The best introduction to using PIC Microcontrollers ever writte


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Add Infra-Red remote control to your hifi


Detects static electricity, | THENo.] tracks interference

and live wires, tests

continuity, Capacitors,

diodes and batteries

Innovations - New Technology Update Ingenuity Unlimited - Interface


1.14 metre dia blades, carbon matrix blades, 3 year warranty, 12vdc output, 24v version available, control electronics included, brushless neodymium cubic curve alternator, only two moving parts, maintenance free, simple roof top installation, start up speed 7mph, max output (30mph) 380w. £499 ref AIR4


PORTABLE X RAY MACHINE PLANS Easy to construct plans on a simple and cheap way to build a home X-ray machine! Effective device, X-ray sealed assemblies. can be used for experimental purposes. Not a toy or for minors! £6/set. Ref F/XP1. TELEKINETIC ENHANCER PLANS Mystify and amaze your friends by creating motion with no known apparent means or cause. Uses no electrical or mechanical connections, no special gimmicks yet produces positive motion and effect. Excellent for science projects, magic shows, party demonstrations or serious research & development of this strange and amazing phychic phenomenon.

£4/set Ref F/TKE1.

ELECTRONIC HYPNOSIS PLANS & DATA This data shows several ways to put subjects under your control. Included is a full volume reference text and several construction plans that when assembled can produce highly effective stimuli. This material must be used cautiously. It is for use as entertainment at parties etc only, by those experienced in its use. £15/set. Ref F/EHZ2.

GRAVITY GENERATOR PLANS This unique plan demonstrates asimple electrical phenomena that produces an anti-gravity effect. You can actually build a small mock spaceship out of simple materials and without any visible means- cause it to levitate. £10/set Ref F/GRA1. WORLDS SMALLEST TESLA COIL/LIGHTENING DISPLAY GLOBE PLANS Produces up to 750,000 volts of discharge, experiment with extraordinary HV effects, ‘Plasma in a jar’, St Elmo's fire, Corona, excellent science project or conversation piece.

' £5/set Ref F/BTC1/LGS.

COPPER VAPOUR LASER PLANS Produces 100mw of visible green light. High coherency and spectral quality similar to Argon laser but easier and less costly to build yet far more efficient. This particular design was developed at the Atomic Energy Commision of NEGEV in Israel. £10/set Ref F/CVL1.

VOICE SCRAMBLER PLANS Minature solid state system turns speech sound into indecipherable noise that cannot be understood without a second matching unit. Use on telephone to prevent third party listening and bugging. £6/set Ref F/VS9.

PULSED TV JOKER PLANS Little hand held device utilises pulse techniques that will completely disrupt TV picture and sound! works on FM too! DISCRETION ADVISED. £8/set Ref F/TJ5. BODYHEAT TELESCOPE PLANS Highly directional long range device uses recent technology to detect the presence of living bodies, warm and hot spots, heat leaks etc. Intended for security, law enforcement, research and development, etc. Excellent security device or very interesting science project. £8/set Ref F/BHT1.

BURNING, CUTTING CO2 LASER PLANS Projects an invisible beam of heat capable of burning and melting materials over a considerable distance. This laser is one of the most efficient, converting 10% input power into useful output. Not only is this device a workhorse in welding, cutting and heat processing materials but it is also a likely candidate as an effective directed energy beam weapon against missiles, aircraft, ground-to-ground, etc. Particle beams may very well utilize a laser of this type to blast a channel in the atmosphere for a high energy stream of neutrons or other particles. The device is easily applicable to burning and etching wood, cutting, plastics, textiles etc £12/set Ref F/LC7.

DYNAMO FLASHLIGHT Interesting concept, no batteries needed just squeeze the trigger for instant light apparently even works under water in an emergency although we haven't tried it yet! £6.99 ref SC152

ULTRASONIC BLASTER PLANS Laboratory source of sonic shock waves. Blow holes in metal, produce '‘cold' steam, atomize fiquides. Many cleaning uses for PC boards, jewllery, coins, small parts etc. £6/set Ref F/ULB1.

ANTI DOG FORCE FIELD PLANS Highly effective circuit produces time variable pulses of accoustical energy that dogs cannot tolerate £6/set Ref F/DOG2

LASER BOUNCE LISTENER SYSTEM PLANS Allows you to hear sounds from a premises without gaining access. £12/set Ref F/ LLIST1

PHASOR BLAST WAVE PISTOL SERIES PLANS Handheld, has large transducer and battery capacity with external controls. £6/set Ref F/PSP4

INFINITY TRANSMITTER PLANS Telephone line grabber/ room monitor. The ultimate in home/office security and safety! simple to use! Call your home or office phone, push a secret tone on your telephone to access either: A) On premises sound and voices or B) Existing conversation with break-in capability for emergency messages. £7 Ref F/TELEGRAB.

BUG DETECTOR PLANS is that someone getting the goods on you? Easy to construct device locates any hidden source of radio energy! Sniffs out and finds bugs and other sources of bothersome interference. Detects low, high and UHF frequencies. £5/set Ref F/ BD1.

