PRACTICAL ELECTRONICS February 1987

CONSTRUCTIONAL PROJECTS

PE HI STAR by Mike Delaney 14

A power supply is essential to every electronics work bench. This one is as good as any home-constructed instrument and better than most.

THE PE 30 PLUS 30 PART ONE by Graham Nalty 42

Build a stereo hi-fi amplifier with exceptional sound quality for less than any other amplifier of similar specification. This is certainly one of the best hi-fi amps ever to appear in PE.

ULTRASONIC RANGER by The Prof 24

Another great experimental electronics project which uses ultrasonics for measurement purposes. This project will be developed further next month.

PE PROMENADER Part Three by Mike Delaney 34

The final part in this multi-channel programmable display unit.

SPECIAL FEATURES

DESIGN - LOW DROP-OUT POWER SUPPLIES by B.J. Frost 20

A look at how modern components can be used to make a battery-powered supply for project testing and development work.

TECHNOLOGY - LIQUID CRYSTAL DISPLAYS by R.A. Penfold 48

L.c.d.s are now used in many everyday (and not so everyday) applications. This feature takes a look at some of these applications and how they work.

TECHNOLOGY- MICROWAVES Part Two by Andrew Armstrong 52

More applications of Microwave technology.

REVIEW- PE 30 PLUS 30 by R.A. Penfold 44

An independent review ofthe PE 30 plus 30 showed that this project certainly lives up to our expectations and the authors claims.

REVIEW - RED BOXES by Ray Stuart 40

The computer add-ons which can be used for a variety of home-control applications, particularly those of security.

STE Part Three by Richard Whitlock 28

Final details of the 8-bit industry standard microprocessor bus.

REGULAR FEATURES

EXPERIMENTAL ELECTRONICS by The Prof 24

This month the Prof looks at ultrasonics in measurement applications.

MICROFORUM by J. Nolan 55

This month wetake a look at a project which slows down the Beeb.

NEWS AND MARKET PLACE 4

News, views and new products from the world of electronics plus: countdown, catalogue casebook and firm contact.

PCB SERVICE 60

BAZAAR 47

SPACEWATCH AND THE SKY THIS MONTH by Dr. Patrick Moore ORE 46

THE LEADING EDGE by Barry Fox 8

INDUSTRY NOTEBOOK by Tom Ivall 57

PRACTICAL ELECTRONICS MARCH 1987

CONSTRUCTIONAL PROJECTS

ULTRASONIC TAPE MEASURE by The Prof 20

The ultrasonic range finding discussed in last months Experimental Electronics forms the basis for an ultrasound devicewhich measures medium distancesto a resolution of 1 centimetre.

MICRO TUNER by John M.H. Becker 25

A very accurate computer controlled frequency counter which, as well as general measuring applications, has been optimised fortuning musical instruments. The basic design works with the C64, BBC and PET computers, but can be adapted for use with other micros.

TELEPHONE BELL REPEATER by Giles Read 35

An adaptable project to relay the sound of the phone ringing to the place you want to hear it.

FIBRE OPTIC LIGHT PEN by R.A. Penfold 36

The use of photodiodes and phototransistors in light pens limits their angle of view. This design uses a fibre optic sensor for higher accuracy.

EXPERIMENTAL ELECTRONICS by The Prof 12

Although it is no longer front page news, four channel 'surround sound' has a lot to recommend it. The author looks at alternative ways of adapting stereo to four channels, and describes a fourchannel enhancer in detail.

THE PE 30 PLUS 30 PART TWO by Graham Nalty 48

Continuing last month's high quality, low cost stereo amplifier design with second p.c.b.

SPECIAL FEATURES DC MOTORS by Brian Brooks 52

Direct current motors havea long historyand have been built and applied in a thousand different ways. This feature looks at some of them.

TECHNOLOGY - SURFACE WAVE ACOUSTIC DEVICES by Andrew Armstrong 40

Several types of piezoelectric crystals can be excited electrically to produce waves across their surface. The wave in turn can generate an electric signal. This property has some unique applications.

