully out the slide control, substitute a rotary Inputs Into IC2 I Projector lamp starts to fade I bi.-- Fader fully closed control. Of course, doing this sacri- Pins 2 and 3 I i fices some of the "feel" for smooth I fades in and out. After machining the enclosure, deburr any holes drilled through metal Output IC2, Pin 7 jfffI to remove sharp edges. Line the ac line cord and control -cable entry holes with rubber grommets and Output IC3, Pin 10 mount the switches, slide (or rotary) Ti control and five -pin connector in Projector IC3 starts to tame out switches off their respective locations. Mount the - (about two seconds) power transformer with suitable Output IC3, Pin 6 hardware. Solder the transformer's About 72 second while -T2 During T2 the slide tray C8 charges about 1 second advances one position secondary leads in the appropriate while IC3B holes in the circuit -board assembly. (A) times out

Trim 1 ih inches of outer plastic jacket from the five -conductor cable I.- Fader starts to open Projector lamp fully ht and strip 3/4 inch of insulation from Inputs in o IC2 Projector lamp starts to fade up r Fader fully open Pins 2 and 3 r all conductors. Tightly twist together

the exposed wires of each conductor ,I and sparingly tin with solder. Pass this end of the cable through ! ,', ,, ,, its rubber -grommet-lined entry hole Output IC2, Pin 7 and secure a large plastic cable tie tightly around it about 4 inches from the end inside the enclosure to serve as a strain relief. Plug the conductors Output IC3, P 10 IC3A triggers but cannot yet start to ni, into the holes labeled +5V, FROM LEDI, SLIDE FORWARD, COMMON Projector off r_ Projector switches on and SLIDE REVERSE. Make a note on 11*- change a slip of paper of the color coding Output IC3, Pan 6 used for each conductor connection. (B) then mount the circuit -board assem bly with 1/2-inch spacers and 4 -40 x Fig. 5. Timing diagrams for (A) fading out lamp, changing slide and switching 3/4 -inch machine screws, lockwashers offprojector and (B) s witching on projector andfading up lamp. Waveforms are and nuts. not to scale.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 41 large plastic cable -tie strain relief and wire it to the small circuit -board assembly as detailed in Fig. 2. A less -expensive solution is to use two plugs, both available from your local Radio Shack store. Cat. No. 270 -041A is a round five -pin plug that fits into the top section of the socket on the projector, and Cat. No. 270 -017 is a multiple -pin plug that can be machined to fit a number of formats, including the two -pin format on the projector. If you go the less- expensive route, Fig. 6. Actual -size etching guides for (A) main and (B) junction -box circuits. you must fabricate the cable assembly yourself. This is simple enough to accomplish, using the details given in and shrink it into place. main circuit -board assembly) and Fig. 2 for wiring the cable to both the Next, wire the LEDs into the cir- solder each into place. circuit -board assembly and the con- cuit, making certain that you make The seven -pin molded plug and 36 nectors. the correct connections to the anode inches of seven -conductor cable re- Exercise care when fitting the and cathode leads. Insulate all con- quired for connection from the small small circuit -board assembly into its nections with heat -shrinkable or oth- branching box to the slide projector enclosure. If you use a plastic box for er plastic tubing. Then wire the can be obtained from Kodak (see the enclosure, make sure that no en- switches and slide (or rotary) control Note at end of Parts List). All you try /exit conductors on either side of into the circuit. need do to wire this into the circuit is the board can touch any others. Plug the LEDs into their respective to prepare its unfinished end as de- Also, fit a small heat sink onto the holes in the top panel of the enclo- scribed above for the control cable. triac on this board. Secure the board sure. If the LEDs do not remain in Pass this end into the enclosure to the enclosure via the hardware that place by friction, secure each with a through its grommet -lined hole, use a secures the heat sink into place. small daub of silicone adhesive or fast -setting epoxy cement.

Machining of the smaller junction R15

1 ON - rte- -01- 1 C:4 box in which the smaller circuit 71 R2 R5 - R1 D3 D4 -WIPER Secondary _D2_ KI C3 board assembly is to mount requires IC2 -OFF R14- m R3 Rd only three holes. One hole 1 05 drilling of C1 +SV E/CT K7 - is needed for mounting the circuit 0 K -LED1 board assembly inside the smaller en- S2- Reverse d5 Common LED2 -RSA 41- de I I closure. Then one hole is required for < IC4 817 K ` S3 entry of the control -cable from the t 1)6 B -Forward main unit and another for exit of the R17- Live On'- IC3 cable that goes to the projector. Af- -R16- I I R9 ter all holes are drilled, deburr them S1- L-- d6 edges and line the 0 to remove sharp Live r, In'- IK On Projector Socket LED3 cable holes with rubber grommets. TAB rThick 05 +5V Prepare the unfinished end of the 81ue IC6 R12 0 control cable as detailed above. Pass Thick á Red -R13- -LEDI the cable through its hole in the en- jD - Thick Slide closure and, again, use a large plastic Green Forward 3 E a - Common e Yellow cable tie to provide strain relief. Plug - LL LWhite- Slide the conductors into the appropriate - Reverse holes in the small circuit -board assembly (observe the same color coding used for the connections to the Fig. 7. Wiring diagrams for (A) main and (B) junction -box circuit boards.

42 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics If you use a metal enclosure for the junction -box assembly, make certain that the inside of the box is well -insulated from any part of the circuit - board assembly. The recommended triac on this board has an isolated metal tab that can be used to secure the circuit -board assembly into place. Additionally, the metal box will provide the required heat -sinking.

Checkout & Use Make sure no DIP IC or optical isolator is plugged into any socket on either board. Clip the common lead of a dc voltmeter or multimeter set to the dc-volts function to circuit ground. Plug the line cord of the Controller into a convenient ac outlet and touch the "hot" probe of the meter to pin 8 of the ICI socket and note the reading obtained. It should be +5 volts. If it is not, touch the "hot" probe to OUT pin 3 of IC/ and note if the reading is + 5 volts. If you still do not obtain a reading of + 5 volts, touch the "hot" probe to IN pin 1 of ICI. Now the reading should Small junction box plugs into connector on slide projector via a multiple-con- be approximately + 8 volts. ductor cable. This box must be located as near as possible to the projector but Switch your multimeter to the ac- can be tethered to main control unit via a cable up to 100 yards long. volts function. Touch the "hot" probe to the junction between R2 and D4. The meter should give a reading the ICs and optical isolators into vance to the next slide and switch off. of approximately 6 volts ac. their respective sockets. Make sure Adjust the setting of R16 until the If you fail to obtain the correct each is in its proper socket and is slide- advance process is completed reading at any of the points cited, properly oriented and that no pins before the projector switches off. unplug the project from the ac outlet overhang the sockets or fold under Leave the slide control in a position and correct the problem. Do not pro- between devices and sockets. that leaves the projector lamp just ceed until you do obtain the correct Set R16 and R17 to about mid -po- glowing dimly. reading at each point. sition. Plug the projector into an ac Adjust the setting of R14 to bright- Using the "hot" probe of the me- outlet, plug the cable coming from en the projector lamp, and move the ter, check the voltages at pins 3 and the small branching box into the pro- slide control until the lamp just glows

16 of the IC3 socket and pin 1 of the jector and plug the control cable into again. Repeat the process as many IC4, IC5 and IC6 sockets. In all the main unit. Plug the main unit into times as necessary until the slide con- cases, the correct reading is + 5 volts. an ac outlet. The projector fan may trol is at the "out" end of its travel. Failure to obtain the proper reading start operating and the lamp light Now adjust the setting of R14 to at any socket pin requires remedial (though not at full brightness) in the completely fade out the lamp, at work to rectify any wiring or compo- projector at this point. which time, the slide should change nent- installation error. Operate the slide control up and and then the projector switch off. Once you obtain the proper read- down to see if this action dims and If R14 is set too critically, switch- ings at all points cited, unplug the brightens the projector lamp. If it al- ing on an electrical appliance close to project from the ac line and discon- lows the lamp to go out completely, nect the meter from it. Carefully plug the projector mechanism should ad- (Continued on page 82)

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 43 Project

EXTErIDED

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The Extended Play Remote -Control System (Conclusion) Operating and construction details for the receiver module, system checkout and installation and use

7. Capacitor C6 and resistor R9 pro- This signal is then passed to the se- By Crady M. VonPawlak vide capacitive coupling of the signal ries- parallel bandpass filter made up impressed on the ac line by the trans- of C8, C9 and L1. The circuits thus passively Last month in Part I of this mitter to coupling transformer T2. far described extract and article, we discussed the This RC network plays a secondary amplify only those signals impressed theory of operation, con- role, attenuation of large power -line onto the ac power lines by the Ex- struction and initial checkout of the spikes and transients that can enter tended Play carrier -current transmit- transmitter portion of the Extended T2 or power transformer TI. ter while rejecting the majority of Play Remote -Control System. This The receive side of T2 (pins 5 and transients, noise and signals pro- month we conclude with the receiver 6) is impedance- matched to the ac duced by non -related, carrier -cur- module, system checkout and instal- power line. This impedance can vary rent devices. lation and use of the full system. The from 3 to 14 ohms. To accommodate After filtering and amplification, to cur- system enables one to control a VCR these variations, the receiver circuit the received signal is passed or stereo music system with his infra- has been optimized for a 3 -ohm rent- limiting resistor R4 and clipping red hand -held remote controls from worst -case operation. diodes CRI and CR2. The two diodes another location without running As the incoming signal is passed to limit signal amplitude to a normal- 1.4 volts, connecting wire or cables. Thus, one the secondary of T2 (pins 3 and 4), it ized level of approximately Reverse - can watch or listen on a set in another is stepped up by a turns -ratio of ap- as seen by transistor Ql. room while maintaining full control proximately 10:1. Capacitor C7 biased switching diode CR3 across nega- of the device in the main room. across this winding forms a high -Q CRI and CR2 clamps against LC resonant tank circuit that is designed for optimum operation in the About the Circuit frequency range of 30 kHz to 60 kHz, schematic diagram The complete schematic diagram of which is the anticipated frequency Fig. 8. Complete receiver module circuitry. the receiver circuitry is shown in Fig. range of the received signal. of

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Say Yoi. Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 45 tive -going transients that may enter through the bandpass filter stages. A variable -level voltage divider bias is provided for Ql by R3 and trimmer potentiometer R1. This circuit provides a simple method of adjusting overall receiver gain (sensitivity) for setting optimum performance for a given location within your home. Resistor R2 sets the collector current for transistor Ql. When the received control signal is passed to the base of Ql, a current flows through the emitter -collector junction of QI, which causes the collector voltage to appear as a ground (low) potential to the input of U2. Resistor R2 holds the input to one gate of U2 in a normally high state until a control signal is received. CMOS hex Schmitt -trigger inverter U2 cleans up the amplified signal 00 that appears at the collector of Ql. It board. also provides additional drive cur- Fig. 9. Actual-size etching -and-drilling guide for receiver printed- circuit rent to accommodate both the LED visual indicator and the IR driver final output stage. the hand- Visual indication of a received sig- complish this, the shared output of signal originally emitted by -control transmitter nal is provided by light- emitting di- U2 is passed to the IR output driver. held IR remote though it is at a ode D3. The output signal from U2 is This output is capacitively coupled used with the project, level. passed to current -limiting resistor R7 by C5. This ac coupling provides greatly increased energy dc power sup- to drive the base of switching transis- overdrive protection for Q3 and the A simple regulated circuit is provided tor Q2. This causes a current to flow power supply should the manual gain ply for the receiver UI. through the emitter -collector junc- be set high enough to force the out- by TI, BRI,C1,C3and tion of Q2 and forward- biases the put of U2 into a continually on dc) and /or should any LED. Current for D3 is provided by (steady state Construction R8 /C4. Capacitor C4 maintains a front -end component fail and cause a high current at the anode of D3 while the same effect as excessive current For the receiver, you can use either preventing excessive dropouts and drawn by the IR diodes. printed- circuit board or perforated -inch cen- spikes from appearing on the 8 -volt Voltage-divider bias of the signal is board that has holes on 0.1 or sol- dc power supply during the LED provided for Q3 by R5 and R6. The ters and suitable Wire Wrap to mount turn -on and turn -off cycles. required IR energy is generated by dering hardware on which These on /off cycles appear at the high- output IR-emitting diodes Dl and wire the components. If you opt wish to fabri- same rate and frequency as that of and D2. Buffer capacitor C2 main- for pc construction and the actual - the received signal. This indication tains the high current levels required cate your own board, use guide shown can be used in conjunction with the for proper operation by DI and D2 size etching -and drilling can pur- manual gain control to provide for a during reception and re- transmission. in Fig. 9. Alternatively, you from the quick visual reference of receiver When a positive -going signal is chase a ready-to -wire board Note at the end of gain setting during initial installation present at the base of Q3, a current source given in the of the receiver module. flows though the emitter -collector pn the Parts list. on, we will assume that To communicate with the device(s) junction of the transistor. This for- From here pc construction. This to be controlled, the received control ward- biases DI and D2. The rate and you are using case, refer to the wiring signal must be reconstructed and out- frequency at which Q3, DI and D2 being the in Fig. 10. (If you go the put in its original IR energy. To ac- operate exactly matches that of the guide shown

Say You Saw It In Modern Electronics 46 / MODERN ELECTRONICS / May 1990 make suitable adjustments in the templates before using them for ma-

03 chining the panels. R7 1 1 When machining of the panels is R6 complete, do not set the self -stick 02 D3 N C4 front -panel overlay in place. You R10 1 must first mount the front panel in C5 c R5 1 place on the enclosure, using the

U1 small screws provided, before at- tempting to mount the overlay, which then covers the entire panel, > 01 U R2 including the screw heads. There- ao Cl ó L1 C9 R4 fore, save installation of the front - U C7 C8 -- panel overlays on both the transmitter and receiver modules until after Ti R9 the entire system has been checked R3 out for proper operation. r Meanwhile, pass the unfinished Fs, -I R1 end of the ac line cord through its )HOT -F1- T2 1 hole in the rear panel and fasten it in GAIN ADJ. IN RECEIVER place with a plastic strain relief, or tie a strain -relieving knot in it about 3 inches from the unfinished end on Fig. 10. Wiring guide for receiver pc board. the inside of the panel. Tightly twist together the fine wires in each line-cord conductor and sparingly tin with solder. Plug the point -to -point wiring route, use Fig. Tl and that the notch on the case of conductors into the 120 VAC IN holes IO as a rough guide to component T2 is oriented along the heavy straight in the receiver circuit -board assembly placement.) line in the case outline for this corn- and solder into place. (Note: Check Use t:le same assembly procedure ponent in Fig. 10 before soldering which conductor you plugged into to wire the receiver board as detailed any leads or pins into place. the hole labeled NEUT in the trans- last month for the transmitter board. Install the three LEDs in their re- mitter board. Regardless of whether That is, start by installing and solder- spective locations on the edge of the its insulation is smooth or ribbed, ing into place the sockets for DIP circuit -board assembly as shown. plug the conductor with the same in- 1C2. Do not plug the IC into the sock- Note that if any LED overhangs the sulation in the NEUT hole in the re- et until after you have conducted a edge of the board, it should do so by ceiver board. voltage check and are certain that the no more than /16 inch, as illustrated in Now perform voltage checks to as- board has been properly wired. Fig. 11. Use a short length of No. 32 certain that the receiver module has Proceed with installation of the re- bare wire for fuse FI. been properly assembled. For this, sistors, capacitors and diodes. Make Machine the enclosure that will you need a dc voltmeter or a multi - sure the electrolytic capacitors and house the receiver module. This is meter set to the dc-volts function. diodes are properly oriented before done in basically the same manner Clip the common lead of the meter soldering their leads into place. Next, that was described last month for the to a convenient circuit -ground point install Cie transistors and then GAIN transmitter module, except that an on the receiver circuit -board assem- ADJUST trimmer RI in their respec- extra hole, to provide access to trim- bly, such as the metal tab on the tive locations. Again, make sure that mer GAIN ADJUST potentiometer RI bridge- rectifier assembly. When you the transistors are properly based be- is required in the rear panel. If you perform the following voltage tests, fore soldering their leads into place. are Lsing the type of enclosure sup- make absolutely certain that you do Now install power transformer Ti plied with the kit (see Parts List), use not touch the primary circuit of Tl. and coupling transformer T2 in their the actual -size machining templates Potentially lethal 117 -volt ac line po- respective locations. Make absolute- provided in Fig. 12 as guides for the tential is present in this portion of the ly certain that you do not transpose rear (A) and front (B) panels. If you circuitry. the primary and secondary leads of are using any other type of enclosure, When you are ready to perform the