ELECTROMAGNETIC GUN PLANS Projects a metal object a considerable distance-requires adult supervision £5 ref F/EML2.


sounds and voices, open windows, sound sources in ‘hard to get' or hostile premises. Uses satellite technology to gather distant sounds and focus them to our ultra sensitive electronics. Plans also show an optional wireless link system. £8/set ref F/PM5



BRAND NEW AND, CASED, FROM £99. Works with most modern video's, TV's, Composite monitors, video grabber cards etc

Pal, 1v P-P, composite, 750ohm, 1/3" CCD, 4mm F2.8, 500x582, 12vdc, mounting bracket, auto shutter, 100x50x180mm, 3 months warranty,1 off price £119 ref XEF150, 10 or more £99 ea 100+ £89


Smallest Integrated Radar « Laser Detector


Detects both radar and laser, X, K, superwide KA bands. LED signal strength display Audio and visual alerts, Alert priority, Rear and front facing optical waveguides, Triplecheck verification, city mode, tutorial mode, dark mode, aux jack, volume control. These may be

iegal to use in certain countries.


Superband £149 ref RD2





"phone orders : 01273 203500

FAX 01273 323077 E-mail bull@pavilion.co.uk


DO YOU GROW YOUR OWN? Wehavea fullcolour hydroponics catalogue available containing nutrients, pumps, fittings, enviromental control, light fittings, plants, test equipment etc

Ring for your free copy.

*HEMP SEEDS Pack of 50 seeds plus 60 page growing guide £9.95

*Home office licence required for growing in the uk.

1998 Bull Electrical colour catalogue now available, ring for your free copy!

Free gift!! 100 free ring magnets with any

order over £20, just quote ref ‘Christmas one' to qualify!

Our new 1998 catalogue has worms, get your free copy today!!

Tagged 4aH D nicads (saft) unused Pack of 4 £10 ref DNIC2



One of our top most selling night sights is this Russian TZS4. This sight enable you to see in very tow tight levels, or with the aid of the built in infra red illuminator- in total darkness. In 1/4 moonlight you would spot a man at 150m, in total darkness at 75m. Magnification 2.3x, 240x66x190mm,0.9kg, focusing range 1.5m-infinity, M42 camera mount included, runs on 2xAA batteries, 100mm focal length, 8 deg illuminator divergence, 50hrs continuous (no illuminator) 10hrs with, carryingcase and strap.

TZS4 Nightsight £199 ref BAR61


| = E



The No. 1 Magazine for Electronics Technology and Computer Projects

VOL. 27 No. 3 MARCH 1998

Projects ano Circuits

LIGHTING-UP REMINDER by Bart Trepak 168 Don't be a dim-witted road menace have a brilliant flash of inspiration

and get lit-up on time!

THE HANDY THING by Bill Mooney 174 With this amazing electronic analogue of the Swiss Army Knife,

let the Force reveal itself!

INGENUITY UNLIMITED hosted by Alan Winstanley 181 Fan Failure Monitor; Flame Effect; L.E.D.s as Photocells;

DMM Temperature Probe; Current Monitor for Power Supplies SWITCH-ACTIVATED BURGLAR ALARM by Robert Penfold 187 Have you an opportunist burglar near you? Probably and here’s your opportunity to inexpensively deter his anti-social tendencies

AUDIO SYSTEM REMOTE CONTROLLER by Mark Skeete 22 Adding infra-red remote control facilities to your audio system Is easier

than you might think :

Series and ‘Features

INTERFACE by Robert Penfold 192 Revealing more about PC Ins and Outs, and demonstrating a Simple Transistor Tester in the process

NEW TECHNOLOGY UPDATE by lan Poole 194 Hazardous beryllium oxide is being replaced by the safer aluminium nitride in power semiconductor manufacturing

STRIPBOARDMAGIC REVIEW by Andy Flind 19 Anyone who ever creates their own circuits on stripboard and has a

PC could rapidly reap benefits from this innovative design aid

CIRCUIT SURGERY by Alan Winstanley and lan Bell 201 Teach In ‘98 Back to Basics; Positively Negative; Mega Volts; Tapped Transformer; Ground Down; Current Flow

TEACH-IN ‘98 - An Introduction to Digital Electronics - 5 20 by lan Bell, Rob Miles, Dr Tony Wilkinson, Alan Winstanley

This month: Logic design aids: Boolean algebra; Karnaugh maps;

Arithmetic functions; Encoders and decoders

NET WORK - THE INTERNET PAGE surfed by Alan Winstanley 23 ESR Components Get Kitted Out; The QWERTY Generation; Links

Regulars and Services





EDITORIAL 167 SHOPTALK with David Barrington 170 The essential guide to component buying for EPE projects

INNOVATIONS - Barry Fox highlights technology's leading edge 178 Plus everyday news from the world of electronics

READOUT John Becker addresses general points arising 183 PARTS GALLERY + ELECTRONIC CIRCUITS AND

COMPONENTS CD-ROM 196 BACK ISSUES Did you miss these? 204 ELECTRONICS VIDEOS Our range of educational videos 230 DIRECT BOOK SERVICE 231 A wide range of technical books available by mail order

PRINTED CIRCUIT BOARD SERVICE 234 PCBs for EPE projects some at “knockdown” prices! Plus EPE software

