ELECTRONICS AUSTRALIA'S `CIRCUIT AND DESIGN IDEAS'
name + date
Pumping up the Powerup - hints for the August 2000 project Sep 00
Car lamp failure warning - brake lights Sep 00
Globes flasher for the festive season (240VAC) Sep 00
Professional finish for aluminium panels Aug 00
Soundcard input protector - clipping preamp + indicator Aug 00
Better smarter blown-fuse indicator - see May 2000 CDI Aug 00
7-segment AC/DC indicator Jul 00
Driver for digital countdown timer - switch clock/watch Jul 00
Dual mode battery charger - 12V, const current & trickle Jul 00
Simple Waa-waa circuit Jul 00
Overvoltage protector for 3-terminal regulators Jun 00
The Dip Led - a LED DIP meter Jun 00
Golf buggy speed control Jun 00
Clipping indicator for opamp stages Jun 00
Versatile latching touch switch May 00
Low-cost, high-current regulator May 00
Smarter blown-fuse indicator May 00
Cooling fan controller saves power May 00
Exclusive-OR (XOR) function from discrete components Apr 00
12V battery conditioner (discharge checker) Apr 00
Speed up relay closing time Apr 00
Soft audio limiter Mar 00
Linux/PERL sprinkler script for Serial I/O Interface (Jul 91) Mar 00
Funway doorbell modification - auto shutdown Mar 00
Simple ESR tester (meter) Mar 00
Simple, beefy dual power supply Feb 00
Variable stero field circuit Feb 00
DC to DC converter for small valve radios Feb 00
Multipoint digital temperature monitor (LCD readout) Jan 00
Brother Multifunction Centre (MFC) to PC interface Jan 00
Cheap and cheerful tensistor tester Jan 00
Fitting modular telephone plugs Dec 99
LAN cable tester Dec 99
Parallel port interface (with BASIC software) Dec 99
Measuring very high value capacitors Dec 99
Drilling template for PCBs Nov 99
Soldering iron controller Nov 99
Simple 240VAC power switching for (ATX) PCs Nov 99
Servo amplifier Nov 99
LED mains voltage monitor Oct 99
Phone recording device switch Oct 99
Illuminated button, turn-off delay for Designer Door Alert Oct 99
Remote alarm to central-locking interface for cars Oct 99
Let your PC talk to IIC (I squared C) devices Sep 99
Water tank level monitor Sep 99
Use salvaged VCR sensors Sep 99
Two ICs drive two stepper motors Aug 99
PC's CMOS battery replacement Aug 99
Single channel IR remote control Aug 99
Simple LED voltmeter using 741 opamps Jul 99
Screecher MkII car alarm modification Jul 99
Solid state ballast bypass for cars Jul 99
Logic analyser uses TI graphing calculator Jul 99
Downlight controller Jul 99
Water detector - simple & efficient Jun 99
Car detector for driveways - imbedded coil Jun 99
Soft start for car lights Jun 99
ESR & charge current tester for car batteries Jun 99
Auto arming EA's engine immobiliser May 99
Low dropout voltage regulator May 99
High efficiency LED flasher May 99
Automatic central locking while driving May 99
Simple DC supply needs no thermal mounting hardware Apr 99
Door watcher - multiple doors Apr 99
Brakelight monitor for cars and trailers Apr 99
High-power alarm/siren driver (12V) Apr 99
'Pulser' for car electric fuel pumps Mar 99
Alarm status indicator - for home and car alarms Mar 99
Electronic 'Stomp Box' Mar 99
Mains usage monitor Mar 99
Two line, 10-channel control Feb 99
Clap-operated on/off switch Feb 99
Ring cadence simulator Feb 99
Current control for stepper motors Feb 99
Sound operated relay Jan 99
Flashing third brake light for cars Jan 99
Phase Bridge gives a free third audio channel Jan 99
Simple surround sound system - passive Dec 98
Bore pump timer Dec 98
Trailer light supply for European cars Dec 98
VHF preamplifier Dec 98
Wireless TV pattern generator - simple Nov 98
Loss of mains power indicator Nov 98
Curve tracer adaptor for DSOA Nov 98
Themocouple thermostat - mains swicthing Nov 98
Solar regulator (Nov/Dec 1994) modification Oct 98
Voltage controlled rotating LED display Oct 98
Whistler receiver for Earth's natural radio Oct 98
Uninterruptible Power Supply (UPS) for cordless phones Oct 98