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 47 MASTER PARTS LIST RECEIVER T1- 12.6 -volt ac, 300-mA pc -mount C11- 0.01 -µF, 100-volt metalized polyester Semiconductors power transformer C 12,C 13- 220-pF, 16 -volt monolithic -PIV bridge rectifier assembly T2- 100-µH coupling transformer BR1 -50 ceramic CRI,CR2,CR3- 1N4148 switching (TOKO No. 707VX- A03YUK) Resistors (%1 -watt, 5% tolerance) diode Printed-circuit board or perforated centers RI -100,000 ohms D1,D2 -LD271 IR- emitting diode in board with holes on 0.1 -inch Wrap or soldering R2- 39,000 ohms T1'/. package and suitable Wire socket for U2; R3 -6,200 ohms D3- Yellow light- emitting diode in hardware (see text); strain R4,R5 -1,000 ohms T1h package polarized ac power cord; plastic suitable R6 -330 ohms Q1- 2N2222A general -purpose npn relief (optional -see text); etc. R7-47 ohms, ''/ watt silicon transistor enclosure; hookup wire; solder; R8,R9-4.7 ohms, /: watt Q2,Q3-MPSA13 Darlington transistor Miscellaneous in TO -220 TRANSMITTER U1-7808 + 8 -volt regulator F1 -''h- ampere fuse (see text) Semiconductors package T1 -12.6 -volt ac, 300 -mA pc -mount BR1 -50 -PIV bridge rectifier assembly U2- CD4584BC CMOS Schmitt -Trig- power transformer CRI- 1N5819 Schottky diode gerinverter T2- Coupling transformer (TOKO D1- SFH2O5 photodiode Capacitors No. 707VX-A043YUK) D2 -T1% green light- emitting diode C 1- 1,000 -µF, 35 -volt electrolytic Printed- circuit board; suitable enclo- Q 1 -TIP 120 power Darlington transis- C2- 1,000µF, 16 -volt electrolytic sure (see text); ac line cord with plug; tor (TO -220 package) C3,C4,C5 -47µF, 16 -volt electrolytic sockets for U2 and U3; fine copper Q2- MPSA13 Darlington transistor C6- 1.0µF, 250 -volt metalized polyester mesh for Faraday shield (see text); U 1 -78L05 + 5 -volt regulator C7- 0.1µF, 50 -volt metalized polyester hookup wire; solder; etc. C8,C9- 0.033µF, 50 -volt metalized U2- CD4584BC CMOS hex Schmitt - polyester trigger inverter Note: The following items are available from infrared amplifier P.O. Box 2295, Ever- Resistors ('''h -watt, 5% tolerance) U3- TDA4060 Scientific Engines, Extended Play R2- 10,000 ohms with agc ett, WA 98203: Complete Capacitors transmitter and receiver kit (includes pc R3- 39,000 ohms compo- C1- 1,000 -µF, 35 -volt electrolytic boards, enclosures, all electronic R4,R7 -6200 ohms and self- adhering C2-47-AF, 50 -volt electrolytic nents, copper screen R5, R6 -1,000 ohms front -panel overlays), $119.95 plus $3.50 47 -µF, 16 -volt electrolytic R8 -150 ohms C3- P &H; additional receiver and transmitter C4-47-AF, 35 -volt electrolytic R9, R 10 -47 ohms, '/2 -watt kits, $62.95 each plus $2.50 P &H; ready - 4.7 -µF, 16 -volt electrolytic R1- 50,000 -ohm upright pc- mount, C5- to -wire transmitter and receiver pc boards, polyester noninductive trimmer potentiometer C6 -1 -µF, 250 -volt metalized $32.50 per set of two plus $2.50 P &H. Miscellaneous C7- 0.22 -µF, 16 -volt metalized polyester Mail orders, make payment via certified Fl-h-ampere fuse or No. 32 solid bare C8- 0.33 -µF, 16 -volt dipped tantalum check or postal money order; Visa/ call: (206) 348 -7754. wire (see text) C9- 0.1 -SF, 16 -volt metalized polyester MasterCard orders, 100-volt metalized Washington residents, please add state L 1- 470 -µH low -power inductor with C10-0. l -µF, sales tax to all orders. iron or ferrite core and axial leads polyester

installed. voltage test (U2 should not be in its probe of the meter to INPUT pin 1 of special basing are properly socket at this time) turn the thumb - regulator UI, where you should ob- Turn over the circuit -board assem- wheel of trimmer potentiometer RI tain a meter reading of approximately bly and check all soldering. If you fully counterclockwise, and place the +20 volts. If you fail to obtain the missed any connections, solder them circuit -board assembly on an insu- proper reading at either or both now. If any connection appears lated surface. points on the circuit -board assembly, grainy or otherwise suspicious, re- Plug the receiver's line cord into an unplug the receiver module from the flow the solder on it. Also, clear especially ac outlet and touch the "hot" probe ac line and carefully check over all away any solder bridges, pads for of the meter to pin 14 of the U2 sock- component installations and wiring between the closely- spaced with desolder- et. The meter should register a read- and soldering. Make sure each com- the U2 socket and T2 -type desolder- ing of + 8 volts. If you do not obtain ponent is in its appropriate location ing braid or a vacuum until you the proper reading, touch the "hot" and those that require polarizing and ing tool. Do not proceed

Say You Saw It In Modern Electronics 48 / MODERN ELECTRONICS / May 1990 have rectified the problem. er module across the room from your When you are satisfied that the cir- VCR so that its front -panel IR win- cuit -board assembly has been prop- RECEIVER PCB dow faces the front of the VCR at a erly wired, unplug it from the ac line. distance of not more than 18 feet. Allow the charges to bleed off the Plug the receiver's line cord into a electrolytic capacitors in the power convenient ac outlet. Use a small supply. Then install U2 in its socket. screwdriver to slowly adjust the GAIN Make sure the IC is properly oriented control through its access hole in the and that no pins overhang the socket 1/16 INCH rear panel clockwise until the LED MAX. or fold under between IC and socket. just begins to glow very brightly. Then back off (counterclockwise ro- RIGHT SIDE VIEW Operational Checkout tation) until the LED either suddenly goes dark or suddenly glows dimly. Place the transmitter and receiver when Fig. 11. Mounting details for the If the LED glows dimly even modules -to -back (all LEDs back on LEDs on the receiver pc- board. the GAIN control is adjusted fully (or both boards facing away from each nearly) counterclockwise, excessive other) on an insulated surface and noise is present on the ac line. You plug both units into ac outlets. Using the translucent red filter sections are may leave the unit plugged into this a VCR, TV or other IR remote -con- positioned over the rectangular cut- outlet or test others in the room for trol transmitter to activate the trans- outs in the panels. Slide the circuit - quieter operation. Alternatively, you mitter should cause the receiver board assemblies into their enclo- can make either or both of the fol- board to respond. This activity will sures and mount the rear panels in lowing modifications. be eviden. by the visible LED on that place, again with the supplied screws. In the transmitter module, replace module flashing when any transmit- Position the Extended Play receiv- C7 with a 0.1- microfarad polyester ter key is held down. Now place the Extended Play transmitter and receiver units so that they are face -to -face (all LEDs on both units facing each other). This should FA cause the system to self -oscillate I UP 5/16 DIA. from IR feedback. You may have to start the ball rolling with a little stim- ulus from your remote -control transmitter. A:though not recommended POWER CORD for more than a few seconds at a ENTRY GAIN ADJUST time, this test will easily show that ACCESS J everything is working as it should. When you are confident that both REAR PANEL TEMPLATE - RECEIVER units are performing satisfactorily, it is time for a test using the actual components the system will control. Al- though the following procedure can r- be accomplished with a CD player, I I UP stereo system or any other IR -controlled appliance, a VCR and some IR WINDOW CUTOUT 1/4 DIA. means of sending its output to a re- ED motely located TV receiver will be assumed. Of course, if you have any of 340R3ä these other devices, you can use one L J of them instead. FRONT Mount the front panels on the PANEL TEMPLATE - BOTH UNITS transmitter and receiver unit enclosures with the provided screws and Fig. 12. Machining templates for rear (A) and front (B) panels of receiver carefully install the overlays so that enclosure.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 49 or Mylar capacitor. This slightly reduces the threshold of the IR circuit but otherwise leaves unaffected the 18- foot -plus range of the project. In the receiver module, place a 1,000 - ohm resistor across (in parallel with) C7. This effectively lowers the Q of the LC tank circuit to reduce noise - induced "ringing." Neither of these modifications will noticeably reduce the performance of the circuits. Once you have set the receiver threshold, play a prerecorded video- cassette through the VCR. After pressing PLAY, check the remote TV receiver (it is assumed that you have run video and audio cables from the VCR to the remote TV receiver be- Fig. 13. Photo shows fully wired transmitter (left) and receiver (right) circuit - forehand) to be sure it is playing board assemblies just prior to installation in the enclosures atop which they sit. whatever is recorded on the tape. Place the Extended Play transmit- on or near the remote TV receiver. ter the scope you use has a three -prong magnetic radiation, or noise) than do the remote-control transmitter Using power -cord plug, use a three- to -two- TV receivers. If your remote TV re- with the VCR, press PAUSE supplied prong adapter between it and the ac ceiver is located close to a computer, (not being able to see the VCR indica- outlet before use. try to keep the Extended Play trans- used tor lights may take some getting mitter at least 24 inches from the remote -re- to if you have never used a System Installation computer monitor. Any interference mote control system before). If you from the computer monitor can be Extended Placement of the Extended Play correctly assembled the identified by continuous erratic mod- transmitter(s) and receiver in your Play transmitter and receiver flashing of the transmitter LED. ules and your house wiring provides home depends as much on room lay- pre- good coupling, the TV image dis- out as on personal taste. You can Some Caveats played on the TV receiver screen test different locations for the receiv- should freeze to a still picture. er using a hand -held remote -control When you are setting up the Ex- This simple test verifies that the transmitter to emulate the proposed tended Play or any carrier -current system is, indeed, operating as it positioning. If a given location works system for permanent use there are should. If you wish, you can resume well with the remote -control trans- several things to watch for. One is ca- picture action, stop it, fast forward mitter, it will almost certainly work ble TV converter -box IR remote con- or rewind to another section of the as well with the receiver. trol systems. Although the majority tape to check out these functions as As a matter of convenience, you of these systems are well designed, well. However, if even one function may want to experiment with placing some are poorly designed with regard works via the Extended Play link, all the receiver directly on top of or to method of IR transmission. A very other functions will as well. alongside your VCR. If a window or few converters (the type distributed If your VCR does not respond pro- light-colored wall directly faces the by some cable TV franchises) use an perly during the system operational VCR from across the room, the re- unmodulated IR signal to transmit check, something is wrong with the ceiver should be able to beam the the control codes. In affect, these wiring in either the transmitter or the control signals at the wall with enough systems simply use slow on /off receiver module or both. In this energy that they reflect back to the pulses that make them susceptible to event, power down both units and VCR without significant loss. false signals and may or may not be carefully check over your work. The transmitter can be placed be- accurately retransmitted by the Ex- If you have a problem and use an side or atop most TV receivers with- tended Play system. oscilloscope to perform any tests in out experiencing erratic behavior. High noise levels may appear on the Extended Play circuits, do not However, computer monitors pro- the ac power lines used to carry the make any connections to ground. If duce a great deal more emi (electro- Extended Play signals. Although this

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50 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics is not a significant problem, it ap- mended by several manufacturers of burglar alarm accessory, a remote pears at the receiver as a constant, carrier -current controllers in their in- appliance controller and more, as- dim glowing of the LED indicator. stallation manuals and troubleshoot- suming you come up with suitable in- You can tackle the problem by modi- ing glides. Although this should be terfaces. Add to this list lights, heat- fying the transmitter or /and receiver looked upon as a last resort (few ers, fans and air conditioners, all of as described above to deal with this homes actually need this modifica- which should be able to be controlled problem. tion), it will benefit any carrier -cur- with the proper interfaces. Even a A final consideration is the house rent accessories you presently own. personal computer with an IR trans- wiring itself. Because of the manner Now that you have established an mitter adapter is not inconceivable! in which the incoming 240 volts ac is IR link via the ac wiring in your With a bit of ingenuity on your part, divided into its two respective home, some interesting possibilities you can probably think up dozens of 117 -volt ac legs, it is possible for two are passible. For example, you can other control applications for the Ex- outlets in the same room to be on use the Extended Play system as a tended Play. IE completely different circuits, each 180 degrees out -of -phase with the other (with respect to neutral). This single anomaly in the house wiring is the biggest hurdle to be overcome by any carrier- current system. soBSCß Now In effect, for an ac outlet on one circuit to communicate with another on a different circuit using carrier - lit SAVEI current transmission requires that the signal make a round -trip via the step -down transformer located somewhere in your neighborhood. The solution for this is as simple as M O R T H A N placing a 0.01- microfarad high -voltage capacitor (rated at 400 volts or greater) directly across the 240 -volt ac line somewhere in your home. This capacitor can be installed at the outlet of any 240-volt ac appliance or at the breaker box (or fuse panel) where the 240 -volt line enters your home. A good choice for such a capacitor is the Radio Shack Cat. No. 272 -160. Rated at 2,000 volts (2 kV), it will easily handle permanent installation across a 240 -volt ac line. Surround Sound Processor by If you decide to install this capacitor, exercise extreme caution! Bear Heathkit Surround yourself with a vast assortment of kit or ready -to -use electronic products firmly in mind that 240 volts ac is from the FREE Heathkit Catalog. The Heathkit innovative home lethal. Therefore, before even at- Catalog contains tempting to make any connections, theater components, amateur radio and weather equipment, laptop computers, self - study electronics courses and challenging kits for the first -time builder. make sure to open the main breaker starter Order your FREE Heathkit Catalog NOW! (or remove the main fuse) at the junction box to shut down all power with- 1- 800 -44 -HEATH Send to: Heath Company, Dept. 079 -894 in your home so that you can work in (1- 800 -444 -3284) Benton Harbor, Michigan 49022 complete safety. As a further precau- I Name tion, check the "dead" house wiring with an ac voltmeter prior to touch- Ada resa ing any house wiring. C_ y State Zip This modification is recom- L A subsidiary of Zenith Electronics Corporation

CIRCLE NO. 151 ON FREE INFORMATION CARD

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 51 Technology Interfacing 555 Timers

A hands -on look at real -world use of this ubiquitous and very versatile IC timer chip

By Joseph J. Carr on the configuration of the external load. Figure 2 illustrates both types Ground 1 e V+ supply The 555 timer chip ranks as per- of operation. Trigger 2 7 Discharge haps the all -time most popu- 555 The arrangement shown in Fig. lar device in the IC arena - Output 3 6 ThreShold 2(A), in which external load RL is with good reason. Its immense popu- Reset 4 5 Control voltage connected between the 555 output larity derives from the fact that the and V + , allows current to flow in the 555 is inexpensive, well- behaved and load only when pin 3 is low. In this limit- is so utterly useful in an almost Fig. 1. Package configuration and condition, the external load is Since a less variety of applications. pinout details for the 555 timer. grounded through pin 1 and small in- lot has been written over the years ternal source resistance R51. In this about the 555, we will not begin at the arrangement, the 555 output is a cur- beginning here. We will assume that OUTPUT pin 3 abruptly switches to rent sink. you either already know the basics or the high state. The output remains The circuit shown in Fig. 2(B) is where to look for them. Instead, we high as long as pin 2 is low, but the for the case where the load is con- will concentrate in this article on in- output does not necessarily revert nected between pin 3 of the 555 and terfacing between the 555 device and back to low immediately after pin 2 is ground. When the output is low, the the "outside world." brought high once again. load current is zero. However, when OUTPUT (pin 3) is capable of either the output is high, the load is con- Definitions sinking or sourcing current up to 200 nected to V + through small internal is in to resistance R52 and pin 8. Here, the Shown in Fig. 1 are the package and milliamperes, which contrast pinout details for the popular eight - other IC devices in which the outputs output is a current source. pin mini -DIP version of the 555 either sink or source current, but not RESET (pin 4), when low, immedi- 555 at timer. In reviewing pin function defi- do both. Whether the 555 output op- ately switches the output of the nitions and their uses, keep in mind erates as a sink or a source depends pin 3 to a low state. In normal opera- that "high" means a potential that is greater than 2(V + )/3 and "low" means either a grounded condition, v+ V+ where V = 0 (as in the case of the RESET pin) or a potential that is less than (V + )/3 (as in the case of the TRIGGER pin). Pin function definitions for the 555 timer are as follows: R GROUND (pin 1) serves as the com- l ()AD mon reference point for all signals and voltages in the 555 circuit, both internal and external to the chip. TRIGGER (pin 2) is normally held at In a potential greater than 2(V + )/3. (A) this state, 555 OUTPUT pin 3 is low. If sink and (B) an output the TRIGGER pin is brought low to a Fig. 2. Examples of a 555 used as (A) an output current potential that is less than (V + )/3, current source.