EPE PIC TUTORIAL SUPPLEMENT - 1 by John Becker between pages 200 and 201 © Wimborne Publishing Ltd 1998. Copyright in all By popular demand quite simply the easiest practical introduction to drawings, photographs and articles published in using PIC microcontrollers. This month: assembling the versatile EVERYDAY PRACTICAL ELECTRONICS is fully Tutorial demonstration p.c.b. and your first steps in using it! protected, and reproduction or imitations in

whole or in part are expressly forbidden. ADVERTISERS INDEX 240 EE ERE AE TSB, FL TBE BE YT INES AERIS EN PRE EET RN FS RE OIE PARES: OE MEE OD EOE NERD IEEE ATE LES BEEBE NIE SE SED PGES MRT ETE BIT BEG EASON SEINE AT EAR IIE IB ESS IISA ISS NSS EN PIE 2 SESS NETS SEIS: 1 TEBE APR CG SE TES AE Our April ’98 issue will be published on Friday, 6 Readers Services ® Editorial and Advertisement Departments 167

March 1998. See page 163 for details. Everyday Practical Electronics, March 1998 161

Surplus always wanted for cash!


40Mb HD + 3Mb Ram

industrial grade 12Mhz Hi GRADE 286 systems Made in “the USA to an industrial specification, the system was designed for total relia- bility. The compact case houses the motherboard, PSU and EGA video card with single 5%" 1.2 Mb floppy disk drive & integral 40Mb hard disk drive to the front. Real pal clock with battery backup is provided as standard. Supplied in sr ha condition complete with enhanced keyboard, 640k + 2M DOS 4.01 and 90 DAY Full Guarantee. Read

Order as HIGRADE he. Ay ¥Y¥ £99.00 c«&

Optional Fitted extras: VGA graphics card 1.4Mb 3%" floppy disk drive (instead of 1.2 Mb) Wordperfect 6.0 for Dos - when 3%" FDD option ordered £12. 50 NE2000 Ethernet (thick, thin or twisted) network card £29.00


Limited quantity of this 2nd user, superb small size desktop unit. Fully featured with standard simm connectors 30 & 72 pin. Supplied with ke rd, 4 Mb of RAM, SVGA monitor output, 256k cache and integral 120 Mb IDE drive with single 1.44 Mb 3.5" as Be ey drive. Fully tested and hnokplasesor Fully expandable

Many other options available - call for detalis. $4 99. 00 (E)

Massive purchases of standard 5%" and 3%" drives enables us to present prime product at industry rome low prices! All units (unless Stated) are BRAND NEW or removed trom often brand new equip- ment and are fully tested, aligned and shipped to you with a full 90 day guarantee. Call for over 2000 unlisted drives for spares or repair.

3%" Panasonic JU363/4 720K or equivalent RFE £24.95(B 3%" Mitsubishi MF355C-L. 1.4 Meg. Laptops only £25.95(B 3%" Mitsubishi MF355C-D. 1.4 Meg. Non laptop £18.95(B 5%" Teac FD-55GFR 1.2 Meg (for IBM pc's) RFE £18.95(B 5%" Teac FD-55F-03-U 720K 40/80 (for BBC's etc) RFE £29.95(B 5%" BRAND NEW Mitsubishi MF501B 360K £22.95(B Table top case with inte PSU for HH 5%" Flopp or HD £29.95(B 8” Shugart 800/801 8" SS refurbished & tested £210.00(E 8” Shugart 810 SS HH Brand New £195.00(E 8” Shugart 851 8" double sided refurbished & tested £260.00(E 8" Mitsubishi M2894-63 double sided NEW 95.00(E 8" Mitsubishi M2896-63-02U DS slimline NEW .00(E Dual 8" cased drives with integral power supply 2 Mb £499.00(E 2%" TOSHIBA.(19 mm H ) MK2101MAN 2.16 Gb. New £199.00

2%" TOSH.(12.5 mm H) MK1002MAV 1.1 Gb laptop. New £115.00 2%" to 3%" conversion kit for Pc's, complete with connectors £15.95

3%" FUJI FK-309-26 20mb MFM I/F RFE £59.95 3%" CONNER CP3024 20 mb IDE I/F (or equiv.) RFE £59.95 3%" CONNER CP3044 40mb IDE I/F (or equiv.) RFE £69.00 3%" RODIME RO3057S 45mb SCSI I/F (Mac & Acorn) £69.00 3%" QUANTUM 40S Prodrive 42mb SCSI I/F, New RFE £49.00 3%” WESTERN DIGITAL 850mb IDE I/F New 185.00

5%" MINISCRIBE 3425 20mb MFM I/F (or equiv.) RFE 5%" SEAGATE ST-238R 30 mb RLL I/F Refurb

5%" CDC 94205-51 40mb HH MFM I/F RFE tested £69.95 5%" HP 97548 850 Mb SCSI RFE tested £99.00 5%" HP C3010 2 Gbyte SCSI differential RFE tested £195.00 8" NEC D2246 85 Mb SMD interface. New 199.00

8" FUJITSU M2322K 160Mb SMD I/F RFE tested 8" FUJITSU M2392K 2 Gb SMD I/F RFE tested £345.00 Many other drives in stock - Shiipping on all drives is code (D)

Converts your colour monitor into a QUALITY COLOUR TV!!