Low current bargraph display Sep 98
Univeral IR controller for a PC - Infrared record/playback Sep 98
Novel running light display (chaser) Sep 98
Simple mod to improve Cable Break Finder (Feb 98) Sep 98
Linking up smoke alarms Aug 98
Simple inductance measurement using a CRO Aug 98
Photographic timer Aug 98
Longer battery life for the ESR meter Aug 98
AM radio re-transmitter Jul 98
Plant moisture monitor Jul 98
Infrared (IR) intruder alarm Jul 98
Automotive timing light - simple Jul 98
DIY keypad for microprocessors Jun 98
3V xenon strobe Jun 98
Driveway detector using pneumatics (garden hose) Jun 98
LCD digital panel meter input isolation circuit Jun 98
ESR meter measures batteries, too May 98
Low power bargraph voltmeter for cars May 98
40109 based Schmitt trigger - variable threshold May 98
Simple voltage reference for Pocket Sampler May 98
Hardware screen saver (PIR sensor) Apr 98
Fuel pump safety cutout for cars Apr 98
Mercury tilt switch alarm - (portable) Apr 98
Micropower single gate LED flasher Apr 98
Four by four-second voise recorder (ISD1416 chip) Mar 98
Car engine immobiliser with alarm Mar 98
Simple counting metronome with accented beat Mar 98
Add-on for Frequency Shifter project (gain/level management) Feb 98
Simple electronic key with time delay (12V) Feb 98
Radio control fail-safe with voltage guard Feb 98
Aid for soldering SMD components Jan 98
PC control for stepper motors Jan 98
Resonance meter and capacitor tester Jan 98
Electric fence tester Jan 98
Frequency divider gives 1:1 mark/space ratio output Dec 97
LED light supports wide supply range Dec 97
Pump controller for solar water heater Dec 97
Voltage reference modification for Pocket Sampler Dec 97
Electronic wind vane Nov 97
Finding breaks in shielded cables Nov 97
Turbo timer for diesel engines Nov 97
Zero blanking for 3.5 digit display (74C926) Nov 97
Telephone intercom Oct 97
Long duration one-shot Oct 97
Low dropout 5V regulator Oct 97
Simple sampler - uses PC parallel port Sep 97
Inexpensive power converter: 12VDC to 240VAC Sep 97
Headlights off indicator for cars Sep 97
JFET test adaptor for DMMs Sep 97
FM transmitter uses varicap tuning Aug 97
Booster for 12V motors Aug 97
Eye level car brake light flasher Aug 97
Unipolar stepper motor driver Aug 97
Automatic PIR doorbell Jul 97
Video test generator Jul 97
Front panels made easy Jul 97
Simple voltage regulator Jul 97
Supply makes LCD meter self-powered - 10V switching supply Jun 97
Micro-powered sound switch - uses latching relay Jun 97
Rugged 'knock' sensor Jun 97
Bit pattern detector aids micro development Jun 97
PC parallel port servo controller May 97
Light activated switch for battery powered circuits May 97
Simple temperature sensor gives linear output May 97
Language switch for Video CD players May 97
Chart for calculating file download times Apr 97
Suppy switching provides under-voltage lockout Apr 97
Delayed turn-off for car power windows Apr 97
Solid state switch for temperature controller - ref Aug 94 Apr 97
Heater switching system gives 3dB steps Mar 97
Turn indicator/blinker for cars Mar 97
Low voltage alarm for R/C receiver batteries Mar 97
Electro-mechanical battery charger Mar 97
Water level sensor Feb 97
Simple sleep timer for battery powered radio Feb 97
Remove components from PCBs with common heatgun Feb 97
UHF TV antenna Feb 97
Network cable tester Feb 97
Easy remote control tester Jan 97
Capacitance adaptor for analogue meters Jan 97
Car brake pedal alarm Jan 97
12V supply for compact fluorescent lamps Jan 97
Automatic video switching circuit Jan 97
Simple audible crystal checker Dec 96
Go/no-go tester for car ignition modules Dec 96
Brewer's temperature controller Dec 96
Frequency counter calibrator uses TV Dec 96
ADC supports up to 256 inputs Nov 96
Quiet line/buzzer alert for coms handset Nov 96
Battery charger auto cutout Nov 96
Crystal filter with variable selectivity Nov 96
Polarity probe - for cars Oct 96