REGULAR FEATURES MICROFORUM by Simon A.J. Winder 34

An interface for the BBC B which drives eight dynamic RAMs to provide a memory expansion.

NEWS AND MARKET PLACE 4

News, views and new products from the world of electronics plus: countdown, catalogue casebook and firm contact.

PCB SERVICE 60

BAZAAR 54

SPACEWATCH AND THE SKY THIS MONTH by Dr. Patrick Moore OBE 46

THE LEADING EDGE by Barry Fox 8

INDUSTRY NOTEBOOK by Tom Wall 57  

PRACTICAL ELECTRONICS APRIL 1987

CONSTRUCTIONAL PROJECTS

PE VIGILANTE CAR ALARM by Mike Delaney 20

Keep your car alert to intruders-build a box to fox them!

SWITCH MODE POWER SUPPLIES by Robert Penfold 34

Three practical circuits illustrating the principles discussed in the SMPSU Design feature.

EXPERIMENTAL ELECTRONICS by the Prof 12

Inductive Loops. Ring the changes for your mobiles remote control them via a cable loop.

THE PE 30 PLUS 30 PART THREE by Graham Nalty 48

Concluding this high quality stereo amplifier design.

SPECIAL FEATURES DESIGN - SMPSUS by Robert Penfold 26

Familiarity with subject names does not mean that they are understood. This article clarifies one such area Switch Mode Power Supplies.

TECHNOLOGY - SENSORS by the Prof 40

For data to be acted upon, it must first be detected. Sensors are a vital link in many control and measurement applications.

DC MOTORS by Brian Brooks 52

During their history, directcurrent motors have been built and applied in countless different ways. Part two of this feature looks at more of them.

REGULAR FEATURES

MICROFORUM by Stephen Burkitt 44

The Amstrad is ideally suited to Eprom programming control. Here is a choice of two hardware interfaces.

NEWS AND MARKET PLACE 4

News, views and new products from the world of electronics, plus countdown, catalogue casebook, firm contact and chipcount.

PCB SERVICE - professional PCBs for PE Projects 60

TRACK CENTRE - the PCB track layout pages 32

BAZAAR - readers' Have and Have-not marketplace 62

BINARY CHOP - a powerful mental logic tester 33

SPACE WATCH AND THE SKY THIS MONTH by Dr. Patrick Moore OBE 46

THE LEADING EDGE by Barry Fox 8

INDUSTRY NOTEBOOK by Tom Ivall 57

PE VOL 23 No. 10 PRACTlCAL ELECTRONICS OCTOBER 1987

CONSTRUCTIONAL PROJECTS

GUITAR TO SYNTH INTERFACE by Rober Penfold 12

Don't let your guitar fret - it too can play an orchestra. Plug in, pluck on, and Hallé-lujah!

TEACHER LOCKER by Tim Pike 35

Continuing the series of articles for G.C.S.E. students by decoding the logic behind a digitally gated lock.

DUAL POWER SUPPLY by David Silvester 42

Outputs at ±15V, up to 1.5A, foldback current limiting and cross linked stabilisation. Power for the coarse or fine workshop.

EPROM PROGRAMMER by Malcolm Harvey 48

Computer controlled 4K data transfer and checking via a single 8-bit port, aided by a multioption menu and location selector.

SPECIAL FEATURES

EDUCATIONALLY PRODUCTIVE a selection of reports 7

Products, events and news of special interest to those on both sides of the classroom.

PROGRAMMABLE LOGIC DEVICES by Chris Kelly 21

PLDs turn design dreams into speedy hardware reality. Using conceptual logic, a computer and a device akin to an eprom, the technology offers other benefits as well.

CLICK ELIMINATORS by the Prof 27

Using circuits more broadly known as pulse blankers, unwanted noise can be filtered from radio receivers, scratched records, and other spiked sources.