The TELEBOX is an attractive fully cased mains icomeed unit, con- taining all electionics ready to plug into a host of video monitors made by makers such as MICROVITEC, ATARI, SANYO, SONY, COMMODORE, PHILIPS, TATUNG, AMSTRAD etc. The composite video output will also plug directly into most video recorders, gat reception of TV channels not normally receivable on most telev sion receivers* (TELEBOX MB). Push button controls on the front panel allow reception of 8 fully tuneable ‘off air’ UHF colour television channels. TELEBOX MB covers virtually all television frequencies VHF and UHF including the HYPERBAND as used by most cable TV operators. A composite video output is located on the rear panel for direct connection to most makes of monitor or desktop computer video systems. For complete compatibility - even for monitors with- out sound - an integral 4 watt audio amplifier and low level Hi Fi audio output are provided as standard.

TELEBOX ST for composite video input type monitors £36.95 TELEBOX STL as ST but fitted with Aes ira speaker £39.50 TELEBOX MB Multiband VHF/UHF/Cab rband tuner £69.95 For overseas PAL versions state 5.5 or 6 mHz sound specification. *For cable / hyperband signal reception Talebox MB should be con- nected to a cable type service. Shipping on all Teleboxe's, code (B)

pe of power magine.Over lies Ex Stock o/ list.

A Ae J every t

supply you can

10,000 Power Sup Call forin




6,000,000 items EX STOCK


One of the highest specification monitors you will ever see - At this price - Don’t miss it!!

Mitsubishi FA3415ETKL 14” SVGA Multisync colour monitor with fine

_ 0.28 dot pitch tube and resolution of 1024 x 768. A

sda hy Rey taal rgd ling oes Et COMBIODONE WMODORE ( EGA, VGA &

‘ean | Fully guaranteed, supplied in tac LENT little used condition. Only £119 © sh al

Tit & Swivel Base £4.75 VGA cable for IBM PC included.

Extemal cables for other types of computers CALL As New - Ex Demo

17" 0.28 SVGA Mitsubishi Diamond Pro monitors

Full multisyne etc. Full 90 day guarantee. £325.00 (E)

Just In - Microvitec 20" VGA (800 x 600 res.) colour monitors. Good SH condition - from £299 - CALL for Info

PHILIPS HCS35 bel style as CM8833) attractively styled 14” colour monitor wit GB and standard composite 15.625 Khz video inputs via poe ART socket and separate phono jacks.

Integral audio power amp and speaker for all audio visual uses.

Will connect direct to Amiga and Atari BBC computers. Ideal for all video monitoring / security applications with direct connection to most colour cameras. High Monel with many features such as a conation tune bt hare CR eo button etc. Good used condition - fully tested - guarant

Dimensions: W14" x H1236" x 15%" D. Only £99

PHILIPS HCS31 Ultra compact 9” colour video monitor with stan- dard composite 15.625 Khz video input via SCART socket. Ideal for all monitoring / security applications. High quality, ex-equipment fully tested & guaranteed (possible minor screen burns). In attrac- tive square black plastic case measuring W10" x H10° x 13%" D.

240 V AC mains powered. Only £79.00 (p)

KME 10” 15M10009 high definition colour monitors with 0.28" dot pitch. Superb clarity and modern styling. . "

Operates from any 15.625 khz sync RGB video 3 3 source, with RGB analog and composite sync #: such as Atari, Commodore Amiga, Acorn # Archimedes & BBC. Measures only 1 Yo" x 12" x Soe

20" 22" and 26" AV SPECIALS

Superbly made UK manufacture. PIL all solid state colour monitors, complete with composite video & optional sound input. Attractive teak style case. Perfect for Schools, Shops, Disco, Clubs, etc.In EXCELLENT little used condition with full 90 day guarantee.

20"...£135 22"...£155 26"....£185 (F)

MITS. se FA3445ETKL 14” Industrial spec SVGA monitors £245 1kW to 400 kW - 400 Hz 3 phase power sources - ex stock £POA IBM 8230 Type 1, Token ring base unit driver malas Kerr RA200 Audio frequency response analyser 53F5501 Token Ring ICS 20 port lobe modules

IBM MAU Token ring distribution panel 8228-23-5050N £95 AIM 501 Low distortion Oscillator 9Hz to 330Khz, IEEE £550 Trend DSA 274 Data Analyser with G703(2M) 64 i/o £POA

Marconi 6310 Programmable 2 to 22 GHz sweep generator HP1650B Logic Analyser Vs

HP3781A Pattem generator & HP3782A Error Detector £POA HP6621A Dual Programmable GPIB PSU 0-7 V 160 watts £1800 HP6264 Rack mount variable 0-20V @ 20A metered PSU £675 HP54121A DC to 22 GHz four channel test set £POA HP7580A A1 8 pen HPGL high speed drum plotter £1850 F&B Wardrobe size, insurance spec 1 hour rated fire safe £650 EG+G Brookdeal 95035C Precision lock in amp £650 View Eng. Mod 1200 computerised inspection system £POA Sony DXC-3000A High quality CCD colour TV camera £1100 CSZ VERY Large 3 cavity thermal shock chamber £POA Philips PW1730/10 XRAY generator with accessories £POA Keithle ri 590 CV capacitor / voltage analyser £POA Racal ICR40 dual 40 channel voice recorder system £3750 Fiskers 45KVA 3 ph On Line UPS - New batteries £9500 ICi R5030UV34 Cleanline ultrasonic cleaning system £POA Mann Tally MT645 bye speed line printer £2200 intel SBC 486/133SE Multibus 486 system. 8Mb Ram £945 Intel SBC 486/125C08 Enhanced Multibus (MSA) NEW £1