52 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics tion, it is common practice to connect pin 4 to V + to prevent false re- sets from noise impulses. CONTROL VOLTAGE (pin 5) normally rests at a potential of 2(V + )/3 due to an internal resistive voltage divider. Applying an external voltage to this pin, or connecting a resistor to ground, changes the duty cycle of the output signal. If not used, pin 5 should be decoupled to ground through a 0.01- to 0.1- microfarad capacitor. THRESHOLD (pin 6) monitors the voltage across the capacitor in the ex- Fig. 3. Timing diagram (A) of a one -shot multivibrator built around the 555 ternal RC timing network. If pin 6 is timer and (B) details for assembling a 555 a one-shot multivibrator. at a potential of less than 2(V + )/3, the output (at pin 3) is high. Alterna- tively, when the voltage on pin 6 is stable multivibrator configuration of we will less than 2(V + )/3, the output is low. the 555 that use as the basis for our discussions here. s1 DISCHARGE (pin 7) is connected to N.O. R2 the collector of an internal npn tran- switch 10K sistor. The emitter of this transistor is Input Triggering connected to the ground (pin 1) of the The 555 MMV circuit triggers by (A) 1-43 555. When the 555 times out, the bringing pin 2 from a positive voltage transistor turns on and can discharge down to a potential of less than the external timing capacitor. (V + )/3. Triggering can be accom- V + POWER SUPPLY (pin 8) connects plished by applying a pulse from an R2 10K to the positive rail of the power sup- external signal source or through ply that drives the 555 timer chip (and other means. R3 1111 usually any other circuitry). Good Figure 4(A) is the schematic dia- 2.7K Q1 o- practice dictates that a 0.1- to 1.0- gram of the circuit for a simple push- ` 2N2222 microfarad decoupling capacitor be button- switch trigger circuit. Pull -up used between pin 8 and ground. resistor R2 is connected between pin (B) 2 and V + . If normally -open push- switch Sl is open, the TRIG- Monostable Operation button Fig. 4. Examples of (A) simple push- GER input is held at a potential very button switch triggering for the 555 The monostable multivibrator close to V + . But when SI is closed, timer and (B) transistor inverter that (MMV), also called a one -shot multi - pin 2 is brought to ground potential. permits positive -going pulses to trig- vibrator, produces a single output Because pin 2 is now at a potential ger the 555. pulse of fixed duration when trig- that is less than (V + )/3, the 555 gered by an input pulse, as illustrated MMV triggers. This circuit can be in Fig. 3(A). The output of the one- used for contact debouncing in digi- forces the collector (and pin 2 of the shot snaps high following the trigger tal circuits. 555) to near ground potential. pulse and remains in this condition A circuit for inverting the trigger Shown ïn Fig. 5 are two ac- coupled for a predetermined duration. When pulse applied to the 555 is shown in versions of the trigger circuit. In both this time expires the one -shot is Fig. 4(B). Here, a common npn bipo- circuits, a pull -up resistor keeps pin 2 "timed -out" and, so, snaps low again. lar transistor, such as the 2N2222, is normally at V + . But when a pulse is The output of the one -shot re- used in the common -emitter mode to applied to the input end of C3, a dif- mains low indefinitely, unless an- invert the pulse. Again, a pull -up re- ferentiated version of the pulse is other trigger pulse is applied to it. sistor :s used to keep pin 2 at V + created at the TRIGGER input of the The 555 timer can be operated as a when the transistor is turned off. 555. Diode Dl clips the positive - monostable multivibrator with suit- However, when the positive -polarity going spike to 0.6 or 0.7 volts, passable connection of the external cir- trigger pulse is received at the base of ing only the negative going pulse to cuit, as in Fig. 3(B). It is this mono- QI, the transistor saturates, which the 555. If the negative-going spike

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 53 V+ v+

o r J (A)

Fig. 5. Examples of (A) ac- coupled triggering of a 555 using pulses and (B) pushbutton version of the same circuit. can counteract the positive bias pro- the touchplate, the voltage (V1) drops trodes, however, the voltage on pin vided by R2 sufficiently to force the to a very low value. If the average fin- 2 (V1) drops to a very low level, forc- voltage lower than (V + )/3, the 555 ger resistance is about 20,000 ohms, ing the 555 to trigger. will trigger. A pushbutton switch ver- the voltage drops to. VI = [(V + x sion of this same circuit is shown in 20 x 103)/(R2 + 20 x 103)]. Thus, Output Circuits is 22 the voltage Fig. 5(B). when R2 megohms, As stated above, the output at pin 3 + ). This is consid- A touchplate trigger circuit is drops to 0.0009(V of the 555 can serve as either a cur- trigger- shown in Fig. 6(A). Pull -up resistor erably less than the (V + /3) rent source or a current sink, depend- R2 has a very high value (22 meg- ing criterion for the 555. ing on how you wire the circuit. The is in the li- ohms shown). The touchplate con- The same concept used output can be made TTL- compatible detector circuit shown sists of a pair of closely spaced elec- quid -level by making V + 5 volts dc. It can also Once trodes. As long as there is no exter- schematically in Fig. 6(B). be made CMOS -compatible by -up resistor nal resistance between the two halves again, a 22- megohm pull matching the 555 power supply po- of the touchplate, the TRIGGER input is used to keep pin 2 at V + in oper- tentials to the levels used in the parti- level of the liquid of the 555 remains at V + . However, ation. When the cular CMOS circuit. the elec- when a resistance is connected across rises sufficiently to short out Figure 7 shows how light- emitting diodes can used as the load for the 555. Although LEDs are used here, almost any load that draws less than 200 milliamperes could be used instead. The usefulness of the 555 is demonstrated by these circuits. There are times when you might want a LED indication when the output of the 555 is low, other times when it is high. The 555 can accommodate either need without requiring an interven- ing open -collector inverter stage. In Fig. 7(A), the LED, wired between pin 3 and ground, requires the 555 to act as a current source. When the output is low, there is no poten- LED, no current Fig. 6. Examples of (A) touch -plate sensor triggering of a 555 and (B) liquid -level tial across the alarm version of the same principle. flows, and the LED is off. When the

It In Modern Electronics 54 / MODERN ELECTRONICS / May 1990 Say You Saw V+

R2 555 R2 LED 555 R2 R3 LED

(A) (B)

Fig. 7. Light- emitting diode load used with a 555 timer in (A) current - Fig. 8. Details of use of (A) npn and (B) pnp transistor switches to increase cur- source and (B) current -sink modes. rent- handling capability of a 555. output is high, however, a potential capacity of the 555, you can add an the emitter and base are at close to the appears at pin 3, current flows in the external transistor switch, as illus- same potential, so no action occurs. LED, and the LED turns on. trated in Fig. 8, to handle the greater Even greater currents can be ac- In Fig. 7(B) the opposite connec- current. The output of the 555 is used commodated if you use a relay as the tion is shown. Here, the LED is wired to turn on and off the transistor. In load for the 555 output, as in Fig. 9. between the OUTPUT terminal and Fig. 8(A), an npn transistor version is In addition, the relay makes it possi- V + , causing the output of the 555 to shown. When the output of the 555 in ble to use the 555 in a low- voltage dc sink current. When the output is low, this circuit is low, no bias voltage is circuit with other electronics to con- the cathode end of the LED is essen- applied to the base -emitter junction trol a high voltage load circuit. tially grounded through a small re- of the transistor. This keeps the tran- Select a relay with a coil rating of sistance, so the LED is turned on. sistor in cutoff. But when the output 18 volts dc or less (5, 6 and 12 volts When the output is high, the poten- of the 555 is high, the transistor is are common). Match that voltage to tial at both ends of the LED is close to biased into saturation, causing it to the V + used to power the 555. For V + . Thus, with no differential volt- turn on hard. The "cold" end of the example, if you are powering the 555 age between cathode and anode, no load, connected to the collector of from a 12 -volt dc source, select a current flows through the LED and QI, is thereby grounded and current 12 -volt dc relay. Also, make sure that the LED is off. flows. The value of the QI base resis- the rated coil current is less than 200 In both Fig. 7 examples, the resistor is dependent upon the load cur- milliamperes. If you do not know the tor in series with the LED limits the rent and the beta of the transistor. It coil current rating, calculate it using current flowing in the LED. For most can be found experimentally. the known or measured dc coil resis- unmarked LEDs, maximum safe cur- A pnp transistor is used in the same tance (the most commonly listed relay rent is 15 mA (0.015 A). Therefore, manner in Fig. 8(B). With the pnp specification) from the formula: I,;, you should set the value of R2 to a transistor, the base must be less -posi- = (V + )/R 01. value of (V + ) /0.015 or greater. tive than the emitter so that this cir- When the current through the load cuit turns on when the output of the (Continued on page 77) exceeds the 200- milliampere output 555 is low. When the output is high,

--O NO 1 N4007 K1 1N4007 Current source

Hflnk =

Fig. 9. Current -sink and -source details of a 555 used to Fig. 10. Diodes can isolate the 555 output from transient drive relays. pulses in the external load circuit.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 57 11/Il/i ELECTRONICS NOTEBOOK 11111

Experimenting with Incandescent Lamps

acy, I had never heard of him prior to By Forrest M. Mims, III + v preparing this column.) FLA:FIIIJG The ancient incandescent lamp may seem LED Blackbody Radiation to be rather low -tech for a magazine with oti Everything above the temperature of ab- the name Modern Electronics. Actually, t nl itt i- solute zero, which is presumably every- though, some very significant advances ?L thing, emits electromagnetic radiation. have been made in the field of incandes- This is commonly known as blackbody cent lamps, about which I shall have III radiation. As the temperature of an ob- more to say later. I'll then present some RELAY ject increases, the flux of the radiation it experiments and circuits you can try that (SEE TEXT) N. emits increases and, conversely, its wave- may cast a new light on the versatility of Lt length decreases. an antique electronic component we all Blackbody temperature is specified ac- take for granted. First, let's pause for a cording to the Kelvin scale in which 0 Kel- brief review of the history of the inven- Fig. 1. A simple relay lamp flasher. vin (K) equals 273.16 degrees Celsius. tion of the incandescent lamp. - (The term degrees is not supposed to be used with the Kelvin scale but often is.) The Invention of the of an ob- Lamp Light Company before the inventor had Only when the temperature Incandescent made his first lamp. ject becomes very warm does the radia- Though Thomas Edison is generally Edison at first attempted to find a fila- tion it emits become visible. As evidence credited with the invention of the incan- ment material that could be heated to a of this, consider that the temperature of descent lamp, other inventors also played higher temperature than the carbon used an electric heating element that emits a a prominent role in this area. In 1802, En- by his predecessors, thereby providing a cherry -red glow is in excess of around gland's Sir Humphry Davy demonstrated brighter and more practical light source. 1,000 K. The filament of a white -hot that an electric current passing through a Oxides of thorium and zirconium seemed tungsten -halogen lamp may reach 3,400 thin strip of platinum would cause the good candidates, but they could not be K. If the filament could be heated to metal to emit a visible glow. All modern formed into filaments. Finally, Edison 6,000 K without melting, it would emit incandescent lamps are derived from this resorted to the carbonized thread fila- light as white as that emitted by the sun. fundamental discovery. ment, and on October 21, 1879, he dem- It's appropriate to ask why the light In 1841, Frederick de Moleyns received onstrated a lamp that operated continu- from an object at 1,200 K appears to be a an English patent for an incandescent ously for 40 hours. Two months later, he monochromatic red while that from an lamp that consisted of a two closely demonstrated a pilot light and power sta- object at 6,000 K is white. The answer is spaced platinum electrodes installed in an tion at his Menlo Park, NJ laboratory. that blackbody radiation has a very evacuated glass sphere. Powdered car- The system powered 30 lamps, any one of broad spectrum and is not monochro- bon between the electrodes became in- which could be disconnected without af- matic. Indeed, the peak wavelength of a candescent when an electrical current fecting the status of the others. cherry -red heating element at 1,200 K is flowed through the two electrodes. Incidentally, it's interesting to note around 2.4 micrometers in the infrared. In 1850, Sir Joseph W. Swan, another that, from the outset, Edison proposed to In other words, the red glow from the Englishman, devised incandescent fila- connect electric lamps in parallel circuits heating element is only a small portion of ments from paper and cotton thread. He so that the failure of one lamp would not the radiation it emits. Most of the radia- treated the thread with sulfuric acid to re- affect the remainder. Some scientists pre- tion from the heating element is invisible. move everything but the carbon. The car- dicted the parallel method would not be The peak wavelength of sunlight is bonized thread was installed inside an practical. Sir William H. Preece, for ex- around 555 nanometers in the green. The evacuated glass envelope to produce ample, said as much in a paper he read be- fact this happens to match the visible re- what Swan called an electric glow lamp. fore the Royal Society in London. For- sponse of the human eye is certainly no In the United States, Thomas Edison tunately, Edison had only three months coincidence. announced, in 1878, that he intended to of formal education in his youth, so he invent a practical electric light suitable could safely ignore the pronouncements Tungsten Filament Lamps for use in homes. Based on his reputation of formally trained scientists. Of course, as a highly successful inventor, a syndi- the parallel electric light circuit proved The simplest tungsten lamp consists of ei- cate of investors advanced Edison $50,000 practical and it greatly enhanced Edi- ther a straight or coiled tungsten filament for the electric light project. The inves- son's fame as a gifted inventor. (As for installed in an evacuated glass envelope. tors even formed the Edison Electric the skeptical Sir William's scientific leg- The filament begins to emit a dimly visi-

58 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics ble red light at a temperature of around achieved by adding to the fill gas a trace vides an exceptionally bright light source. 1,000 K. In normal operation, the fila- of a halogen, such as bromine or iodine. Moreover, after 75 percent of its rated ment of an evacuated tungsten lamp is This sets up a regenerative chemical reac- life, a tungsten -halogen lamp emits 90 typically heated to a temperature of 1,800 tion that greatly increases the permissible percent of its initial light output. to 2,200 K. The peak wavelength of an operating temperature of the filament The brilliant white light of a tungsten - evacuated tungsten lamp with a filament while simultaneously restoring the tung- halogen lamp is accompanied by several temperature of 2,000 K is around 1.5 mi- sten atoms that are boiled away. Here's drawbacks. The envelope temperature of crometers in the near infrared. Only what happens: a tungsten -halogen lamp must exceed 200 around 5 percent of the optical radiation In an ordinary lamp, tungsten atoms to 250 degrees C and may reach 350 de- emitted by the filament is visible light; the boiled away from the incandescent fila- grees C. This means ordinary glass enve- remainder is invisible infrared. ment can condense on the comparatively lopes are unsuitable. Instead, fused silica If the filament is operated at a temper- cool inside wall of the glass envelope. In a (quartz) is required. Special ceramic ature higher than about 2,200 K, the rate halogen lamp, evaporated tungsten sockets are usually necessary, and there of tungsten evaporation from it will be- atoms combine with the halogen to form may be restrictions on the operating ori- come so high that the inside of the enve- tungsten bromide or tungsten iodide. entation of the lamp to prevent thermal lope will quickly become coated with an While this gas does move toward the in- damage to the lamp's seals. opaque film of tungsten atoms. Once I side walls of the envelope, it does not con- Due to the high temperature required mistakenly applied far too much current dense there when the envelope is heated to fabricate fused silica envelopes, halo- to a miniature incandescent lamp. The to 200 to 250 degrees C by the filament, gen lamps are more expensive than are filament exploded in a brilliant flash and which may have a temperature of from conventional lamps. They must never be coated the inside of the glass envelope 2,800 t3 3,400 K. operated near combustible materials. with a shiny film of tungsten. As the gas circulates back toward the They must never be touched while in op- Tungsten lamps can be operated at a heated filament, it disassociates back in- eration. Any fingerprints or other con- temperature higher than 2,200 K if the en- to tungsten and halogen vapor when the tamination must be completely removed velope is filled with an inert gas, such as temperature exceeds 2,500 K. This pro- from the envelope before operation. Fi- argon or krypton, which reduces the cess occurs in close proximity to the fila- nally, the very high brightness of halogen evaporation of tungsten from the filament, thereby causing tungsten atoms to lamps, coupled with the ultraviolet that ment. The upper limit is 3,600 K, the be deposited onto the filament and its they emit, makes them potentially haz- melting point of tungsten. Since gases supporting wires. The cycle then repeats ardous to unprotected eyes. conduct heat, the envelope of a gas- filled as additional tungsten is liberated and The filament of an incandescent lamp lamp will become much hotter than that combines with halogen vapor. requires a finite rise time to reach its oper- of an evacuated lamp. The very high filament temperature ating temperature after a current is ap- Even better performance can be made possible by the halogen cycle pro- plied. Likewise, the filament requires a

+Sv LL FLASH RATE_ \% ^ 1 NZ

131

R1 100K F C1 L1 VDp 01, LI.- SEE TEXT

Fig. 2. An improved relay lamp driver. Fig. 3. A simple CMOS lamp flasher.