Auxiliary telephone ringer Oct 96
Meter overload protector Oct 96
Clock alarm driven remote switch Oct 96
Port-powered MIDI interface fro the Mac Sep 96
CTCSS signal switching system Sep 96
Twin joystick adaptor for PC sound cards Sep 96
Overrange indicator for 1MHz pulse generator (June 92) Sep 96
One LED indicator for two computer hard drives Aug 96
Turn indicator warning device for cars Aug 96
Auto arming ignition killer for cars Aug 96
Clipping indicator for hifi amplifiers Aug 96
Simple temperature switch - germanium diode sensor Jul 96
1-bit fast ADC - stackable Jul 96
Off-air alarm for for radio studio Jul 96
One dollar watchdog timer for '8051 micros Jul 96
Rotary pot to 4-bit BCD converter Jun 96
Low cost emergency light system Jun 96
Simple timer for battery chargers Jun 96
Frequency meter for 'Vernus' audio sweeper (see Aug-Sept 92) Jun 96
Campervan fridge battery cutout - with warning beeper May 96
Computer network cable tester May 96
555 based waveform generator - square, triangle, sine May 96
Fax/modem computer auto power on May 96
Very low current LED flasher Apr 96
Sound intensity (level) meter Apr 96
Earth loop eliminator Apr 96
Sound triggered alarm Apr 96
Three-line intercom Mar 96
Simple battery charger - for NiCads, with 12 hr timer Mar 96
Handheld audio signal generator Mar 96
Low voltage monitor/indicator Feb 96
NiCad battery pack auto cut-off Feb 96
Clock auto dimmer - dims LEDs at night Feb 96
Plant moisture monitor Feb 96
Digital code lock - 4-bit Feb 96
12V battery charger - lead-acid, gates, etc Jan 96
Dual train controller - two trains on one track Jan 96
Simple logic probe Jan 96
Protected 50 ohm, 50dB pad (for comms) Jan 96
Reaction timer Dec 95
Microwave high-voltage diode tester Dec 95
Charging 12V NiCads from a 12V battery Dec 95
Personal emergency alarm (UHF link) Dec 95
24V to 12V DC converter for trailer lamps Nov 95
Multi-flash adaptor for cameras Nov 95
Phase controller for inductine loads - 240VAC Nov 95
Simple computer interface (+ BBS software) Nov 95
Simple inductance meter Oct 95
Simple capacitance meter Oct 95
Engraving pen Oct 95
Tap-on connections (attaching wires to car looms) Oct 95
Phone ring indicator (lamp) Sep 95
Solar panel booster - 3V to 9V Sep 95
Fan speed controller - 12V Sep 95
Variable timer Sep 95
Expanded scale voltage meter Sep 95
Micropower LED flasher Aug 95
NiCad battery charger - AC type Aug 95
Brake fluid level alarm Aug 95
Energy saver for computers Aug 95
Falling bomb simulator Jul 95
Water purity tester Jul 95
Silent telephone bell (lamp, via SS relay) Jul 95
Wideband current feedback amplifier Jul 95
Simple energy monitor (for mains power) Jun 95
Flashing beacon (programmable) Jun 95
Stable 100kHz source Jun 95
Oil temperature indicator for engines Jun 95
Etching PCBs (fast, no ferric chloride) May 95
First-event indicator (first of 16) May 95
Solar night light May 95
Switch-mode battery charger (lead-acid, gel) May 95
EA Light and Sound Trigger modification Apr 95
In-circuit transistor tester Apr 95
Fridge cooler (fan controller) Apr 95
Karaoke converter Apr 95
Current limiting switch (overload protection) Mar 95
Voltage and continuity tester for cars Mar 95
Cable tester (simple) Mar 95
NiCad cell tester Mar 95
Simple TRF radio Feb 95
Piezo screamer Feb 95
DTMF decoder Feb 95
LED display driver Feb 95
Dual polarity power supply Feb 95
Efficient linear power supply (1.25V - 30V @ 3A) Jan 95
Energy auditor (record appliance on-time) Jan 95
DVM milliohm adaptor Jan 95
Simple shed door alarm Jan 95
Temperature controller Dec 94
Transformer protector Dec 94
Speed controller for DC motors Dec 94
CDI for an outboard motor Dec 94
Telephone ring simulator Dec 94
DC voltage status indicator Nov 94
Crystal controlled timer Nov 94
Simple variable-temperature soldering iron Nov 94
Signal injector/tracer Nov 94
High voltage generator Nov 94
Simple solar powered light (charges NiCads) Oct 94
Computer controller for DC motors Oct 94