Zeta 3220-05 re 4 pen HPGL fast drum plotters £1150 Nikon HFX-11 sel ol exposure control unit £1450 Motorola VME 6 Beaice & Components List. SAE / CALL £POA

Trio 0-18 vdc anaar. metered 30 amp bench PSU. New £550

Fujitsu M3041R 600 LPM band printer £1950 Fujitsu M3041D 600 LPM printer with network interface £1250 Perkin Elmer 2998 Infrared spectrophotometer £500 Perkin Elmer 597 Infrared s otometer £3500

hf Electronics 1035 TELETEXT ing Margin Meter £3750 re htBand 60 output high spec 2u rack mount Video VDA's £495 onic SD 150H 18 channel digital Hybrid chart recorder £1995 Taylor Hobson Tallysurf amplifier / recorder £750 . tem Video 1152 PAL waveform monitor esuee mans K4400 64Kb to 140Mb demux analyser

Surplus always wanted for cash!

Superb quality 6 foot 40U Virtually New, Ultra Smart

Less than Half Price!

Top pg 19" rack cabinets made in UK by Optima Enclosures Ltd. Units feature designer, smoked acrylic lockable front door, full height lockable half louvered back door and louvered removable side panels. Fully adjustable internal fixing struts, ready punched for any configuration of equipment mounting plus ready mounted integral 12 way 13 amp ; socket switched mains distribution strip make these racks some of the most versatile we have ever sold. Racks may be stacked side by side and therefore require only two side panels to stand singly or in multiple bays. Overall dimensions are: 77%" H x 32%" D x 22" W. Order as: OPT Rack 1 Complete with removable side panels. £345.00 (G) OPT Rack 2 Rack, Less side panels £245.00 (G)

32U - High Quality - All steel RakCab

Made by Eurocraft Enclosures Ltd to the highest possible spec, rack features all steel construction with removable side, front and back doors. Front and back doors are _<@ hinged for easy access and all are lockable with << five secure 5 lever barrel locks. The front door £& is constructed of double walled steel with a ‘designer style’ smoked acrylic front panel to § enable status indicators to be seen through the abet yet remain unobtrusive. Internally the rack eatures fully slotted reinforced vertical fixin members to take the heaviest of 19” rac equipment. The two movable vertical fixing struts (extras available) are cc punched for standard E& ‘cage nuts’. A mains distribution panel internal- ly mounted to the bottom rear, provides 8 x IEC 3 pin Euro sockets and 1 x 13 amp 3 pin switched “SicecF utility socket. Overall ventilation is provided by “Spe fully louvered back door and double skinned top section “™ with top and side louvres. The top panel may be removed for fitting of integral fans to the sub plate etc. Other features include: fitted castors and floor levelers, prepunched utility panel at lower rear for cable / connector access etc. Supplied in excellent, slightly used condition with keys. Colour Royal blue. External dimensions mm=1625H x 635D x 603 W. ( 64” H x 25” D x 23%” W )

Sold at LESS than a third of makers price !!

A superb buy at only £245.00 «@ 42U version of the above only £345 - CALL

A special bulk purchase from a cancelled export order brings you the most amazing savings on these ultra high spec 12v DC 14 Ah rechargeable batteries. Made by Hawker Energy Ltd, type SBS15 featuring pure lead plates which offer a far superior she & teed 15 year service life. Fully BT & BS6290 approved. Freee. BRAND NEW and boxed. Dimensions 200 wide, 137 high

M6 bolt terminals. Fully guaranteed. Current makers at bt over $70

each!Qur Price £35 each ~ or 4 for £99

Save ££££'s by choosing your next relay from our Massive stocks covering types such as - Military, Octal, Cradle, Hermetically Sealed, Contactors, Time Delay, Reed, Mercu Wetted, Solid State, ’Printed Circuit Mounting, CALL US WITH YOUR NEEDS. Many obsolete types from stock. Save ££££'s

INTEL ‘ABOVE' Memory Expansion Board. Full length PC-XT and PC-AT compatible card with 2 Mbytes of memory on board. Card is fully selectable for Expanded or Extended (286 abe and above) memory. Full data and driver disks supe eas ed. RFE Full ihe tested and guaranteed. Windows compatible.