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 59 ELECTRONICS NOTEBOOK...

finite fall time to cool below the temper- +q v ature where it emits visible light when the RS is These delays are tool< current removed. "AA, sometimes known as thermal lag. Thermal lag is directly related to the physical dimensions and mass of a lamp's L Rt. R2. filament. Because of the tiny size of its fil- C .LrF LK 1coK ament, the light from a flashlight appears +9v to switch on and off instantaneously. Au- c2 tomobile headlights have very large fila- 2oOl,F ments and require a noticeable time to full brilliance when switched on 38/ +I( achieve 41 7ti1 and to be extinguished when switched y off. The same applies to filament lamps Ry used on tall antenna towers. The xenon R3 strobe lamps used on some towers flash LK -9v off and on almost instantaneously. The filament lamps used to mark most towers seem to switch off and on as if they were KEEP PowER SUPPLY LEADS SHORT. _ powered by an undulating sine wave. Fig. 4. A simple light wave receiver circuit. Relay Lamp Flashers is on A relay is physically larger than a semi- particular relay. Other low- voltage (5- tor's output. The lamp switched conductor switch, such as a silicon -con- volt) relays with a high coil resistance when QI is conducting. the Fig. 3 circuit trolled rectifier (SCR) or power MOS- may also work in the Fig. 1 circuit. Supply voltage for rated volt- FET. Also, a relay requires a drive cur- The flasher LED in Fig. 1 does not emit should not exceed the lamp's rent that a semiconductor switch does visible flashes when used as shown. Fig- age. Power dissipation of the lamp should not. Nevertheless, relays are exceptional- ure 2, a modified version of the circuit, not exceed QI's power rating. In some on, sup- ly reliable and provide a very low on -re- permits the flasher LED to flash in step applications, when LI switches sistance. Therefore, they are well suited with the incandescent lamp. This verifies ply voltage might fall enough to alter the for use in lamp flashing applications. that the circuit is functioning properly in flash rate. If this is a problem, simply dis- There are many ways to switch a lamp the event the incandescent lamp burns out. connect the lamp from the oscillator's off and on by means of a relay. Circuits In operation, R2 must be adjusted until power supply and provide it with a sepa- made from 555 timer chips are particular- the lamp begins to flash. It may some- rate supply. The source lead of QI should ly popular since flash rate and duration is times be necessary to readjust the setting be connected to the ground side of both easily varied. of R2 if the circuit stops flashing. While supplies. a visible flash, For more versatility, replace the simple Figure 1 shows a super -simple relay the flasher LED does emit lamp flasher you can assemble from a it isn't as bright as when the flasher LED two -gate oscillator with a 555 or 7555 flasher LED and a single transistor. This is used alone. (CMOS 555) oscillator chip. flasher LED switches the transistor on each time it flashes, thereby pulling in the Power MOSFET Lamp Flasher Modulating a Filament relay arm and switching on the lamp. I used an FRL -4403 flasher LED in the Figure 3 shows a simple incandescent In the spring of 1966 when I was a student A &M, I was experimenting with prototype of the Fig. 1 circuit. This LED lamp flasher circuit that uses a solid -state at Texas flashes around three times per second. switch instead of a relay. The two cross - a lightwave communication system along Other flasher LEDs should also work. coupled gates form a multivibrator that a dark country road. The receiver's detec- The relay should have a 6- to 9 -volt, oscillates at a frequency determined by tor was a solar cell installed inside the re- 500 -ohm coil, such as Radio Shack's Cat. Cl. When the value of CI is 4.7 microfa- flector of a 6 -volt lantern light. The re- it was No. 275 -004 relay does. Unfortunately, rads, the circuit oscillates at a rate of ceiver emitted a buzz when pointed sign. More surprising this relay is no longer stocked by Radio about 1 Hz. The output of the oscillator at a distant neon Shack; so you will have to search your goes to the gate of VN67 or similar power were the ringing sounds caused by the spare -parts box or borrow one from a MOSFET QI, which is switched off and headlights of some passing cars. friend if you want to experiment with this on by the changing state of the oscilla- Later, I tried pointing a flashlight at

Electronics 60 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Put Professional Knowledge and a COLLEGE DEGREE in your Technical Career through

HOME f _.. STUDY , . ti i'r,tl the receiver, which produced nothing but ther blinker or voice mode. The former um changes in noise level. Tapping the flash- yielded a range of up to 12 miles, the lat- light with a pencil caused the receiver to ter up to 0.5 mile. emit the same ringing sound produced by Incidentally, French didn't feel that a the car headlights. The ringing is caused filament lamp could react rapidly enough when the filament vibrates in and out of to a fluctuating signal to produce a mod- the reflector's focal point. ulated light beam. He attributed the mod- Add prestige and earning power to You can make a lightwave receiver to ulation to physical vibration of the lamp your technical career by earning observe this phenomenon by connecting filament: "An ordinary flashlight point- your Associate or Bachelor degree a silicon solar cell to the input of a bat- ed at the photo -tube and tapped with a through directed home study. tery- powered amplifier. Alternatively, pencil or other solid object will give a Grantham you can assemble the basic lightwave re- bell -like tone at the receiving end, prov- College of Engineering ceiver circuit shown in Fig. 4. In this cir- ing that mechanical vibration will pro- awards accredited degrees in cuit, Ql is any npn phototransistor. Do duce sound." French's conclusion was electronics and computers. not place your ears close to the speaker wrong, but he was decades ahead of me in since it is capable of emitting very loud discovering that a vibrating lamp fila- An important part of being pre- sound levels. ment produces a modulated light beam. pared to move up is holding the The rise time of miniature, low- voltage In the "Experimenter's Section" of right college degree, and the abso- lamps may range from 10 to 200 millisec- the October 1944 issue of QST (p. 38), lutely necessary part is knowing onds. This means a small lamp can be Roger Houglum observed that, "In prac- your field. Grantham can help you modulated at audio frequencies. Indeed, tically all the light -beam transmitters de- ways during World War II, some amateur ra- scribed in QST, the audio- frequency cur- both -to learn more and to dio operators experimented with optical rent from a low- impedance winding on earn your degree in the process. communicators based on voice- modulat- an output transformer is used to vary the Grantham offers two degree pro- ed incandescent lamps. intensity of the light from a flashlight grams -one with major emphasis G. Wataghin and R. Deaglio of Tori- bulb .... Tests with several of these no, Italy first published a brief note on transmitters revealed that the audio qual- in electronics, the other with major this method in a 1933 issue of the Pro- ity at the receiver end was passable on emphasis in computers. Associate ceedings of the Institute of Radio Engi- voice but downright poor when music and bachelor degrees are awarded neers (Vol. 21, No. 10, pp. 1495 -6). Hol- was used." in each program, and both pro- lis French presented complete construc- Houglum then demonstrated how a grams are available completely tion details for a battery -powered fila- small battery and low- resistance rheostat by correspondence. ment lamp transmitter and receiver in the in series with the lamp and transformer April 1944 issue of QST (pp. 22 -25 and winding would provide a pre -bias to No commuting to class. Study at 86 -88). French's system operated in ei- warm the lamp filament to around half its your own pace, while continuing on your present job. Learn from easy-to- understand lessons, with 61 help from your Grantham instruc- 3V r1 tors when you need it. I - Write for our free catalog (see address ` below), or phone us at toll -free 1 -800- 955 -2527 (for catalog requests only) i , `, and ask for our "degree catalog."

Accredited by L1 the Accrediting Commission of the 1K MO. 293 0R National Home Study Council 8a No. ZZZ GRANTHAM T1 : A uDio ouTPuT TRAJS FoRMER College of Engineering Fig. 5. An ultra -simple incandescent lamp audio transmitter circuit. 10570 Humbolt Street Los Alamitos, CA 90720

Say You Saw It In Modern Electronics May 1990 I MODERN ELECTRONICS / 61 ELECTRONICS Maroeoou...

+ y stat in series with the lamp and BI. It's Ri CL 1K .LrF much simpler, however, to achieve the same effect by altering the volume of the Li amplifier or radio. In either case, it's im- 51: PRESS FoR Ton1E to keep peak current through the R9 í portant the at which the S1 loo c filament well below point R1 filament melts. C4 R2 R3 Rti RS 1S K Speaking of melted lamp filaments, .1p,F Qy 910 K LO K 22OK 10K are you will blow some lamps TIP 3029 chances c3 while experimenting with them in modu- C2 Q3 lation circuits. Therefore, it's always a RB 2/12907 good idea to install lamps in sockets Q2 4.1K io rather than soldering their leads into the 20.12221. circuit. Be sure to keep this in mind when building the following circuits as well. Mt C C E In Fig. 6 is shown the circuitry of a (roP) transistorized filament lamp modulator/ * SEE TE kg driver that modulates a small No. 243 or 2.2.0 K. "Mr 222 lamp. As in Fig. 5, audio output transformer TI connects to a small radio Fig. 6. An incandescent lamp modulator /driver circuit. or amplifier. The critical components are LI and Ql. If current through the collector- emitter junction of Q2 is too high, LI operational brilliance. This reduced the may burn out or its life be excessively lamp's rise time and greatly improved its shortened. Momentary surges may not FCC ability to be modulated by audio frequen- harm Q2, but the average current Be an cies. The rheostat permitted the current through the transistor and LI should not to the lamp to be adjusted for optimum exceed 200 to 230 milliamperes. LICENSED operation without zapping the lamp. You can measure the current through ELECTRONIC TECHNICIAN! LI by breaking the circuit at point "X" in Lamp Modulators Fig. 6 and inserting an ammeter. Current can be reduced by lowering the level of Figure 5 shows the circuitry for an ultra - the signal applied to Tl or by inserting a simple transformer lamp modulator based Earn up to current -limiting resistor at Rx. $30 an hour on circuits published nearly 50 years ago. warm, install a heat sink and more! If Q2 becomes You can assemble this circuit in just min- on its case. For higher current operation, utes. The simple receiver in Fig. 4 will re- use a power MOSFET for Q2. Learn M home in spare lime. ceive the signal from this circuit. For ini- No previous experience needed! h - tial tests, you can use a radio as an audio No costly School. No commuting to class. Self- Contained The Original Home -Study course pre- source or replace the radio with a small Lamp Transmitter pares you for the "FCC Commercial Radio- amplifier to transmit your voice. telephone License". This valuable license While the low- impedance output from Figure 7 is the schematic diagram of a is your "ticket" to thousands of exciting most transistor radios and amplifiers can complete lightwave voice and tone light - in RadioTV. Micro- jobs Communications. 1,000 -ohm (1k) wind- wave that uses a miniature wave, Computers. Radar. Avionics and be coupled into the transmitter more! You don't need a college degree to ing of the audio transformer in the Fig. 5 No. 222 lamp as a light source. Transis- qualify. but you do need an FCC License. circuit, much better results can be ob- tors Q/ and Q2 amplify the signal from No Need to Quit Your Job or Go To School tained if you connect a second transform- the microphone and apply it to the modu- is easy. fast and low This proven course er to the first. Connect together the 1,000 - lator /driver circuit formed by transistors GUARANTEED PASS You get your cost! - transformers. Q4. Resistor R6 provides negative FCC License or money refunded. Send for ohm winding of the two Q3 and FREE facts now. MAIL COUPON TODAY! Then connect the 8 -ohm winding of the feedback to reduce the gain of the pream- r new transformer to the output of the ra- plifier formed by transistors QI and Q2. commamD PRODUCTIOnS is input preampli- 1 dio or amplifier. When Si closed, the FCC LICENSE TRAINING. Dept. 220 P.O. Box 2824. San Francisco. CA 94126 You can control the brightness of the fier oscillates and causes the lamp to be Please rush FREE details immediately! lamp by inserting a low- resistance rheo- modulated by an audio -frequency tone. NAME ADDRESS CITY STATE ZIP Say You Saw It In Modern Electronics 62 / MODERN ELECTRONICS / May 1990 BLACK&DECKER

DELUXE WIRELESS SECURITY SYSTEM

t 3 v MEASURE CURRENT Rx-4c / LL NO 24 3 OR NO 222.

Q2 T-1 2 fa 2222. Intelligent home security system. Detects intruder during entry. Wireless for easy installation. Difficult to defeat because of new. advanced technology. IN Lamp command flashes lamp upon intrusion. Signal relay -relays entry sensor intrusion signal from a remote area of your home to controller. Tamper resistant. 85 decibel alarm on inside siren. BSI L I< Piercing 120 decibel outside siren. Fail -safe battery back -up. SEE TEXT Low battery warning. 2 Year Warranty! Ti : AUDIO ouTPvr TRANS FORMER Includes: It TRANSISTOR 8 entry sensors, 1 system controller (includes AMPLIRIER inside siren), 1 signal relay. 1 lamp command, 1 outside siren. 2 window stickers.

1 yard sign, and complete hardware and Fig. 7. A transistorized incandescent lamp voice and tone transmitter. batteries.

Frequency can be changed by altering the will be projected onto the wall when Due to a special ar- Manufacturer's the rangement, we values of RI, CI or both. filament is at the focal point of the lens. were able to obtain Suggested Retail The circuit should be powered by three This simple a large inventory of $698.00 demonstration shows that a these wireless se- 1.5 -volt cells connected in series. Before small fraction of the light emitted by a fil- curity systems. As DAMARK PRICE: connecting the cells a result, we can to the circuit, how- ament can be collected and collimated in- now offer them to ever, connect the microphone and care- to a narrow beam. you at HUGE SAV- INGS! $29999 fully check all wiring to make sure no er- You can make your own lens collima- Item No B-1984-133389 rors have been made. When power is ap- tor or use binoculars or a small telescope. Insured Ship /Hand.: $15.00 plied, the lamp should glow at around My son, Eric, and I have placed a small half its normal brilliance. If it glows a lamp at a telescope eyepiece and project- FOR FASTEST dim yellow in color, increase pre -bias cur- ed an image of the filament on a building SERVICE CALL rent by connecting a second 10 -ohm resis- more than a hundred meters distant. We tor across R10. then sent voice and music signals over the TOLL FREE When you speak into the microphone, collimated beam to a receiver. the lamp filament should flicker. Press- Since only a tiny fraction of an incan- 1 -800- 729 -9000 ing SI may cause the lamp's brightness to descent lamp can be collected by a lens, a

change, will C - but the lamp not flicker. reflector provides a more -efficient means l MasterCard Most dynamic microphones should for collimating light from a lamp. A las- work well with this circuit, but high -im- er, of course, provides a much better pedance types will not work. Though I source of collimated light. But flasl.light DAMARK INTERNATIONAL, INC. used a TIP3029 for Q4, other npn power lamps and simple lenses are very inexpen- 6707 Shingle Creek Parkway, Manneapolrs. MN 55430 Customer Service 612 5664940 transistors should also work. sive and with them, flashing signals, mu- Please rush me:_ Black & Decker Security sic and voice can be sent a fair distance on System(s) @ $299 99 each. plus $15.00 sah each. a dark Item No. B -1984- 133389 night. MN res. add 6% sales tax. You may wish to do as I've Going Further done and Name assemble filament lamp transmitters and Address Try placing a magnifying lens between a receivers inside plastic 6 -volt lantern light Cdy.State Zip small incandescent lamp and a white Check/MO VISA Master Card Discover housings. These large flashlights are Card No wall. As you move the lens back and equipped with reflectors and plenty of Exp. Date / Ph I forth, an image of the lamp's filament space for circuits and batteries. At' Signature

DELIVERY TO 48 U.S. STATES ONLY

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 63 111/ill/SOLID - STATE DEVICES IIII Filters, FIFOs and other Devices

typical connection is shown in Fig. 1. and programmable systems to make the By Joseph Desposito In Fig. 1, the SSM -2044 is connected as filter(s) sound the same for an identical a four -pole low -pass electronic music fil- input control voltage. For best control re- This month, we'll take a look at several ter. The differential signal inputs will ac- jection, the control summer and input at- types of analog and digital devices. The cept any signals up to ± 18 V peak -to- tenuator should be designed so that maxi- analog devices are a voltage controlled peak. If two oscillators are used in a mum swing at the 2044 control pin cor- filter a low -noise filter and /oscillator, voice, the output of the second should go responds to extremes of the intended and dual low -power operational quad to the opposite filter input from the first sweep range when the control summer is amplifiers. The digital devices are an with a 3 -dB signal level difference. This driven to the supplies. With the values 80052 BASIC processor and a family of can be accomplished by scaling the input shown, one will obtain ± 90 mV at the in- bidirectional FIFOs. attenuators as shown, thus preventing put pin, which corresponds to a 1000 -to -1 cancellation as the oscillators phase with sweep range for ± 15 V supplies. Analog Devices each other. The V /octave trim and the Tel Labs compensating resistor are A Voltage-Controlled Filter /Oscillator. The sense of the Q control is from temperature- where the filter As an alternative to switched-capacitor GND up with minimum resonance at required in applications musical intervals filters, Precision Monolithics Inc. (1500 GND. Oscillation will occur when the has to produce accurate Space Park Dr., P.O. Box 58020, Santa current into the Q pin reaches approxi- when in oscillation. If this is not neces- op amp feedback net- Clara, CA 95052) makes a four -pole volt- mately 425 A. With the input resistor sary, the control work the Tel Labs resistor can be re- age- controlled filter /oscillator. This shown, this corresponds to +7.5 V. and adds voltages placed by 1% 300K- and 1K-ohm resis- product, the SSM -2044, offers a 1 -MHz The control summer bandwidth and is appropriate for a wide from various control sources, such as the tors, respectively. dB low -pass range of applications, including medical fc panel control, transient generator, Ifo, The SSM -2044 is a - 24 -1 variable cutoff imaging, ultra -sound and instrumenta- etc. Any number of signals can be summed filter with a 10,000 -to frequency is deter- tion systems. However, the design of the by applying them through resistors to the frequency. Cutoff by a control voltage, making the SSM -2044 has been optimized for use as summing node of the op amp. Frequency mined for real -time analog filtering an electronic music low -pass filter. A offset adjust is required in polyphonic device ideal

- SIG IN 100K 2001 t 2002 0 -V SIG IN 68K o M 13K O CONTROL o w 0 01.1

13200

r 001.1 0011

TEL LABS TYPE 061. TC. _ -3600 ggm(C (OPTIONAL. SEE BELOW) 50K ALL COMPONENTS 5 °. UNLESS NOTED VO N V FRED OFFSET ADJ

Fig. 1. Precision Monolithics' SSM-2044 voltage -controlled filter/oscillator is shown here connected as a four -pole low -pass electronic music filter.