REGULAR FEATURES

EDITORIAL - An Exclusive Technology? 9

LEADING EDGE by Barry Fox - Brief Mapping Problems 8

SPACEWATCH by Dr. Patrick Moore OBE - Extra-Solar Planets 46

INDUSTRY NOTEBOOK by Tom Ivall - Electronics in Democracy. 57

MARKETPLACE - what's new, where and when 4

TRACE CENTRE - the PCB track layout pages 32

PCB SERVICE - professional PCBs for PE Projects 60

PROJECT ASSEMBLY - a guide to easy building 61

CHIPCHOP a technical logic research analyser 33

READERS' LEITERS and a few answers 54

BAZAAR - Readers' FREE advertising service 53

POINTS ARISING 58

ADVERTISERS' INDEX 62

NEXT MONTH...

SAFETY POWER UNITS - MORE G.C.S.E. PROJECT IDEAS S SECURITY ALARM CONTROLLERS • MIDI EXPANDER S SEMICONDUCTOR TECHNOLOGY • LASERS AND OPTICAL FIBRES

• PROGRAMMABLE LOGIC DEVICES PARTTWO • DC MOTORS PART THREE • ROBOTICS AND EDUCATION. AND OF COURSE our top line regular features, exciting experimental ideas, and all the latest product information from our advertisers.

PE NOVEMBER 1987 ISSUE ON SALE FROM FRIDAYOCTOBER 2nd - DON'T MISS YOUR COPY PLACE A REGULAR ORDER IT'S STILL ONLY £1.25

November 1987 PE vol. 23 no. 11

CONSTRUCTIONAL PROJECTS

INTRUDER ALARM CONTROLLERS PART ONE by Bill Kent 12

Alarming procedures need taking to deter thieves and vandals. Bill Kent discusses some practicalities.

MIDI EXPANDER by Robert Penfold 24

Musical profusion through patched up tuning - or how to become a solo band without really trying.

TEACHER POWER by Tim Pike 35

Another feature for G.C.S.E. students in which power supplies are examined and a working example described.

COMPUTER D.C. MOTOR CONTROLLER by Mark Stuart 43

Programmed model mobilisation is readily achieved with this micro to motor interface.

SPECIAL FEATURES

SEMICONDUCTORS PART ONE by Andrew Armstrong 17

The first of a series of articles demystifying the business of choosing and using semiconductors.

OPTIC FIBRES, LASERS AND COMMUNICATIONS by Barry Fox 27

The digitised harnessing of light increases the speed and reliability of communications, despite an odd joker in the fibre pack.

PROGRAMMABLE LOGIC DEVICES PARTTWO by Chris Kelly 49

PLDs turn design dreams into speedy hardware reality, especially when PALs, FPGAs are programmed.

CLASSROOM ROBOTICS by Lawrence Hamburg 54

Practical control of robots teaches analysis techniques and instils an understanding of the disciplines neededfor the adult world.

REGULAR FEATURES

EDITORIAL-Security 9

LEADING EDGE by Barry Fox -The quality of Dallas 8

SPACEWATCH by Dr. Patrick Moore OBE -A true double quasar?. 46

INDUSTRY NOTEBOOK by Tom Ivall - Five billion customers 57

MARKETPLACE -what's new, where and when 4

PCB SERVICE - professional PCBs for PE Projects 60

TRACK CENTRE - the PCB track layout pages 32

CHIPCHOP-a technical logic research analyser 41

BAZAAR - Readers' FREE advertising service 56

ADVERTISERS' INDEX 62

NEXT MONTH...

RADIO RECEIVER - ANOTHER GCSE PROJECT IDEA • MULTIZONE BURGLAR ALARM • RS232C TO MIDI CONVERTER • SEMICONDUCTOR TECHNOLOGY • CODED LOCK TECHNIQUES . APPLIANCE TIMER • TELEPHONES ANCIENT AND MODERN S SOLAR CELLS. AND in addition to our top line regular features, exciting experimental ideas, plus all the latest product information from our advertisers.

THERE IS ALSO A HIGHLY INFORMATIVE, COLOURFUL DATA CARD

DON'T MISS YOUR COPY OF THE PE DECEMBER 1987 ISSUE

ON SALE FROM FRIDAY NOVEMBER 6TH

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