Half length 8 bit memory upgrade cards for PC AT XT fata memory either 256k or 512k in fm 64k steps. May ai be used to fill

in RAM above 640k DOS limit. Complete with dat Order as: XT RAM UG. 256k. £34.95 or512k £39. 95 SIMM 1 MB x9 SIMM 9 chip 120ns Only £8.50 1MBx9 SIMM3chip 80ns £10.50 or 70ns £11.9 1MBx9 SIMM9chip80ns £10.50 or 70ns £11.75 Only £35.00

4 MB 70 ns 72 pin SIMM_-with parity- INTEL 486-DX33 CPU £19.95 INTEL 486-DxX66 CPU £59.00 FULL RANGE OF CO-PROCESSOR'S EX STOCK - CALL FOR £££ MOTOROLA 25 Mhz 68040 (XC68040RC25M) CPU'S £59.00

shipping charges for RAM / CPU upgrades is code B

NT4 WorkStation, complete with service pack 3 and Rees OEM packaged.

ecial Price ONLY £99.00 Microsoft - wae lows for Workgroups 3.11 & DOS 6.22. Supplied on 3%" disks with license & documentation documentation. £39.95 DOS 5.0 on 3%" disks with concise books c/w QBasic . £14.95 Wordperfect 6 for DOS supplied on 3%" disks with manual £24.95

shipping charges for software is code B

Visit our London shop for. q full range of Test Equipment and other bargains



- Open Mon - Fri 9.00 - 5:30

4 Dept PE , 32 Biggin Way

° Upper Norwood LONDON SE19 3XF

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Universities and Local Authorities - subject to 10 da 'A)=£3.00, (A1 ee mee LA | 26, |S tia (D)}=£12.00, 0 (E15 0, ar 1800, 6, (GALL. Aow approx § days Sippy - aster Roe CALL eee ee Ani, Fenon


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Visit our web site www.distel.co.uk email admin @distel.co.uk


FAX 0181 679 1927

Minimum order £10. Bona Fide account orders accepted

prices / specifications without prior notice. ies hee Display Electronics 1997. EOL 0B



This simple to build power supply unit will provide a single regulated output of 2 volts to 20 volts at 250mA, or it can be switched to provide a dual

supply, suitable for most i.c. experimentation and testing, of 1 volt to 10 volts on either side of earth. This dual supply automatically tracks each side to the other, so that both positive and negative output rails keep in step.


Most of us have had an idea for an invention at some time or another but, unlike the writer (whose words are automatically copyrighted), the would-be inventor must take steps to protect his idea with a patent. Each year around 20,000 patents are taken out by UK residents and of these around 4,000 are from individual inventors rather than businesses and universities. However, before you dash off to the Patent Office with a sheaf of diagrams, it might be wise to check if your idea is patentable at all and on the necessary steps and likely costs of the process. This article explains it all.


Certain types of thermoplastics exhibit piezoelectric properties and these materials can be formed into sheets, thin films or cables. In this article we take a look at piezoelectric cable and show how it can easily be used in a variety of applications by the hobbyist.

The article also provides full constructional details for two simple projects: A Distributed Microphone which uses the cable taped to a window pane, piano soundboard, etc., as a simple acoustic transducer, plus an amplifier and headphones. And a Vibration Alarm, where the cable can be clipped to a fence to detect intruders, or used for door or window security, vehicle detection, etc.


A PIC controlled radio control meter for testing RC transmitters, receivers and servos.

The transmitter frequency, number of channels, frame time and individual channel pulse widths of up to eight channels can be displayed simply by holding the RC transmitter close to the unit. The RC-METER transmitter pulse detector system will only detect pulse data from radio control transmitters using 100 per cent amplitude modulation. However, the frequency readout will operate as long as at least 4ms of transmitted signal is detected, so it can still be used with the more modern FM transmitters.

By connecting a flying lead from one of the radio control receiver’s channel outputs to the RC-METER connector, the meter can display the received pulse width and frame time. The meter can also produce a servo drive signal, mimicking the output of a receiver.




Everyday Practical Electronics, March 1998






- List 5

One item only per pack unless otherwise stated. TEST PRODS FOR MULTIMETERS with 4mm sockets. Good length very flexible lead, Order Ref: D86.

8 OHM PM SPEAKERS, size 8" x 4", pack of 2. These may be slightly rusty and that is why they are so cheap, but are electrically OK, Order Ref: D102.

PAXOLIN PANELS, size 6"x6", approximately 1/16" thick, pack of 2, Order Ref: D103.

13A SOCKET, virtually unbreakable, ideal for trailing lead, Order Ref: D95.

PIEZO BUZZER with electronic sounder circuit, 3V to 9V d.c. operated, Order Ref: D76.

DITTO but without internal electronics, pack of 2, Order Ref: D75.

LUMINOUS ROCKER SWITCH, approximately 30mm sq, pack of 2, Order Ref: D64.

ROTARY SWITCH, 9-pole 6-way, small size and 1%" spindle, pack of 2, Order Ref: D54.

FERRITE RODS, 7" with coils for Long and Medium waves, pack of 2.

DITTO but without the coils, pack of 3.

SLIDE SWITCHES, SPDT, pack of 20, Order Ref: D50. MAINS DP ROTARY SWITCH with 1%" contro! spindle, pack of 5, Order Ref: D49.

ELECTROLYTIC CAP, 800,:F at 6-4V, pack of 20, Order Ref: D48.

ELECTROLYTIC CAP, 1000 + 1000uF 12V, pack of 10, Order Ref: D47.