64 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics under microprocessor control. A unique feature of the SSM -2044 is its on -chip resonance control, which can produce a low- distortion sine wave for use in voltage -controlled oscillator (vco) 250 applications. With a dynamic range of 90 i l dB and 1 -MHz bandwidth, the SSM -2044 200 AI* is a low -noise alternative to switched -ca- I pacitor filters in a wide variety of applica- 50 1 tions, including antialiasing and recon- Í struction filtering. J ! - -- - i -55, 125°C The SSM -2044 can operate with supply 25, voltages ranging from ±5 V to ± 18 V and, therefore, offers better pc-board layout flexibility than some CMOS devices. The SSM- 2044's performance and characteristics are guaranteed over the National 0°C to 70°C temperature range. The pro- 0 2 4 6 8 10 12 14 16 Semiconductor duct is priced at $2.60 each in quantities of 100 and is available in 16 -pin epoxy SUPPLY VOLTAGE (V) DIP packages. Eighth-Order 100 -KHz Low -Noise Fil- National Semiconductor's new micropower operational amplifiers require a current of ter. Linear Technology (1630 McCarthy only 40 µA per amplifier. The curve shows current- versus - voltage for the LPC662. Blvd., Milpitas, CA 95035) has announced the LTC1064 -3, an eighth -order filter with a maximum corner frequency of 100 kHz and only 80µV (rms) total wideband operational amplifiers that require a sup- The devices are fabricated with Na- noise. The new device requires no exter- ply current of only 40 µA per amplifier. tional's advanced double -poly silicon - nal components for a 100 -kHz filter im- The devices also feature true single -sup- gate CMOS process and have an operat- plementation with a total harmonic dis- ply operation, rail -to -rail output swing ing range of +4.75 to + 15.5 V. tortion of 0.005% or less. and extremely low input bias current. The LPC660 and LPC662 are available Applications for the device include an- The LPC660 quad and the LPC662 in 14- and 8 -pin plastic DIPs, respective- tialiasing filters, smoothing filters and dual op amps are micropower versions of ly, in industrial temperature range units tracking high- frequency lowpass filters. National's popular LMC660/662 CMOS priced at $1.40 in quantities of 100 for The LTC1064 -3 is a monolithic lowpass op amps. Since they require very little the LPC660IN, and at $0.90 for the Bessel filter that provides a linear phase supply current and can operate from a LPC662IN. response over its entire passband. An ex- single -ended power supply ( + 5 to + 15 ternal TTL or CMOS clock programs the V), the new op amps are ideally suited for filter's cutoff frequency with clock -to- many low -power applications. Examples Digital Devices cutoff frequency ratios of 75:1 or 150:1. include battery -powered hand-held me- The LTC1064 -3 has low wideband noise Trs and medical instrumentation. 80052 -BASIC Processor. The 80C52- and low harmonic distortion, even for in- Types of circuits that take advantage BASIC processor from Micromint (4 put voltages as high as 3 V (rms). of the features of these op amps include Park St., Vernon, CT 06066) is a CMOS The LTC 1064 -3 is available in a 14 -pin low- leakage sample- and -hold circuits microcontroller with on -board BASIC. DIP and 16 -pin surface mounted SOL and low- frequency filters. In a filter cir- Based on Intel's popular 8052, the 80C52- package. Pricing in quantities of 100 and cuit, the low input bias current of the BASIC contains a full BASIC interpreter up for the military temperature range is LPC660/662 allows the designer to use in on -chip ROM. This implementation of $27.85 and for the commercial tempera- larger resistor values and, therefore, BASIC includes the following features: ture range is $9.95. smaller capacitors, saving board space BCD floating -point math; built -in real - CMOS Op Amps Require Only 40 Micro - without degrading performance. In a time clock; access to programs in RAM, amps. National Semiconductor (2900 sample -and -hold or peak- detector cir- EPROM or EEPROM; built -in radix Semiconductor Dr., P.O. Box 58090, cuit, the same low bias currents improve conversion from hex to decimal and deci- Santa Clara, CA 95052) has introduced signal accuracy by decreasing the leakage mal to hex; ability to handle interrupts in new quad and dual micropower CMOS current from the holding capacitor. BASIC or assembly language; and gen-

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 65 SOLID -STATE DEVICES...

rectional FIFOs that are optimized for PROCESSOR 2..345678.9.L0 use in microprocessor communications. BUFFER The family includes four members that --L VCC U7 74HCT245 are "bus- matching" eight -bit peripherals 11 Two addi- ADO \ P0.0 39 fID0 AS B8 to any size microprocessor. A01 A7 B7 12 tional members of the family can be used 7 P1.4 AD T11111. 0E.11.111 A6 to match 16 -bit microprocessors to other 6! 03 P1.5 IOU AS es .w-4 . S B 16 -bit systems. P1.6 'In' D. =HI A4 15 B3 16 The matching" biFIFOs, with an P1.7 5 A3 "bus- 3 1 A A2 B2 x18 width on one side and an x9 on the -oi PST AOi Al 81 1 other, act as funnels interfacing 16-bit i systems with eight -bit systems. These bi- . A+B EN P3.0 PXD ol FIFOs are available as 1K (IDT7252 '1+P3. 1 \ Tx0 INGE Jl 9 IDT72520) or 0.5K (IDT7251 and 'P3.2\ INTO ALE and P3.3 INT1 IDT72510) devices. The xl8 to x18 bi- í°_P3.4 T0 PSEN FIFOs are also available as 1K (IDT72521) P3-` T1 A15 or 0.5K (IDT72511) devices. ' P3. 6 WA A15P2.7 A14 An IDT biFIFO gives designers a sin- P3. , RD A14\P2.6 A13 \ P2.5 A13 gle -chip buffering solution that replaces 1+ A". Al2 P2. 4 up to 17 devices. This translates into 24 All s P2.3 higher integration, reduced board space 'AL 1 A10P2.2 Another A9 P2.1 22 and lower power consumption. A8 \ P2.0 21 benefit is that the x18 to x9 width allows designers to match the bus from RISC 8031 OR MICROMINT$ 8 U! 80C52-BASIC microprocessors to any standard -bit or 16 -bit peripheral. r A pass- through feature of the biFIFO provides a direct data path through the si biFIFO, while bypassing buffers, to ADO 1._q: U4 speed communication and eliminate ex- AD2 AC' 75176 A04 AC'` tra external logic. ¡\\01 \ TXD \. A06 AD Eight flags are available on the bi- 12N290? RXD GND + ONO FIFOs. Empty, full, almost -empty and Ae A9J JP18 /A10 N A11/ T/~~ almost -full are generated internally for Al2 A13/ both FIFO memories. Programmable (1A14 A15/ flag offsets for almost -empty and al- GND- ONO most -full can be set at any depth. Pro- 19 20 - see grammers can assign any four of the eight )6 flags to four external flag pins. The family of biFIFOs features a pro- chip with on -board BASIC language interpreter in Micromint's 80052 -BASICprocessor cessor interface that determines the "per- flexibility and a wide variety offeatures. ROM offers tremendous sonality" of the biFIFO by programming the flags and the DMA handshake struc- eration of all timing required to program power consumption while retaining all ture. On the IDT72521 and the EPROMs and EEPROMs. The 80C52- RAM, register and flag status informa- IDT72511, the processor interface pro- BASIC's full language resources allow tion. The microcontroller's features grams the I/O logic as well. software development directly on the make it a good choice for intelligent pow- The IDT7251 and IDT7252 in 48 -pin target hardware. er-sensitive and temperature- sensitive plastic DIP packages sell for $77.49 and The 80052 -BASIC is guaranteed to applications. The 80C52-BASIC is avail- 86.10, respectively, in 100 and up quanti- perform without error at clock speeds able at $14.50 each in quantities of 100. ties. The IDT72520 sells for $90.41, and 52 from dc to 12 MHz over the full industrial A Family of Bidirectional FIFOs. Inte- the IDT72510 for $81.36 in a -pin temperature range. If power consump- grated Device Technology (3236 Scott PLCC package. The IDT72521 and the tion is critical, the 80052 -BASIC offers Blvd., P.O. Box 58015, Santa Clara, CA IDT72511 are $94.93 and $85.43, respec- two reduced -power modes that slash 95052) has announced a family of bidi- tively, in a 68 -pin PLCC package.

66 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics X91111 PC CAPERS 11111111 Laser Wars

By Ted Needleman

I have to admit to being a bit ambivalent about Hewlett- Packard. Its test equipment is first rate, as are its calculators. On the other hand, I've never been all that impressed by the company's Vectra PC line, considering it overpriced and with a keyboard not up to H -P's fine standards, as demonstrated on its other equipment. And PAM, H -P's Personal Application Manager, gives me hives - it's just nowhere near as well done as many other DOS shells, including some inexpensive shareware products, such as Magee software's Automenu. Where H -P does shine in the PC world, though, and shine brightly, is in the area of laser printers. As detailed in last month's review of the LaserJet IIP, Hew- lett- Packard introduced the world's first affordable desktop laser printer in 1984, and has lead the market ever since. When I reviewed the $1,495 IIP last Hewlett -Packard's new LaserJet III laser printer. month, I wondered at H -P's marketing. After all, the IIP gave you everything except the speed of its Series II, and a few things such as rotatable fonts that the II, which it replaces. Though it uses the The LaserJet III contains the same bit - more expensive printer doesn't offer. It same laser engine, it is nonetheless a ma- mapped Courier fonts as its predecessor. seemed destined to blow away the sales of jor upgrade to H -P's laser printer line. In addition, though, are two new type- its mid -range laser printer line. While the internal mechanicals remain faces, CG Times (a Times Roman face) The question was answered on March the same, almost everything thing else and Univers, a sans serif face. These two

1st, with the introduction of the LaserJet about the printer has been improved. new faces are scalable from 1 point to III. I've had one for several weeks now, The most noticeable difference, on a 999.75 points (over 13 inches high) in and have to admit I'm impressed. H -P first look, is the case. Although the print- 0.25 -point increments. They are avail- has really done its homework with this er has the same basic footprint as the Se- able in medium, bold and italic weights. printer, and set some new standards, ries II, it has had a complete styling rede- One major difference from the old font both in features and price /performance. sign and looks much sleeker. The control technology used on the Series II is that the panel is still located on the front right side new built -in fonts are scalable on- the -fly. H-P LaserJet III of the printer but has also been rede- As with PostScript fonts, you don't have signed to be easier to use and matches to have a specific type size before you can Hewlett- Packard has gone through four that on the IIP. Even though the paper use it. Both the internal scalable fonts, releases of their 8 -ppm laser printer. The cartridge has been refined and smoothed, the internal bit- mapped Courier fonts, original LaserJet gave way to the LJ Plus, along with the case, you can still use any and any downloaded softfonts can also Series II, and the Series IID, the latter a Series II paper cassettes you might have. be rotated. Unlike the Series II, you no duplex printer able to print on both sides The cassettes look sleeker, but are me- longer need portrait and landscape fonts; of a piece of paper. H -P's IIP, the 4 -ppm chanically identical to the older ones. the portrait fonts can be rotated when personal laser reviewed here last month Inside the new case are several en- producing documents in landscape mode. redefined the low end of the laser printer hancements that will redefine what H -P One major benefit of this is that while market. While the IIP defines the low end compatibility means in the beginning of you can use Series II (and earlier) font of the laser market, the new LaserJet III the '90s. These include a new internal cartridges in the LaserJet IlI's cartridge will most likely do the same for the 8 -ppm font technology, an upgrade to H -P's slots, the new font cartridges and down- market in laser printers. PCL language (PCL 5), and improved load softfonts being produced for the IIP The latest model is based on the same output though a technology called "Re- and LaserJet Ill printers contain only Canon SX laser engine used in the Series solution Enhancement." portrait fonts. Because the landscape

Say You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 67 NAM RADIO PC CAPERS ... IS FUN!

It's even more fun for begin- fonts have been eliminated, these collec- ly available, such as UltraScript, Go- ners now that they can oper- tions generally include more fonts for the Script, or Freedom of the Press. These ate voice and link computers same (or lower) price. cost considerably less, but require that just as soon as they obtain On- the -fly font scaling and rotation you first print a file to disk, then process their Novice class license. You features are derived from the AGFA the file through the software package to can talk to hams all over the Compugraphics Intellifont technology print it. world when conditions per- that has been incorporated into the new As you might expect, this takes consid- more time than just printing the mit, then switch to a repeater PCL 5 version of H -P's Printer Control erably with a hardware emulation cartridge. for local coverage, perhaps Language. There are several other major file benefits that PCL 5 provides. AutoFont Pacific Data Products makes a Post- using a transceiver in your car support, which provides the font metrics Script cartridge for the Series II and IIP unit. or handheld for outline and bit- mapped fonts directly laser printers, so I wouldn't be at all sur- to an application that supports this tech- prised to see these companies bring one nology (and most major software ven- out for the LaserJet III (if they haven't al- dors have committed to do this), elimin- ready done so by the time this review ap- ates the user having to provide this infor- pears). Pacific's cartridges for the IIP mation when installing new applications and Series II cost under $700, so if they or fonts. follow the current pricing, it will be sever- Recently, Al Burawa (Managing Edi- al hundred dollars less than an equivalent tor of ME) and I were discussing the IIP unit from H -P. An additional emulation printer. Al made the comment that he cartridge will give the LaserJet III, Epson wished the IIP could also make use of the FX and IBM Proprinter compatibility. A HPGL graphics language -it would hardware option will add AppleTalk to make the printer particularly appropriate the printer, easing its use with Apple's for CAD applications such as producing Macintosh computers. board layouts and schematics. Well, Al, From a technology point of view, the maybe H -P has our phones tapped, be- most impressive new feature of the Laser - cause this feature has been implemented Jet Ill is "Resolution Enhancement." in the LaserJet III. PCL 5 provides vector One problem with any printer that uses graphics for the first time on the LaserJet! dots to form characters is that these char- Vector graphics is a method of produc- acters often show some jaggedness. ing graphics by drawing a line between While laser printers use extremely small two previously defined points. This capa- dots that minimize these effects, a close bility is achieved by incorporating HP- examination of laser output, especially of GL2, the graphics language used in H -P's extremely large or small type, often re- Your passport to ham radio adventure is 5. it will take veals the dot heritage of this printing TUNE -IN THE WORLD WITH HAM plotters, into PCL While use method. The jaggies are more noticeable RADIO. The book tells what you need to software vendors some time to make where a curves, or at the inter- know in order to pass your Novice exam. of this feature, eventually this feature will character valleys Two cassettes teach the code quickly provide many of the special effects now section of two lines, such as in the and easily. available only on PostScript printers. of letters such as y and x. Enclosed is my check or money order for Another feature of PCL 5 is the ability Two factors contribute to the "jag - $19.00 plus $3.50 for shipping and handl- to overlay images in either a transparent gies." The first is that all characters are ing or charge my or opaque mode. This feature is standard made up of dots of the same size. This dot ( ) VISA ( ) MasterCard ( ) Am Express in most PostScript applications, and its size is most obvious where a character ta- Signature inclusion in PCL 5 brings the LaserJet III pers off to a point, such as at a serif. An- Acct. No closer to meeting the requirements of other factor is that the dots are all placed Good from Expires - both PCL and PostScript users. in the same plane. Curves are constructed Name If you simply must have PostScript by "ramping" the dots -leaving several H successive lines. This creates a Address compatibility in your PCL printer, -P dots off will be introducing a PostScript emula- stair -step effect that can give a curved tion in a few months. If you can't wait, or area a jagged appearance. H -P's "Resolution Enhancement" City State Zip don't want to spend the thousand -or -so ME dollars that this cartridge will cost, you fills in the gaps with smaller dots, smooth- can gain PostScript compatibility by using the ramps much like filling in a gap in THE AMERICAN RADIO RELAY LEAGUE In the vertical mode, 225 MAIN ST. ing one of the software products current- a wall with spackle. NEWINGTON, CT 06111

CIRCLE NO. 1SS ON FREE INFORMATION CARD 68 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics these smaller dots are created by lowering add -in boards, such as Intel's Visual the new printer is any faster than the Se- the power of the laser beam, resulting in a Edge and others available from Laser - ries H. It doesn't seem to be, but then the smaller charge on the photoconductor Master and DP-Tek, also allow a Series II Series II has always delivered perfor- drum and less toner being placed on the printer to produce up to 1,000 dpi hori- mance very close to the 8 pages per min- paper during printing. zontal resolution. ute Hewlett- Packaged claimed for it. AE Being the leader has both advantages In most other respects, the LaserJet III and disadvantages. If you are successful, is very much like the Series II. It uses the you get to set the standards. At the same same EP -S cartridge containing the pho- Manufacturer Address time, the competition gets to ride on your toconductor drum, developer and toner, LaserJet III coattails by offering the same features for and sets up in about 2 minutes. The new Hewlett- Packard Co. less money or more features for the same PCL 5 is downward compatible with ear- (800) 752-0900 money. This has proved in vola- true the lier versions. It worked perfectly with all Price: $2,395 tile laser printer market. With the Laser - of the applications I had configured for a 1 MB memory board: $495 Jet III, H -P has set a new level of feature Series II printer. Without performing a 2 MB memory board: $990 performance. At the same time, it has al- formal printer benchmark, I can't tell if so set a new level of price performance. The Series II, with 512K of RAM, was priced at $2,695. The LaserJet III has PIMABLE-TV BOXES REMOTE CONTROL KEYCHAIN 1MB of RAM built in and can be ex- Complete w /mini transmitter and +5 vdc RF receiver panded to 5MB. It also has PCL 5, scal- Descramblers Converters Fully assembled including plans to build your own auto alarm able on- the -fly fonts and font rotation, Scme Of The Best Prices In Town Write for more information Quantity discounts available and the "Enhanced Resolution" feature. Check, Visa or M/C It gives you all of this for $2,395. And H- T.J. SERVICES ONLY $24.95 Add a$ 3 shipping P has sweetened the pot even more by 312.-979-8356 VISITECT INC. / Dept. M (415) 872 -0128 dropping the prices on its disk -based scal- PO BOX 5442, SO. SAN FRAN. , CA 94080 able typeface products from $195 to $99. I thought the IIP was a good deal at $1,495. I still do. But the LaserJet III, at LEARN ELECTRONICS FROM VHS VIDEO TAPES! $900 more, gives you a lot for that extra $900. If the IIP is a good deal, the Laser - Jet III is a great one. It's going to make choosing between them a hard choice. Horizontal smoothing is accomplished PREPARE FOR by using smaller dots and by offsetting dot placement by varying on /off timing THE FUTURE... of the laser beam. This allows dots of in- creasing or decreasing size to be placed Video Tapes close together, creating a gradually rising NOW! Designed Especially ramp rather than an abrupt "stair- step." For The Electronic Enthusiast! The enhancement can be set to light, medium or dark (or turned completely off) 1989 from the control panel. 1 Price Resolution Enhancement is not some- ELECTRONICS AND YOU -PART -DC $32.95 Series circuits, parallel circuits, combination of series- parallel circuits. OHMS law. voltage, current and resistance. thing that jumps out at you. If you aren't ELECTRONICS AND YOU -PART 2 -AC Price $32.95 looking for the effect, you might not no- AC theory, coils, transformers, capacitors, filter circuits and how they are used in actual circuits. tice any difference. The overall visual ef- ELECTRONICS AND YOU -PART 3- SEMICONDUCTORS Price $32.95 An introduction into the world of semiconductors. Starts with semiconductor theory then proceeds into 15 different fect, though, is that the pages just look semiconductor devices. Shows how an integrated circuit is designed and built. slightly crisper, as if they were printed at ELECTRONICS AND YOU -PART 4 -POWER SUPPLIES Price $32.95 a higher resolution. If you already have a Starting with the transformer then to various types of rectifier circuits. Filter circuits. voltage protection. Trouble- shooting different parts of the power supply. Series II LaserJet, and really want the en- VCR MAINTENANCE AND REPAIR Price $32.95 hanced resolution, you won't have to sell Designed for the average VCR user. Learn how to clean the tape path, replace belts plus more. A must for home or discard your old printer to get it. H -P maintenance. INTRODUCTION TO VCR REPAIR Price $59.95 will offer an upgrade later in the year that Shows how the VCR processes the luminance, chromance and audio signals in playback and record modes. Servo will give Series II owners PCL 5 and Res- systems for controlling the capstan motor and video drum cylinder. Many more aspects of VCR repair. olution Enhancement. Also, third -party Mail check or money order to: UCANDO or call us at: (513) 54gú113 P.O. BOX 386 _ORDER nt3W 1 VISA and MASTERCARD accepted GREENVILLE, OHIO 45331 BE A SUCCESS WITH UCANDO VIDEOS! INFORMATION CARD CIRCLE NO. 156 ON FREE 69 Enhance Your Math Prowess (from page 23)