Simple two-tone doorbell Oct 94
Bicycle tail light Oct 94
Trailer reversing light Oct 94
Sound indicator for the sight-impaired Sep 94
Electronic fuse Sep 94
DTMF keypad interface Sep 94
Binary clock Sep 94
AC (mains) voltage finder Aug 94
Gel cell battery charger Aug 94
Guitar tuner Aug 94
Sensor-light operated door bell Jul 94
Closed loop alarm Jul 94
Keyless lock Jul 94
RPM (rev) meter Jul 94
Simple solar cell voltage regulator Jun 94
NiCad charger with peak voltage detection Jun 94
Simple capacitance meter Jun 94
Disk drive stepper motor driver Jun 94
Active guitar electronics (preamp) May 94
Compact logic probe (simple) May 94
Touch switch for dirty fingers May 94
Garage door circuit (simple) May 94
Sound interface for PCs Apr 94
Tri-mode LED light chaser Apr 94
Simple `twin tone' doorbell Apr 94
Amiga conversion for EPROM programmer Apr 94
Large capacitor tester Mar 94
80m shielded loop Mar 94
Intelligent battery charger (NiCad, delta peak det.) Mar 94
Model traffic lights Feb 94
Audio attenuator design Feb 94
Flashing lamp driver Feb 94
Mower battery voltage control Jan 94
Keyhole light Jan 94
Electrically-operated garage door Jan 94
Op-amp toggle Dec 93
Efficient +5V regulator Dec 93
Temperature compensated charger - SLA batts. Dec 93
Switching 240V relays Dec 93
Bi-directional PC port Nov 93
IR proximity detector Nov 93
Telephone STD bar Oct 93
Guitar distortion Oct 93
Add-on vibrato for toy organ Oct 93
Variable supply for masthead amp Sep 93
Lights after dark Sep 93
`Over-drive' circuit Sep 93
Electric fence tester Sep 93
Seven day indicator Aug 93
Shorted turns tester Aug 93
Circuit resistor substitute Aug 93
NiCad discharger Aug 93
Eight bit PWM Jul 93
DWM battery saver Jul 93
Transmission indicator Jul 93
Blinker reminder Jul 93
Logic gate identifier Jun 93
Cat detractor Jun 93
Courtesy light delay Jun 93
Pulser probe Jun 93
Old VCR remote controls May 93
Fuzz and wah-wah pedal May 93
Remote control tester May 93
Direct conversion receiver May 93
Audible logic probe Apr 93
Short/open detector Apr 93
Joystick fire button Apr 93
Battery checker Mar 93
Level indicator Mar 93
IR remote control Mar 93
Car light extender and headlight reminder Mar 93
Metronome with emphasised beat Feb 93
Audio test oscillator Feb 93
Transistor leads finder Feb 93
I/O for the Amiga Feb 93
Receiver modules Jan 93
Automatic turn off switch Jan 93
High current pulses Jan 93
Current-limited 120V regulator Dec 92
Twinkling star Dec 92
Fluorescent lamp driver Dec 92
Headlight warning Dec 92
Apple II robot controller Nov 92
Computer controlled power supply Nov 92
Improved adjustable three pin regulator Oct 92
Heightened stereo effect Oct 92
Telemetry converter Oct 92
TV headphones amp Oct 92
Foolproof battery charger (12V/20A) Sep 92
Electronic lock Sep 92
Multi-flash unit Sep 92
Master/slave power switch Aug 92
Fluorescent lamp driver Aug 92
Tastic timer Aug 92
Automatic scanning for CBs Jul 92
Car voltage monitor Jul 92
Acupuncture point finder Jul 92
On/off lighting switcher Jun 92
Modified Funway doorbell Jun 92
Audible temperature and oil alarm Jun 92
Constant-current transistor tester May 92
DC motor speed controller May 92
Mains-powered light delay May 92
Joystick fire button Apr 92
Short/open detector Apr 92
Remote control extender Apr 92
Audible logic probe Apr 92
Transistor leads identifier Mar 92
Capacitor leakage tester Mar 92
Sprinkler timer Mar 92
LED display board Feb 92
10 channel RS-232 device selector Feb 92
Automatic watering system Jan 92
Tristate buffer or OR gate Jan 92
1-99V DVM Jan 92
Car vandalism detector Dec 91
Temperature controller Dec 91
Turbo timer Dec 91
Sweep oscillator Dec 91
Poor man's logic probe Nov 91
Quiz game Nov 91
Computer interface Nov 91
Sound effects generator Oct 91
Low dropout voltage regulator Oct 91
Constant current charger Oct 91
Lightning meter for SWLs Oct 91
Automatic light switching Oct 91
12V battery regulator Sep 91