MINI RELAY with 5V coil, size only 26mmx 19mm x 11mm, has 2 sets changeover contacts, Order Ref: D42. MAINS SUPPRESSOR CAPS, 0:-1,.F 250V a.c., pack of 10, Order Ref: 1050.

TELESCOPIC AERIAL, chrome plated, extendable and folds over for improved FM reception, Order Ref: 1051. MES LAMPHOLDERS, slide onto 1%" tag, pack of 10, Order Ref: 1054.

PAX TUBING, '%" internal diameter, pack of 2, 12" lengths, Order Ref: 1056.

ULTRA THIN DRILLS, 0-4mm, pack of 10, Order Ref: 1042.

20A TOGGLE SWITCHES, centre off, part spring con- trolled, will stay on when pushed up but will spring back when pushed down, pack of 2, Order Ref: 1043.

HALL EFFECT DEVICES, mounted on small heatsink, pack of 2, Order Ref: 1022.

12V POLARISED RELAY, two changeover contacts, Or- der Ref: 1032.

PAXOLIN PANEL, 12" x 12", 1/16" thick, Order Ref: 1033. MINI POTTED TRANSFORMER, only 1:5VA 15V-0V- 15V or 30V, Order Ref: 964.

ELECTROLYTIC CAP, 32..F at 350V and 50uF section at 25V, in alulminium can for upright mounting, pack of 2, Order Ref: 995.

PRE-SET POTS, 1 megohm, pack of 5, Order Ref: 998. WHITE PROJECT BOX with rocker switch in top left-hand side, size 78mm x 115mm x 35mm, unprinted, Order Ref: 1006.

6V SOLENOID, good strong pull but quite small, pack of 2, Order Ref: 1012.

FIGURE-8 MAINS FLEX, also makes good speaker lead, 15m, Order Ref: 1014.

HIGH CURRENT RELAY, 24V ac. or 12V dc., 3 changeover contacts, Order Ref: 1016.

LOUDSPEAKER, 8 ohm 5W, 3:7" round, Order Ref: 962. NEON PILOT LIGHTS, oblong for front panel mounting, with internal resistor for normal mains operation, pack of 4, Order Ref: 970.

3-5MM JACK PLUGS, pack of 10, Order Ref: 975. WANDER PLUGS, pack of 10, Order Ref: 986.

PSU, mains operated, two outputs, one 9-5V at 550mA and the other 15V at 150mA, Order Ref: 988.

ANOTHER PSU, mains operated, output 15V ac. at 320mA, Order Ref: 989.

PHOTOCELLS, silicon chip type, pack of 4, Order Ref: 939.

LOUDSPEAKER, 5" 4ohm 5W rating, Order Ref: 946. 230V ROD ELEMENTS, 500W terminal ended, 10" long, pack of 2, Order Ref: 943.

LOUDSPEAKER, 7" x5", 4ohm 5W, Order Ref: 949. LOUDSPEAKER, 4" circular, 6ohm 3W, pack of 2, Order Ref: 951.

FERRITE POT CORES, 30mm x 15mm x 25mm, match- ing pair, Order Ref: 901.

PAXOLIN PANEL, 8’ x 3% with electrolytics, 250u.F and 100,F, Order Ref: 905.

CAR SOCKET PLUG with PCB compartment, Order Ref: 917.

4-CORE FLEX suitable for telephone extensions, 10m, Order Ref: 918.

VERO OFF-CUTS, approximately 30 square inches of useful sizes, Order Ref: 927.

PROJECT CASE, 95mm x 66mm x 23mm with removal lid held by four screws, pack of 2, Order Ref: 876. SOLENOIDS, 12V to 24V, will push or pull, pack of 2, Order Ref: 877.


2M MAINS LEAD, 3-core with instrument plug moulded on, Order Ref: 879.

TELESCOPIC AERIAL, chrome plated, extendable, pack of 2, Order Ref: 884.

MICROPHONE, dynamic with normal body for handhold- ing, Order Ref: 885.

CROCODILE CLIPS, superior quality flex, can be attached without soldering, 5 each red and black, Order Ref: 886. BATTERY CONNECTOR FOR PP3, superior quality, pack of 4, Order Ref: 887.

LIGHTWEIGHT STEREO HEADPHONES, Order Ref: 898. PRESETS, 470 ohm and 220k, mounted on single panel, pack of 10, Order Ref: 849.

THERMOSTAT for ovens with 14" spindle to take control knob, Order Ref: 857.

12V-0V-12V 10W MAINS TRANSFORMER, Order Ref: 811.

18V-0V-18V 10W MAINS TRANSFORMER, Order Ref: 813.

AIR-SPACED TRIMMER CAPS, 2pF to 20pF, pack of 2, Order Ref: 818.

AMPLIFIER, 9V or 12V operated Mullard 1153, Order Ref: 823.

2 CIRCUIT MICROSWITCHES, pack of 4, Order Ref: 825. LARGE SIZE MICROSWITCHES, (20mm x 6mm x 10mm), changeover contacts, pack of 2, Order Ref: 826.

MAINS VOLTAGE PUSHSWITCH with white dolly, though panel mounting by hexagonal nut.

POINTER KNOB for spindle which is just under 1%", like most thermostats, pack of 4, Order Ref: 833.