on, the LCD shows a status line, four bar. With all of these functions, learn- storage areas (the first four levels of ing to do even basic things like enter- 1 _i _ -. and a ing a formula, plotting a graph and 1 Iha(,rI,;'t.) the stack for RPN calculations) r menu bar. With a press of two keys, doing symbolic math takes a commit- n=0 the screen blanks and becomes an ment -one that includes reading a electronic chalkboard where you can manual of over 800 pages. And it is enter formulas almost exactly as they unlikely that you can get by without appear in a textbook (see Fig. 1). the manual, for the HP 48SX learn- 1. Writer mode of Fig. The Equation Nothing special is required to enter ing curve is a steep one, and perform- the the HP 48SX displays a formula equations in this way; just press the ing advanced functions is not an in- way it would appear in a textbook appropriate keys. tuitive process. or journal. Of the 49 keys, 12 perform at least The difficulty in learning the HP four functions, and 22 perform at 48SX stems from its inability to per- (LCD), two expansion slots, an RS- least three. Like most calculators, the form functions while in the equation 232C port and a two -way infrared in- main function of the key is printed on mode. To enter the equation mode terface. All of this is contained in a its face, and its other functions are you press the unit's orange arrow key product about one -third the size of a printed in different colors around it. and Equation key. This blanks the standard textbook, powered by three However, some things, such as low- display. Then you press the alpha key AAA cells that will last for about six er -case characters, are not even in- twice (to lock it) and enter an equa- months with normal use. cluded on the keyboard, most likely tion, such y = x2, which displays just Naturally, features like the above due to the lack of space. To get a key as it would in a textbook. Once do not come cheap. At a suggested to perform a function other than the you've done this, you are staring at retail price of $350, the HP 48SX can one described on its face, you first an equation. Logically, you expect to be considered the Mercedes Benz of check the color of the function you be able to do something with it, such scientific calculators. And you can want and press a special blue, orange as plot it. If you try to plot it by press- even order advanced options for the or alpha key, before pressing the key ing the orange arrow and Plot keys, already well- equipped base model. itself. You can select functions from you get an error beep. The options include a serial interface the menu bar by pressing one of the To actually plot the equation, you to connect to an IBM PC or an Apple six keys placed just below the display. have to enter it on the stack first by Macintosh for $99.95; a 32K RAM If you are familiar with RPN cal- pressing Enter, then press Plot, then card for $79.95; a 128K RAM card culators, you'll have no trouble per- press STEQ (store equation) on the for $250; an HP Solve Equation Li- forming operations on numbers. The menu bar, then press PLOTR (plot pa- brary Application card for $99.95; sequence of keystrokes for most op- rameters) on the menu bar, and then the and a portable infrared printer, erations is press a number, press En- press DRAW on the menu bar. And HP 82240B, for $135. ter, press another number, and then this is just one way of doing it! press the operation. Sometimes you Suffice it to say that advanced op- Operating the HP 48SX can press an operation right after erations performed on the HP 48SX The first things you notice about the pressing the first number, such as require a lot of keystrokes. And any- HP 48SX are its 2.5- by 1.4 -inch with the square -root key. time you are in the equation mode or LCD and the keys and key legends on If the above sounds easy, it is. But the plot mode, the calculator takes its face. What you're less likely to no- be forewarned: the HP 48SX has some time to do its work. For exam- tice are the serial port and infrared more than 2,100 functions, some hid- ple, it takes 15 seconds to draw the LEDs on its back panel. When turned den in the deep recesses of the menu plot for y = x2. It's possible to draw diagrams with the HP 48SX. The way to do this is to press the orange arrow and Plot keys and select PLOTR and ERASE from the n i nmurr 4B 22 T 1 menu bar. Then you press the orange e::: ::: :s AT 4aT arrow and Graph keys. This brings 4' 90 a blank screen. You then press GEN:ITY you to :OL 4 54 the Nxt key to access the drawing SOLO EQN OARS CM +STK EIUT menu. This menu bar has commands such as DOT + , DOT - , LINE, BOX and Fig. 2. The HP 48SX includes commands for drawing diagrams. CIRCL. You use these commands in

70 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics conjunction with the cursor keys to ists for that menu. For example, if like this: « ». To facilitate en- draw pictures. A drawing done this you choose AREA, a menu appears tering commands such as IF and way is shown in Fig. 2. with MA2, CMA2, B, YDA2, FTA2 WHILE, you can bring up a program- To do unit conversions on the HP and INA2. To attach units such as in- ming menu bar by pressing the Prg 48SX, you press the orange arrow to a number, you type the number key. This lets you enter a command and Units keys. This brings up the and press the key under IN ^2. by pressing a single menu key. To units menu. The menu displays Like many Hewlett -Packard cal- store a program, you place it on the words like LENG, AREA, VOL, TIME, culators, the HP 48SX is program- stack with the Enter key and then SPEED and MASS. To see more menu mable. To enter programs into the name it by pressing the single quote items, you press the Nxt key. Many HP 48SX, you begin by pressing the (') key, typing the program name, menu words have a little bar on top of orange arrow and program symbol and pressing the Sto key. To run a them to indicate that a sub -menu ex- keys. The program symbol key looks program you type in the name of the

HP Kit Turns Dedicated Hardware into PC Software

One of the options available for the HP 48SX scientific expandable calculator is a serial interface kit. Although the kit was not available to Modern Electron- ics for a hands -on review at press time, we can give you some information about it. The kit comes with a serial cable and data communications software on 3.5- and 5.25 -inch disks. The cable and software link the HP 48SX to IBM PC and compatible computers and Ap- ple Macintosh computers. To access the serial port from the HP 1"1117:7010), 48SX, there is an Ibo key that brings up BM a communications menu on the display. The menu has the following choices:

SEND RECV SERVE KGET FINIS SETUP

The only one of these choices that has a sub -menu is SETUP. This menu lets you configure the I/O port for wire or infrared transmission, and ASCII or binary transmission. It also allows you to select a baud rate between 1,200 and 9,600 bps, set the parity, set the checksum type, and set the translate code. When you press the NXT key, five more menu choices appear:

RECN PKT KERR OPENI CLOSE

Another press of the NXT key reveals PC using the Kermit protocol. outs and use the computer's disk drive five additional menu choices: The interface kit gives the advantages to store data and programs. of using a large monitor and standard Operating the HP 48SX from a PC is XMIT SRECV STIME SBRK BUFLE QWERTY keyboard for programming like adding software to the computer. the HP 48SX. While linked to a PC, the Unlike traditional software, however, In general, these commands allow the HP 48SX can share the computer's the HP 48SX can be disconnected from HP 48SX to send and receive files with a printer to generate high -quality print- the computer and used alone.

Sa} You Saw It In Modern Electronics May 1990 / MODERN ELECTRONICS / 71 lator. Then you press the orange ar- should give you an answer of 2x. The FLOT THE row and i/o keys. This brings up an calculator gives you an answer that I/O menu. This menu contains all shows the derivative of x with respect commands needed to send data along to x multiplied by 2x raised to the 2-' the IR link or through the serial port. power -a correct answer but not ex- 48SX uses Kermit protocol actly what most people expect. ¡TEO SEW ® CODRD (AMA MI The HP to transfer data. The unit -management function of the calculator converts 148 different ZOOMiPt I H units in 16 categories. In addition to HP 48SX Features these, you can build compound The wealth of features of the HP units, such as kilograms per second 48SX reminds me of the sign you of- (kg /s), or add your own units. see it, Among its other features, the HP Sidi EC= coaRO =[D1 ten see in stores: If you don't ask for it! For the HP 48SX, you 48SX has a built -in clock (and, there- could say: If you don't know if it can fore, you can set alarms and do date perform a mathematical operation, and time arithmetic), a wealth of trig- check the manual! You'll probably onometric, hyperbolic, exponential, find the feature you are looking for. logarithmic and statistical functions, If you want to operate in the and the ability to work with complex graphics mode, the HP 48SX can numbers, vectors, arrays and even zoom in on a portion of a graph and binary numbers. automatically find roots, slopes and The huge manual that comes with local extremes, as shown in Figs. the calculator does a respectable job 3(A) through 3(E), as well as find the in terms of style and presentation, area under a curve. The unit can also but is lacking in one important area. display graphs in eight formats: It fails to give you an overview of the function, bar charts, histograms, more than 2,100 functions that the scatter plots, conic section, polar, calculator can perform. For exam- parametric and truth plots (see Fig. 4). ple, it would be nice to have a sheet LOCAL F1 I Fa I MLRM FC iUEap In equation -writer mode you can that shows the complete menu struc- enter integral signs, derivative signs, ture. It would also be nice to have a summation signs (sigma), greek let- list of all the hidden operations in one ters and superscripts. Any division place-operations such as lower -case EXTRA 2 -3'11100190265' operation is shown as one number letters. With enough effort, the man- over the other. About the only thing ual will teach you how to use the cal- do is subscripts. Once culator, but it doesn't do much to Fig. 3. Some of the things you can do you can't enter you can per- streamline the learning process. with the HP 48SX (top to bottom): you enter an equation, such as The serial port on the back panel is plot an equation; zoom in on points form algebraic operations, or solving for used to connect to an IBM PC or Ap- of interest in the plot; obtain values collecting like terms and ple Macintosh. A special cable is for the roots of the equation; find the one variable in terms of another; dis- needed for this since the port has only slope of the equation at any point; the new equation also can be four pins. The infrared LEDs on the and find the point where a local mini- played just as it would be in a text back panel are used to transmit or re- mum or maximum occurs. book. One algebraic function that you can't perform is finding the fac- ceive information from another HP tors of a polynomial. You can, how- 48SX or to send information to an in- program and press Enter. The pro- ever, solve quadratic equations. frared printer. gramming language is full- featured The HP 48SX can solve calculus One of the optional accessories for in that you can include such things as problems, too. It does differentia- the HP 48SX is an HP Solve Equa- variables, loops, conditions and tests tion, integration and summations, tion Library Application card. This in your programs. and will also do Taylor's polynomial card, which is about the size of a To send data from one HP 48SX to approximations. However, you may credit card, fits into an expansion another, you must first line up the not always get answers in the form slot inside the calculator. You can get computers back to back along an ar- that you expect. For example, taking to this slot by removing a section of row marked on the face of the calcu- the derivative of x2 with respect to x the back cover. The application card

72 / MODERN ELECTRONICS / May 1990 Say You Saw It In Modern Electronics Make good money in a challenging areer as a security electronics technician even start a profitable new business of your own

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CIRCLE NO. 121 ON tKFE IIVruKMA I MEN I.ARV LEARN `/ in TRUTH CLEANING /MAINTENANCE/REPAIR EARN UP TO $1000 A WEEK,WORKING Fig. 4. The HP 48SX has eight plot types. PART TIME FROM YOUR OWN HOME!

Secrets a very powerful scienti- Revealed! contains an equation library of more the HP 48SX than 300 science and engineering fic calculator, it also advances the NO Special a fi- the art with features like the Tools or equations, a constants library, state of Equipment nance library, a periodic table, la- equation writer and units manage- Needed. beled diagrams, a multiple equation ment. However, it is often difficult to solver and even a game. The way to implement these and other features access the features of the card is by without spending considerable time pressing orange arrow and Library. studying a hefty manual. If you are experienced with scienti- OPPORTUNITY THE MONEY MAKING fic calculators and want to upgrade OF THE 1990'S & Conclusions IF you are able to work with common small hand Comments to a more powerful model, the HP tools, and are familiar with basic electronics (i.e. able to choice. use voltmeter, understand DC electronics) .... Anyone trying to decide between the 48SX is certainly an excellent IF you possess average mechanical ability, and have But if you are a novice in this area, a VCR on which to practice and learn ... then we can HP 48SX and mathematical software teach YOU VCR maintenance and repair! has a few things to the choice is not so clear cut. If you FACT: up to 90% of ALL VCR malfunctions are due to that runs on a PC simple MECHANICAL or ELECTROMECHANICAL consider. First of all, any scientific need a scientific calculator as sophis- breakdowns! to FACT: over 77 million VCRs in use today nationwide! calculator has the twin advantages of ticated as this one, be prepared Average VCR needs service or repair every 12 to 18 frustrat- months! portability and a dedicated user in- spend many hours of often Viejo's 400 PAGE TRAINING MANUAL lover 500 specifically for ening time learning to harness its pow- photos and illustrations) and AWARD -WINNING VIDEO terface designed TRAINING TAPE reveals the SECRETS of VCR mainte- gineering problem solving. This par- er. If you need the functionality of nance and repair - "real- world" information that is NOT available elsewhere! ticular calculator has another advan- the unit but not the frustration, you Also includes all the Into you'll need regarding the considering math BUSINESS -SIDE of running a successful service opera- tage-it can link to a desktop PC (see might be better off tion! for the PC that meets your FREE INFORMATION the sidebar for more information software CALL TOLL -FREE 1. 800. 537 -0589 this feature). And not only is needs but is easier to learn. LE Or write to: about Viejo Publications 3540 Wilshire BL. STE 310 Los Angeles, CA 90010 Dept ME

76 CIRCLE NO. 157 0N FREE INFORMATION CARD Îh HEWLETT 555 Timers (from page57) CI'J PACKARD Deep Discount $274.,' Price HP 488X¡ The two configurations shown in Get yours first-show it off! You know you will buy one sooner or later -why not get yourself up to Fig. 9 are for current -source and cur- speed now, and have some fun to boot? rent -sink operation, just as in the case You'll get it all - big interactive graphics, optional RS -232 seria] interfxe to your PC or MAC, infrared to printer or to another 48SX, for the LEDs above. Make sure that symbolic integrals, derivatives and algebra, statistics, matrices, automatic you use only one of these in a given management of units of measurement -more than 2,100 functions in all. Get it from EduCALC- we're the world's foremost deep discount dealer circuit, of course. for lip calculators since 1976. We have yours in stock, ready to ship quickly. Plus, you'll have our 15 day money back guarantee. Note in Fig. 9 that each relay coil Stock #IIP48SX (Sci Expandable Calculator( List $350 $274.95 is shunted with a 1N4007 rectifier di- Stock #82208, [PC Serial Interface Kill List $59.95 $49.95 ode. Diodes are used for spike sup- Stock #82209A (MAC Serial Interface Kill List $59.95 $49.95 Stock #82211A (Equation Library ROM Crdl List $100 $79.95 pression when the relay coil is de -en- Stock #82214A 132K RAM Cardl List $80 $69.95 ergized. The back -emf generated Stock #82215A I128K RAM Cardl List $250 $194.95 Stock #822408 (Portable Infrared Printer) List when a relay coil deenergizes can be $135 $115.95 Toll -free credit card orders, M -F, 8 to 5 west a high -voltage spike that can destroy coast time - (800)677 -7001 or all hours, all days - (800)633 -2252, ext 359. FAX orders to (714)582 -1445. the 555 and other components in a Or, just tear out this ad and mail it with our name, address and check (UPS $4 circuit. It has a reverse polarity with per order) to EduCALC , 27953 Cabot Road, Laguna Niguel, CA 92677. respect to V + . Thus, the diodes are CIRCLE 50. 168 ON FREE INFORMATION CARIZ normally reverse -biased, except when a large inductive spike from the relay ELECTRON TUBES BUILD YOUR OWN LASER! is received. Keep firmly in mind that OVER 3000 TYPES IN STOCK! New manual reveals latest laser break- Also c.rpactors trar,sh,r mirs throughs and gives complete step -by- these diodes are not optional. typr, and parts for tube rq sprserl step instructions for building 6 kinds of Srnv 5.' 00 Inn 76 Shown in Fig. 10 is a method for real working lasers with easy- t solving a problem that is sometimes parts (sources for ell parts are given ANTIQUE ELECTRONIC SUPPLY including an infrared laser that you can make quickly for encountered with 555 relay drivers under $30' 30-Day Money -Back Guarantee it not completely satisfied but keep the FREE safety deal (above) FIRST and certain other 555 circuits in 688 -M W. ST TEMPE, AZ 65281 bduded with each order. PHONE: 602/894.9503 FAX: 602/894 -0124 Send $8.75 plus $2.75 P1F1 to: which digital pulses or noise spikes Biophysica Inc, 902 -M Weal 36th St, Baltimore, MD 21211 appear. The spikes can get inside the 555 via its OUTPUT pin, where it Double your income! forces the internal digital chip circuitry to reset. The diodes shown pro- Computer maintenance /service vide some crude isolation for the output of the 555. -a $10 billion industry. If you have ever experienced seem- If you are presently servicing office machines or any other electronic equipment, ingly computer repair can double your income. unstable operation from a 555 National research results indicate that computer technicians bill out at double the timer, an unusual occurrence with hourly rate of office machine technicians. this well- behaved chip, first deter- Tech -Sery can put you into computer repair quickly, economically and efficiently and with a complete support program including a proven marketing plan. mine whether the problem is external We provide: pulses coupled through pin 3. If so, RECOGNITION TRAINING the Fig. 10 circuit may well solve the Nationally recognized trademarks and Hands on training: IBM, Compaq, Apple, problem. logos Give you immediate recognition as and compatibles at 3 separate levels: Level 1: 8086.8088 In summing up, remember that the a professional computer repair specialist Based Machines by being a Tech -Sery Authorized Computer DOS System Configuration low -cost 555 provides a variety of Repair Center in your market area. and upgrades Level 2: 80286/80386 Machines, Letter functions at very low cost for it and DOCUMENTATION Quality and Laser Printers any additional components needed We provide manuals, schematics, documen- Level 3: System Networks Configuration, to configure a circuit around it. In tation and advanced diagnostic software. Installation and Repair this article, we have examined a small NEW HARDWARE FINANCING CPU's: IBM Apple, Compaq, and others. Available for qualified businesses. number of different ways to interface Printers: Okidata, Epson, HP Lasers and OVER 125 DEALERS 555 others at huge discounts. WORLDWIDE the ubiquitous timer to the exter- Find out why more and more electronic nal world, at both input and output PARTS & BOARD REPAIR professionals are adding computer repair to ends. Now it is up to you to broaden Single source for parts and board repair. their businesses or starting their own com- 24 -hour express turnaround. puter repair businesses. your use base of this extremely versatile chip, through further study and Call Tech -Sery at (212)967 -1865 now. experimentation. You will be glad tech AurHOR,ZEC DEALER you did. vs THE ser. SERVICING WORLD OF MICROS

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CIRCLE NO. 153 ON FREE INFORMATION CARD You Saw It In Modern Electronics 78 / MODERN ELECTRONICS / May 1990 Say AKE i-800-344-4539 CORPORATION AK. Puerto Rico 218 681.6674 FAX - 218 681 3380 TWX 9103508982 DICI KEY CORP INTEGRATED CIRCUITS INTEGRATED CIRCUITS SILICON TRANSISTORS PANASONIC' SU SERIES DISC CAPACITORS mr ws 41-14401icb3Flc Cpac1W. 5+156 IT r -51:8 :r 015116 71 7400 TTl .1.%1) 71 á1x78 56 095111 71 P115119 74 6310000 ./ r 9 Pan 11I5I434 w71 I,F25 1.61 hw 5+6e9 )0 -sU1 76 Nsu9 35 6 3 1 O00 111376 5 P115112 8 1000 25 75 IOOy ]5 57976 36 P115135 33 27 6 3 152.0 i4479 1500 75 75 35 . 74016 II1539111 10, /4RC00 l3u 70014 35 11153516 10 H u0 1100 6 15 1 AMP SILICON RECTIFIERS 4421 3381 75 75 7406 1 54 CMOS 35 7415365. 13 1116' '. 1011 06316 06213 7 4422 15 11016 35 145366A6 54 le TIP 100 06317 33 06214 7N 6 1 Part 0 4423 6800 83 11056 40 74151614 54 90 1417'. 5 10 220 06316 41 P6215 6 4121 10000 25 83 71066 48 /415361166 67 141471N 10 330 #6319 49 06216 9S 4425 15000 25 % 11010 74153131 66 4470 N0 06320 53 06111 O . n 1416110 i 55 4426 22000 25 94 11096 43 74133166 66. 1U t.160 06321 73 26218 1111751 575 4427 33000 25 94 14004 43 11136)06 111 I1n110r 716 Memory 101.3. 06322 99 116229 10003 50 06 4428 41000 25 1 55 10 3 300 06173 I 16 1 06220 )1100 40 1115966 91 Pus 141790011 S0 Pell Rey 1700n 50 94 4429 63000 25 173 10 4 700 06124 06211 741. 50 011596411 I 76 1. 1429014 60 4471475 ' 000 50 1 01 6430 100000 1 110 10 6 26325 196 06121 25 91 l416y ]5 BIIS97411 I89 ®0 3. 00 1479076 60 1151576 100000 50 1 13 4431 1003 50 86 BIlS98N 189 10 10 000 P6326 2 65 26223 2 IIIN ]5 04790111 71 -. 66W 50 90 4432 15W SO 105 10150W 06327 39 86 I)0 11479014 r 5% CARBON FILM RESISTORS 1001 150 68 4413 2700 50 86 71500 TTl 11. 22.000 06328 5 10 }66 3 ) 1! I 19056 two 100 68 44H 3300 50 86 70 Avtll_N. 1 /I, 174 81/2 W411 16 22 06329 27 r6214 14}]Y 13 Pw1 Pras 1M}0071 2200 100 4435 4700 50 Be 1 50 '- 15 33 06330 28 06225 9 1136 30 113006 33 l61}9075 e 3300 1. 9 146 6800 50 1 36 16 47 06331 33 06226 9. 74374 15 7150 }0 15 161791'5 47.100 I99 4411 10000 50 I 01 710036 1 OS 16 103 06332 7 06227 74314 40 35 I61]97 6140011ñ 146 15000 50 1 01 706/56 471 1 71 16 220 06331 47 06228 74316 40 1,5944 11079:+5 56 4439 11000 50 1 09 35 /4f1C76N 50 1r3x11N 90 If 330 P6314 53 06229 1 74404 41 9054 35 161791': Pm S 1,800 021,16 64 33000 50 1 9 7416456 45 1344404 1 eo 780 06335 02Á 14410 115066 ]5 ..n 033 25 61 47000 SO 1» 55 45 11131115 1Y193" 6N3 151r P 3 R P6131 w 741s11 744090 11 94 7411I1Ó716 51 1110[111 2 14193' 06337 l J10 P6232 NPO NPO 1400 15 PO NPO '446411 94 713105 ]I Ilr' 600 600 NPO 1111015 755 11304 5 60 6330 1 49 262H 70.1174l,11)3 53 I . 44700 n956p ID 350 I}0 )N7.01136 53 143101 600 161306 5 P.. 1 15 P6231 115 50 14506 41 1441734 98 143571 600 11]06t5 06340 I 14 06235 1 h' 11516 41 115200 11 1M108vá 06361 741616N 411 í11.14x 5) 69 50 10 pp 4 04 115116 ,1 7456 74x[116M 111076 /5 1Y330, 16. 15.000 34 74S]6 6 Sl 74545 . 25 10 116343 30 1x Ì0308N 90 7033135 516 7461M 46 7,Ml3lx 06236 46011 14 CI 38M 114 54 11140'á 25 22 P6345 26 1451011 46 5 111 16133745 11:3+5 29 06237 /4)6 7111101364 45 Micro 745516 45 11í90L5 á47 16347 06239 74144 44 14C144 '1 1111717 I9) nS717 s9 4 )4755 745941 45 1533900 . 6i7, 25 100 06317 42 06239 50 ,5655 86 - 74104 48 ,5 25 110 P6318 49 P6240 TANTALUM CAPACITORS ' - LOY410M BW )0 15111 F9 75 06319 51 06741 115e04 4. 15470 95.19: 7416M 14 15: 66 P6242 6 257 1 000 06351 W 06243 hic. O3045 2 2 J4 7411911 04411}4 50 6 750 l DC 1 /151134 50 ,35 o11780.7174 6 2 20 06353 135 06244 1.: 99046 3 3 25 42 )196 33 65 45175 0011164 19 40 25 3.X6 06353 111 06245 t 31 02047 25 54 119364 55 11181054C1 49 1131319 I411 01872411 25 4 100 P6354 2 55 06216 0863 34 0244 696 65 71951 61 1 11111114C1 54 145131M ' 0-216 256800 86355 3 9 1063 42 P2049 10 25 106 074 33 v 1} 1471115AC1 SA 190 ñ10.000 P 6Ts6/ I.j S 15 6 3 50 741 14SI]SM Ii 0911 53 14190531 93 a6319N 35 P6240 22 6 3 60 2057 22 25 Ìóé )151R11 ' IBB 11791}Ct 96 0-1x5 0111111 60 7. 140 35 10 P6358 26 262. H 6 3 72 2053P 25 2 2 7 1451395 85 - .10 7417311 56 1175 1411915C1 96 O 47 6 3 85 213 01 35 744'16 56 00.3 1e 35 21 6359 29 06249 0 131354 60 35 35 6yú3 I 18 2054 0 15 35 27 S SIN 13 0277 +. 3 14116my 114 35 P6351 P6251 100 6 3 187 2056 0 22 35 27 /ISIS34 BS 741491 I WIOCCM 110 35 100 06361 46 06252 15063 390 02156 033 35 21 m 451575 85 1116.194. wgj, 35 220 06363 56 P6I63 22063 785 2051 047 35 21 85 447805 ; 00.. i 14515BIr I 1séCSi yé BI 661606 no 10.366 66 26251 330 603 1058 068 35 28 /1s1616 spy 63 1U sis AIU60) P665 72 P6255 R 7159 1035 31 7;51636 2311 1 P61t11r I 8 62 3 3 10 31 5 35 34 /41534 1 65 401e09 351000 03 250 6] 5'114 63 us 40'1] 15 741566 158 41471109 18 21 ex 35 1.200 71 P6257 10 34 2061 2 2 35 42 74S 710 104 6] 0 meoonrns 165 10741 35 3.300 06368 2 4e 6 1 IO 42 01062 3 3 35 51 741554 60 744624:1'. 1 70 461810 134 P6250 7415/1 60 /1518111 741 7744 110 001811 35 1,700 06]69 311 10 10 50 2063 4 7 35 65 /1511176 1 05 06310 4 15 10 50 X61 6935 90 71161W 75 165 661115 88260 Set of 5 each of the 12 4tanYr3 599 99.10 W 43111w I 70 )1X 7455 22 10 l2 P9366 70 35 9 /41446 75 I e0 00)11B 1 art6o Im r ss the 6LÓ I 10477, 2 75 7431910 4 50 1 0 06150 13 10 W 2066 35 IN )1166 195 661170 3n 1 6 1054} 1 1 O 1451951 I 13 50 1 7 0661 47 10 18 2039 04735 43 I 0 0 O 70 A9)1104 7552404 163 P6311 21 06262 68 10 182 P21. 068 35 43 141166 61 .7N 51 0010105 51414 163 5 WIREWOUND REC. RESISTORS wi7 06312 26 06263 10070 3. 02101 22 35 256 II15N 434040 5 ] 10 01/11106 61 14674311 50 10 10373 29 06764 50 10 6 618 117107 33 35 4 46 350' 414010 11 00/110Ì 170ÿ 110 50 22 P6314 35 P6765 02103 41.35 73.6 145}444 I 720.10 9 63 63 41401[15 44781011 7S0 i10 5033 P6175 41 06266 5 16 20 P267 0100 28 .)y 5 11 195 343401 S 17 5'5 0018109 AUY.0Aems 50 47 0636 5 06267 16 li P2068 0 15 56 30 451545}5]11 90 41401 17 07 4418110 ) S. sod 7r51 515 tot Swan or end W IO' tor 10 05377 479 P62613 3 3 16 P261 0 22 50 30 "+M 315 } 7 50 100 H 7437571 1 30 4M15117 Het e 50.3 Pe 5V 5 wattl .6 the 0171 Ker 3131 191 61330115 /9 50 220 0639 70 P62SV 4 ) 16 11 O 2010 03350 Á 452540 90 41118115 n m es7 97 43410 5 90 50 330 0639 29 0629 6816 50 02071 0 47 50 13 1y 1162104 1 68 4341412 100 117110 1 99 161 1,080 02012 YO PNCM 080 50 4m 06100 6 0627 t0 16 50 069 50 37 1457816 1 61 4341P15 90 4471170 - 3 100 167 01 1000 1661 1 P627 I 15 16 02073 1 50 7+3 90 25 26 90 80 50 % 31 050 7451316 100 41155 1 S 50 P6382 2 06273 2 27 16 02074 1 550 84 111 w .. 1 41 3190 11800 1120 00 2.2. 52 P 7 115}764 39 6 ' 1 70 . ' :.+ 00 3 300 P6183 63 16 I 18 02005 2750 90 1:510 1ti/ : 1151134 I7! 4341 Mwa11644etw Awarbnw94 P2076 /43654 50 4,100 79 6 162 3350 1. 3 7151114 I 05 7 Sr not 112010 63 0 47 1.5.3115 P6214 68 16 3 W P10P7 5750 180 743675 10 65165rar .,.lon.03101n0vO. 7431814 1 95 1 0 P6S16 P6275 6 2209 743646 63 21 935 1454134 440 06357 P6276 2]I.a 1N50y 10 1]1 30 6321 21 6% 7451/]6 4 10 P 6386 26 P6277 ll 754514 50 745471y 4 BO 63 4 7 16389 29 0629 )94513 50 .]1 90 2,617511 180 63 10 6410 34 0619 PANASONIC' V SIMMS 1S451y 50 : S570y í 15 63 22 06391 : P6280 Ì222261 M.1.481781 Fio 194116 Ca..IBW4 30 7455714 l75 1111 10 63 31 O 6392 7 P6281 151914 t 00 74S5>1M 150 63 41 P6393 41 06282 YON. P. 4940N 500 63 100 06391 59 P6263 I n Rescato. Assortments 6g/VAC 1.0 '114 18 y 63 220 06395 78 P6201 RIZO . . 01.6 63 130 P6396 92 #6185 O150 012 50 26 63 19 175#6?867 100041 TTL 015 50 28 ;1711 012 100 72200 63 ' 000 04p6Hi9B2 I 018 50 32 ;1115 015 1. Parr Pose CMOS 63 2200 399 63 P6 5x06 02750 35 P 4116 018 103 50011 37 METAL OXIDE FILM RESISTORS 63 3.100 06400 183 Pen 031 50 35 P47 11 122.100 14150}4 M 1 8 I Wet 100 04) 06401 21 06288 ]} 7111CNi1BN 31.1 *._ 4[006 P 45 033 50 Pol8 027 1W 74130]5 37 10010 06002 21 #6289 '41015 15 14NC470fi 1 64 Now To Order 039 50 19 033 100 7459411 11 Inlerlace 100 22 26 06290 P 4720 TOO '1[016 71 2 06291 057 50 47 0. J10056 3 .33 P9404 9 /40004 45 SSV x511 v9 056 50 51 P1111 047 1. . n, Im17 166405 34 12 )1150920 3i) 1[101 5 088 50 63 04712 7415094 ..1n. 100 10 P606 42 06.3 37 41130 01723 700 11 1 100 22 06477 P6294 iii 74151016 32 4000 CMOS Pricing 6 180 661 1,080 . 21724 082 100 74116 45 100 06108 54 06295 01507ó fé 2 25 74151 17 H 04725 743309 45 100 116109 57 0676 12 50 W 11. 2m 1 $2 UM: 21 91 17 90 56 00 101 50 04726 70112 140379 11 41 /sun 100 I. P6410 82 1677 15 50 95 12 100 257 )á3111y 45 1l IB 50 ÌO 04727 15,100 176 103 rrn 103 P6a11 1 06288 2 65 ISM 120 22 ]6 734síÿ 1 15 70 4000 7150 18 7404116 13 O 051171 900 100 3Á P6412 154 06203 22 50 IW 29 117áá10M1 ]} 754544 27 50 75 2477 22 194 74C13N 65 1. 470 P6413 2 02 766310 I I. 7415114 37 27 103 110749 63 ] 229157 23 I06 1315 5940 10940 >.. 1OW P6614 3 91 33 50 79 394 7115166 17 P473301 )IC766 65 754970 760 06415 39 50 IO H 100 ; 81 115706 31 3,+635 47 50 45 04732 39 1. 22 1131136 160 0417! II R5 10 50 41 50 87 W 150 10 06N6 04733 41. 4 011536 37 /4[1139 160 1.11 06411 56 50 1. 71 /415314 1 Wall Mots 114s.wr 31 74C004 11 *2í7. 160 P6418 45114 33 1462 5. SILICON TRANSISTORS F29.ó 06419 37 PANASONIC B SERIES 7415]60 1] 10 1IC96 I )] 215 1 1. P619 46 1415474 60 160 22 P 11C939 113 582015 earn of 10í4229562V to 75K2 120.6 619 65 /IISS19 45 PI1Irsr0 Ñ hXs 105451 IW 06180 W 74[954 150 1256 Total Pece41 1556 W27 50 OS /415501 4 14C10/11 1111111 ii7 743350 1 . 471 P6181 1 13 1557 0033250 6 65 7 OM 120.99 761055 / 255679 65615 n821,17o IW 1. 741513111 12 74[ 196 ]98 16 P4561 001 50 I 6 4558 0000-50 05 04151444 42 110 ISIN 260 143439 1 75 1289 6.7 0117,12 760 1616263 2 15 P4562 0012 50 4564 0017 50 6 76 1. 7413701 67 7.13411 1w 743440 2 Wall R.. for Á40í004m. 750 10 061M 04563 .1550 1. 4550 0056'50 05 .43700 IO 1E 750 061% 42 )413104 72 1 4561 LGW10 57 401506 760 029 6 7;1554 0018 50 05 6 263111 _106 250 P61W 43 556 0322 50 I 1562 0352. 50 14131101 66 04(166 12550 41 P,r, raí 6 6 71158. 66 0441614 53903 )1 250 i7 43 95292 Ses of odors 62VIO75.7 129.95 250 10 P67 1415904 39 1101614 53901 W 6 1256]4723 119_4, 250 27 06189 QUARTZ CRYSTALS 071á909 SI 04616111 53905 87 2570 51906 5 each.l vanes x in 014 120 99 1 :919 51 8516 2.7 746 16411 ;51961 250 11 P6191 16 ,'.101411 18 MIAs POegRo 7131634 .59000 11 250. 1. 08192 2.1. Case Tc."' 10 111941 45 743176 1% FILM RESISTORS 49032 1 METAL OXIDE 50 10 25193 1015 NCH 10 35 84 m '114F 45 7.101 741 440]] gala.. 1/416.1 450 7 2 K194 1066 NC IB 965 950 74CI7511 W036 450 33 P6195 X046 NCH 396 1300 45., 173 7.0211 :54000 11, 450 47 1 i % x001 NC I9 342 2W 48 74319311 :44113 50 n3 xmt NCH 3 78 31 50 71[19511 .53174 21 50 22 261% 9008 Sc 18 324 27W