All with 220V/240V primary winding OV-30V + 0V-30V at 120VA, would give you 30V at 4A or 60V at 2A, price £8. Order Ref: 8PG2. OV-110V + OV-110V at 120VA would give you 110V at just over 1A or 220V at 1/2A, price £8, Order Ref: 8PG3. OV-35V + OV-35V at 150VA would give you 35V at 4A or 70V at 2A. Price £8. Order Ref: 8PG9. OV-35V + OV-35V at 220VA would give you 35V at 6%2A or 70V at 3%4A, price £9, Order Ref: 9PG4. OV-110V + OV-110V at 220VA would give you 110V at 2A or 220V at 1A, price £10, Order Ref: 10PG5. OV-45V + OV-45V at 500VA would give you 45V at 11A or 90V at 5V2A, price £20, Order Ref: 20PG7. OV-110V + OV-110V at 500VA would give you 110V at 5A or 220V at nearly 3A, price £25, Order Ref: 25PG8.


5V 45A, £20, Order Ref: 20P16.

6V 1A, 2 for £1, Order Ref: 9.

8V 1A, £1, Order Ref: 212.

QV A, 2 for £1, Order Ref: 266.

9V 1A, £1, Order Ref: 236.

9V 3A, £2, Order Ref: 2P408.

10V 1A, £1, Order Ref: 492.

12V “A, 2 for £1, Order Ref: 10.

12V 1A, £1, Order Ref: 436.

12V 1A, £1.50, Order Ref: 1.5P41.

12V 2A, £2, Order Ref: 2P337.

12V 3A, £3, Order Ref: 3P181.

15V 1A, £1, Order Ref: 267.

17V 1A, £1, Order Ref: 492.

18V 1%A, £1, Order Ref: 491.

20V 4A, £3, Order Ref: 3P106.

24V V2A, £1, Order Ref: 337.

24V 1A, £2, Order Ref: 2P413.

24V 1A, £2.50, Order Ref: 2.5P15.

25V 10A, £20, Order Ref: 20P33.

28V 2A, £4, Order Ref: 4P24.

30V 25VA, £2.50, Order Ref: 2.5P25. 40V 2A, £3, Order Ref: 3P107.

43V 3A, £5, Order Ref: 5P262.

50V 2A fully shrouded, £5, Order Ref: 5P210. 50V 15A, £20, Order Ref: 20P2.

675V 100mA, £5, Order Ref: 5P166.

4kV 2mA, £5, Order Ref: 5P 139. 6V-0V-6V 5VA, 2 for £1, Order Ref: 612. 6V-OV-6V 10VA, £1, Order Ref: 281. 7°5V-0V-7-5V 8VA, £1, Order Ref: D104. 7-5V-0V-7-5V 50VA, £4, Order Ref: 4P98. 8V-0V-8V 8VA, £1, Order Ref: 212. 12V-0V-12V 3VA, £1, Order Ref: 636. 12V-0V-12V 6VA, £1, Order Ref: 811. 12V-0V-12V 30VA, £2.50, Order Ref: 2.5P15. 15V-0V-15V 1VA, £1, Order Ref: 937. 15V-OV-15V 15VA, £2, Order Ref: 2P68. 15V-OV-15V 25VA, £2.50, Order Ref: 2.5P24. 18V-O0V-18V 10VA, £1, Order Ref: 813. 20V-0V-20V 10VA, £1, Order Ref: 812. 20V-0V-20V 10VA, £2, Order Ref: 2P85. 20V-0V-20V 20VA, £2, Order Ref: 2P138. 20V-0V-20V 40VA, £3, Order Ref: 3P205. 20V-0V-20V 80VA, £4, Order Ref: 4P36. 25V-0V-25V 40VA, £3, Order Ref: 3P206. 36V-0V-36V 20VA, £2, Order Ref: 2P156.


15VA gives 1V, 7V, 8V, 9V or 10V, £1, Order Ref: 744. 38V-0V-38V 150VA with regulator winding, £10, Order Ref: 10P36.

230V-115V auto transformer, 10VA, £1, Order Ref: 822. 230V-115V auto transformer, 1kVA, £20, Order Ref: 20P29.

230V-115V auto transformer, 300VA, can be made from our Ref: 4P97. This is a big mains transformer but it has a 115V tapping on its primary, £4.

Everyday Practical Electronics, March 1998


Two available. The first is a 10" 4 ohm with a power rating of 250W music and normal 150W. Has a very heavy mag- net and is beautifully made and finished by Challenger. Normal selling price for this is £55+VAT, you can buy at £29 including VAT and carriage, Order Ref: 29P7.

The second one is a 8" 4 ohm, 200W music, 100W normal. Again by Challenger, price £18, Order Ref: 18P9. Incidentally, as these are so heavy, if you collect, then you make a saving of £2 on the 10" and £1.50 on the 8".


2" round 50 ohm coil YAW speaker, pack of 2, £1, Order Ref: 908.

2%" 8 ohm, pack of 2, £1, Order Ref: 454.

2%" 35 ohm, pack of 2, £1, Order Ref: 514.

32" 8 ohm, pack of 2, £1, Order Ref: 682.

5" 4 ohm, pack of 2, £1, Order Ref: 136.