. r3 74c7:15 1N1115 O ..cerq 5 200 e,O80 0047 NCH 318 31 SO /N1176 or Á 00 DISC CAPACITORS 0069 NC IB 300 25 50 164106 I n 5070 HC 1 3 ST 50 63 111 W4N Meal 1.1n. Reu,m,r A. 104209 210 Cap./17009. P.w A010 NCH 378 3mí 50 65 P11W 0000 '. 144134 5022 NC 18 1 13 71' 030.06 40. I80/IVI 19 P4I59 1'5000 4. 1440 15 104715 2 3. X005 NCH 280 7950 1O 500 71 P1150 2200050 33 744736 2 3'.. 1, 10q NC 18 162 13,50 65211 each salutes 1 0 0 . o.3 . 840.80 15 500 64 P1I00 H. 31 784231 2 3 . 1011 BE 16 1 62 7350 4.10741 P.rnt 4033 18'500 64 24102 150 500 íl 744735 I ll ,50112 HC 6. 2 00 22 4001 11 500 64 04103 180500 ' V .. 115 Ss 718735 23' RS]% 5 757 6 006.7 1. u5. 11a.99 4auloalv34«.47 27 503 64 P4104 220500 55 SS 2114400 72 NC lx 62 1350 H 500 64 04105 270 SO 0.0 144401 11819 Sean ol values 1006VIO978KV 126.6 N 007 NC 18 55 55 6.7 500 330 50 62 7350 SI 714407 11 101a1 P./.:1 NC 18 13.50 ' 31 '1. 4008 475. 64 01107 390 50. 050 62 45 ]] 246403 21 1120.6 4039 50 500 U 04135 410500 61 0C 18 62 13 58 294410 16 051 NC 18 62 1350 '3 39 0.10 6 SUO 11 P4109 590 500 244896 19, 11C 18 62 30 0401' 82 500 71 P4110 610 5. 245016 PANASONIC' SU SERIES NC IB I371 505 0 95 21 000 15 % P4111 820 503 01 62 115081 1 Mc 78 93 78 4 d4í227 Alvnfrxen FYC11e4t1. CaOa.nws 1142 1500 35 98 04117 TOW 00 n6 62 1350 745011 7e 54 NC IB 7350 34C9135 163 74 P 4741 2206 25 W 04114 50 62 215019 }r Aml loan lav HC 18 62 1350 .,C9104 1045 04144 3300 25 98 04116 ro. 1 Ñ 115110 WV C13 Uwr Xv 03.. Ilv 56 C 18 62 13 50 !7 24091314 60 00 P414á 700 25 P41I7 120 1M I 21 7l IVDC73.11 PM Na 1 Pet Na 1 . 75 785221 NC18 62 1350 .3 7439171 16 01111 150 16 1 V 4 7 0 6e.6 m 45175 1 35 47 +67 PC 18 62 ]I0911M 1 )1 0763, O 11iÌ 10000 6 13 04119 1501K I M 1350 11 1 10 01.117 7409I54 6l0 45276 32 6 3 100 75311. 06201 16 P41. 1520 25 20 P120 20 16 X0711 P 18 90 16 I 6 1X5777 23 ta 01142413 34 X058 NC 18 7355500 6 3 220 P630 07. 06102 21 PI11I 1N 62 t6 71C976r1 6 ]e 140 04149 220W 6 20 11620 30 0.149 34 6 3 310 P634 42 P6103 22 197 0059 0018 62 1350 66 :IC91711 631 53000.25 ]5 P122 33016 60 1a -1]50 ]4 470 P6305 P6204 23 1110 0077 NC III 62 7193l11 631 24152 Ho16 U. 743243 6e L1 30 -4750A 40 63 31 030 06306 U P6206 H 120 11 8060 NC 18 10 15 00 74091711 óów: re áii71 i I 71 I 7415}4911 ll 1 6961 NC IS 30 -4151 30 6 3 2 2. 05101 RI 06716 62 Pé1v 77. .ri HI W . 64 . 73 6 81 . 1 . 74[945414C9411 l . 0 36 ...... ,01 cp 74C947F '22

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CIRCLE S ON FREI. I'. FORMATION CARD SHORTWAVE, ham, scanner radio books. Catalog $1. Tiare Publications, P.O. Box 493ME, Lake Geneva, WI 53147. MORSE Code? No Problem. You can increase your speed, no matter how many times you've failed before. Results guaranteed when BARGAIN HEADQUARTERS! you follow the instructions. PASS Publish- JERROLD TOCOM HAMLIN ing's CW Mental -Block Buster program helps ZENITH SCIENTIFIC ATLANTA you explode mental blocks that hold you back. Oak 11A3SB ONLY $60 6 month warranty! We ship C.O.D.! Based on 40 years of research, the CW Mental - Lowest retailtwholesab prices! Block Buster uses guided meditation, dynamic 6805 MICROCOMPUTER FREE CATALOG: Global Cable Network visualizations, and powerful affirmations to DEVELOPMENT SYSTEM 1032 Irving St. Suite 109 blast through mental blocks. You can do Now its easier than ever to incorporate single chip S.F., CA 94122 microcomputers in your new designs. The MCPM -1 code! That means new bands, more contacts, system allows the IBM PC and compatibles to be ORDER TODAY! 800 -327 -8544 more fun! (This is not a CW practice tape.) used as a complete development system for the cassette ( IK1 I t NO. 159 ON FREE INFORMATION CARD The CW Mental -Block Buster audio Motorola MC68705P3, P5, U3,1J5, R3 and R5 single are only $24.95 ppd. in chip microcomputers. The system Includes a cross and practice booklet program US (NY residents add $1.87 sales tax). assembler program, a simulator /debugger Cable Converters And the and a programming board that connects to a serial (Quantity discounts available for classes.) port. Price = S449.00 VISA and MASTERCARD Descramblers PASS Publishing, P.O. Box 570, Stony accepted. a High Monthly Fee? Brook, NY 11780. fN6/NfVES Why Pay EC Write Call or ((,,r COILABOBAIIYf. INC For FREE Catalog COMPUTERS RR#3, BOX 8C Barton, Vermont 05822 CABLE CONNECTION ENGINEERING Software, PC /MSDOS. Phone (802) 525.3458 FAX (802) 525.3451 1304 E. CHICAGO ST. -SUITE 301 Hobbyists- Students -Engineers. Circuit De- ALGONQUIN, IL 60102 sign $49, PCB Layout $99, Logic Simulation (708) 658.2365 $29, Mathematics $39, Circuit Analysis $29. ('IR('LF NO. 158 ON FREE INFORMATION ('ARD No Illinois Orders Call or Write For Free Catalog. (614) 491- 0832, BSOFT SOFTWARE, 444 Colton CABLE -MATE, INC. Road, Columbus, OH 43207. Are You Tired of Paying SURVEILLANCE Outrageous Fees? LOTTERY Software, Our sophisticated but TELEPHONE easy to use program can make your dream All makes and models of cable This is a normal functioning telephone' come true. IBM PC, COMPATIBLE. $29 shipped within 24 hrs. EXCEPT it has a secret built in monitor money order: POLYWAY BUSINESS equipment Only YOU can call and monitor all conversations. using a check, Quantity discounts. For free secret code, and never be detected' Range Unlimited INC., P.O. BOX 11086, NEW BRUNS- time 6 mOln WnranIv Phone TN Catalog 53.00 catalog send S.A.S.E. to: LISTEN ELECTRONICS. 10.7 ENO. Muskogee. OM 7401 WICK, NJ 08906. Inc., 214 N. Main St., 1. 800. 633 -TAPS Cable -Mate, ABSOLUTELY LOWEST PRICES on com- IL Algonquin, 60102 and accessories- guaran- accepted puters, software C.O.D. orders -TV BOXES teed. Write for free information: SEABIRD, FOR PRICES TODAY!! CABLE CALL 4K Militia Drive, Lexington, MA 02173. 800 -422 -0525 Descramblers Converters (708) 658 -2121 FREE CATALOG Bl'SINFSS OPPOR I-l'`I71E1 No Illinois orders Hours -8:00 am -5:00 pm central time TRANS -WORLD CABLE CO. LEARN to Clean /Repair Fax Machines. , 12062 Southwest 117th Ct., Suite 126 . Huge new market! Earn $85 /hour. No experi- Miami, Florida 33186 ence necessary. Free details call 1- 800 -537- 800 -442 -9333 0589 or write to: Viejo Publications, 3540 Wil- CB TRICKS OF THE TRADE I & II shire Blvd., #310, Dept. FX300, Los Angeles,

Tricks I and Tricks II, plus a free set of CA 90010. plans for CB Super Modulation. COMMUNICATIONS CABLE TV EQUIPMENT Special: $40.00 Zenith Order each book separately for $19.95 ANTENNA SOFTWARE PROGRAM. Cal- Z- KICKER "Throw your super away." Guarantees non-flashing $279.95 C.O.D. Orders Accepted culates antenna lengths for radios, scanners, & each; $229.95 10 or more. Jim 1- 800 -969- toMedicine Man CB CB's. Specify Commodore or IBM. Send 3576. FLPO, Inc., P.O. Box 081426, Racine, P.O. Box 37, Dept. A tl $5.00. Antenna, P.O. Box 321, Rankin, IL WI 53402. Clarksville, AR 72830 60960. (501) 754.2076 CLASSIFIED ADVERTISING ORDER FORM Mail this form with payment to MODERN ELECTRONICS, Classified Dept., 76 N. Broadway, CABLE TV Hicksville, NY 11801. CONVERTERS Name: IN STOCK Street Address: City: State: Zip: Stocking all types of converters. Panasonic, Note that P.O. Box numbers' and telephone numbers must Jerrold, Tocom, Pioneer, Scientific Atlanta, PRINT EACH WORD SEPARATELY. more each (initial Zenith, Oak, Hamlin, Eagle, and others. be counted as two words each. Circle additional words you wish boldfaced at 20% Call or write for FREE CATALOG boldface word is free). Minimum charge is for 15 words. Mon - Fri 10 to 6 Eastern Time

VIDEO -LINK Free Boldface 2 3 4 Enterprises, Inc. 520 Glenbrook Rd. Suite 202 7 8 Stamford, CT 06906 5 6 Orders: 800-622-9022 Catalog & Info: 203-975-7543

In Electronics 80 / MODERN ELECTRONICS / May 1990 Say You Saw It Modern CABLE EQUIPMENT MISCELLANEOUS sew v

CABLE TV SECRETS -the Duda [% publica- ASIAN LADIES want correspondence for tion the cable companies tried aoEas to ban. HBO, friendship, marriage, SUNSHINE INTER- Movie Channel, Showtime, Descramblers, NATIONAL, Dept. TW, Box 5500, Kailua- Converters, etc. Suppliers list included. $8.95. Kona, HI 96745. (808) 325 -7707. Cable Facts, Box 71I -ME, Pataskala, Ohio = ALCOHOL BREATH PE 43062. TESTERS -TEST 71::::::e7N.: %A YOUR BLOOD ALCOHOL CONTENT s BEFORE DRIVING, 2/$5.00 ppd., R. as0t;lc e (':AHLE. J. ,,ses CROWLEY, P.O. BOX 1087, WILLIAMS- TOCOM VIP TEST CHIP. For Models 5503 òt\te° Pa OC VILLE, NY 14231. P VIP and 5507. Unlike any other turn -on, this Kqa\tH t\t9ó16e5"hoos one works! Easily installs in just seconds. ATTRACTIVE ORIENTAL LADIES seek- {p1 a $50.00 each. No Calif. sales. Call (213) ing correspondence, marriage. Professional ó\1dóg p\ 867 -0081. introductions since 1984. Asian Experience, p151dZ ea , 1s e 1a\ Box 1214TZ, Novato, CA 94948. (415) ch b0 c d 'tÓ JERROLD SB -3 substitute. Unmodified units 897- 2742. koka\ \n teaok1a12 in 5 lots only $25.00 each. Modified units óvóce\ee\pK $35.00 ea. in 5 lots. No Calif. sales. Call (213) MAKE $50 /hr working evenings or weekends w0 867-0081. in your own electronics business. Send ot\\eceFçhd for free NEGO facts. MJOI INDUSTRY, Box 531, Bronx, Casse6 p\\ s° GLOBAL CABLE NETWORK 10461. NE NY PNO `e\esh0 - ('ABLE 'IV converter and descrambler auomallcca

CIRCLE NO. 160 ON FREE INFORMATION CARD 81 ADVERTISERS' INDEX NEW PRODUCTS Slide Projector (from page 43) (from page 15) RS# Page # 162 AMC Sales 81 155 ARRL 68 means for monitoring the waveform the control unit might trigger on the 160 All Electronics 81 projector and change a slide. If this Antique Electronic Supply 77 of an external sync signal. B&B Inc 78 A multi -turn time control permits occurs, back off on the setting of the Biophysics Technologies, Inc 77 Dual trimmer potentiometer just a bit. The 165 C&S Sales 15 simple waveform expansion. Cable Connection 80 adjustment for both coarse and fine only loss in doing this will be that the Cable -Mate Inc 80 projector will not switch on at the Cleveland Institute of Elec Coy. Ill control are combined in a single Command Productions 62 knob. Also included are triggered - very bottom of the travel of the slide 147 Consolidated Electronics 10 screen control. 161 Cook's Institute 81 sweep circuitry for stable on- Damark International 63 displays and variable hold -off con- You may be concerned that the 154 Deco Industries 78 projector will not have time to cool 8 Digi -Key Corp 79 168 EduCALC 77 down if it is switched on and off in 159 Global Cable Network 80 normal operation. This is not the Grantham 61 151 Heath Co 51 case, however. In tests with a number 115 ICOM Coy. IN of different slide projectors, no ex- 121 Information Unlimited 76 41 Kenwood Coy. 11 cessive temperature was reached. If Listen Electronics 80 the projector is on for a long period 164 MCM Electronics 7 146 Mouser Electronics 10 of time, the temperature tends to sta- Medicine Man CB 80 bilize after about 4 minutes. If the NRI Schools 13, 75 153 Nu -Tek Electronics 78 projector is used intermittently for PC Boards 78 short periods, it never gets hot Pacific Cable Co., Inc 5 trol for proper triggering on com- 163 Parts Express International 4 enough to reach even this stabilized 167 Smith Design 6 plex- waveform signals. temperature. T.J. Services 69 Features include A and B sweeps 134 TECI 80 Provided the time period is ade- 166 Tech Sery 77 and segment with delayed sweep quate between the end of T2 and the Trans World Cable Co 80 magnification; TV sync coupling; a U.S. Consumer 35 end of T1 in Fig. 5(A) (this can be ad- 156 Ucando 69 variable camera -mount CRT bezel, justed with R16), consecutive slides Video-Link Ent, Inc 80 scale illumination and single sweep 157 Viejo Publications 76 can be shown without the projector Visitect Inc 69 dis- operation for photographing turning off between each slide. If the played waveforms; and Z -axis input N e'd like to see your company listed here too. Contact projector is still running when the Jonathan Kummer at 516.681 -2922 to work out an for blanking or intensified markers. advertising program tailored to suit your needs. slide -type FADER control is opened $1,290. again, it will continue running with- CIRCLE NO. 1320N FREE INFORMATION CARD out a break and maintain the correct Outlet sequence of events. Multiple DC Although the Electronic Control- MFJ Enterprises' (Mississippi State, ler described here was designed spe- MS) Model MFJ -1112 Multiple DC cifically to work with Kodak Ekta- Power Outlet is designed to save graphic slide projectors, almost any by pro- by Be MM, space on a crowded testbench other projector can be controlled j11i2%t it. Even a projector that uses a low - ; 1- '° voltage lamp powered by an internal transformer can be faded in and out Free Product Information with no change in component values Readers can obtain free information on in the circuitry. products advertised by the above com- With a low- voltage, high -wattage panies, as well as for some editorially lamp, the triac specified for Q5 must mentioned products. Simply circle the viding six pairs of heavy -duty color - be bolted to a sizable heat sink, per- appropriate number printed below an coded binding posts for connection haps the metal body of the projector onto the Modern Elec- advertisement to circuits. The device connects di- itself. However, provided a break in tronics "Free Information Service" rectly to any 12 -volt dc power supply the supply to the lamp can be found, card bound into this issue. After filling and includes bypassing to keep r-f will yield control of in your name and address, just mail the the circuit good out of the supply from the dc line out- postpaid card. Your request will be for- the brightness of the lamp and all 13'/2 x 23/4 x warded directly to the advertiser with a let. It measures just other slide functions. mailing label prepared by our reader - 2'/2 inches. $24.95. re- Photos by Teresa Hernandez service department to ensure speedy CIRCLE NO. 133 ON FREE INFORMATION CARD sponse.

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