Crystal oven Sep 91
High-res LF adaptor for counter Sep 91
AM/FM car radio antenna Sep 91
RS-232 parallel converter Aug 91
Transistor pierce oscillator Aug 91
30V, 3A power supply Aug 91
Binary/gray/binary converter Jul 91
`No battery' alternator start-up Jul 91
Switching lamp dimmer Jul 91
40V inverter/doubler Jul 91
Remote IR tester Jul 91
LED torch Jun 91
Headphone amplifier Jun 91
Inbuilt VCR alarm Jun 91
Darkroom exposure meter Jun 91
Timer with memory May 91
Optical shaft encoder May 91
Water reticulation control box May 91
`Turbo' board for Tandy 1000 Apr 91
TV-locked frequency calibrator Apr 91
Mods to Aug 1990 logic probe Mar 91
LED signal indicator Mar 91
Online flasher Mar 91
Mains' frequency indicator Feb 91
Active antenna balun/preamp Feb 91
Windscreen washer tank monitor Feb 90
NiCad battery protector Jan 91
Courtesy light fader Jan 91
Crystal set AM tuner Jan 81
IR proximity detector Jan 91
Valve TV transformer provides isolation Dec 90
Xenon timing light Dec 90
Microwatt LED flasher Dec 90
Simple RF preamp Dec 90
`Easy fit' wiper delay Nov 90
Scrabble timer Nov 90
Improved ignition killer Nov 90
Audio reminder for bike blinkers Nov 90
Two-tone oscillator for SSB testing Nov 90
Logic probe Oct 90
Resettable games timer Oct 90
Battery operated strobe `beacon' Oct 90
Servo system for robotics Oct 90
Poor man's variac Sep 90
`Mosmarx' voltage multiplier Sep 90
Four component window detector Sep 90
Photographic slave flash Sep 90
Serial keypad encoder Aug 90
Tuned mains filter Aug 90
Seedling heater thermostat Aug 90
Novel `decision maker' Aug 90
Water level alarm Aug 90
Car alarm protector Aug 90
LED `scanner' VU display Jul 90
24 channels for ICOM 22S Jul 90
Quiz game circuit Jul 90
Improving a low cost phone Jul 90
Linear UJT sawtooth oscillator Jun 90
Checkerboard pattern generator for ATV Jun 90
QRP transmitter for 6m Jun 90
Op-amp `flipflop' Jun 90
Low battery voltage alarm May 90
Video dubbing sound editor May 90
Flexible variable supply May 90
Eight bit decode display driver Apr 90
Auto polarity selector Apr 90
`Auto' volume control Apr 90
Hi-efficiency 1.5V LED flasher Apr 90
Seed bed mist timer Mar 90
High current switchmode PSU Mar 90
High power dummy load Mar 90
Level control for well water Mar 90
IR proximity detector Feb 90
Automatic switch for Centronics printers Feb 90
Current sensing pilot lamp Feb 90
Milliohm DMM adaptor Jan 90
12V/240V inverter for 80W fluoro lamp Jan 90
TTL logic probe Jan 90
RS-232 data monitor Jan 90
Mains controller for Commodore 64 Dec 89
Bi-directional motor controller Dec 89
Low power inverter Dec 89
Stereo dynamic expander Dec 89
Reading remote keypads in hostile environment Nov 89
Audio digitiser for Amiga Nov 89
Alarm for deaf people Nov 89
Doorbell pushbutton turns on porch light Nov 89
12-bit A to D converter Oct 89
Manual control for automatic car antenna Oct 89
Remotely adjustable aerial attenuator Oct 89
Neater wire joints Sep 89
Joystick for IBM compatibles Sep 89
Test message generator Sep 89
Midi tester, opto replacement Aug 89
Synthetic dual matched pot Aug 89
Powering solid state gear from valve equipment Aug 89
Mains failure alarm Aug 89
Oscilloscope aid for microprocessors Aug 89
High-Z voltmeter Jul 89
`Lights on' alarm Jul 89
Digital dice Jul 89
Joystick `Y' adaptor Jul 89
Telephone ring/busy dialtone detector Jul 89
Keyboard sound improver Jun 89
Substitute for multi-turn pot Jun 89
Self-arming ignition killer Jun 89
Parts counter Jun 89
Claytons car alarm May 89
Decimal display of binary numbers May 89
Slave flash unit May 89
Combination lock May 89
Joystick auto fire Apr 89
Guitar tuner Apr 89
Tape fader Apr 89
High impedance amplifier Apr 89
$20 plasma display Mar 89
One chip audio mixer Mar 89
Transformer tips Mar 89
Switch interlock Mar 89
Propeller tacho Feb 89
Recharger for single dry cells Feb 89
Multiple dry cell recharger Feb 89
Fan controller Feb 89
Electrolytic capacitor tester Jan 89
Logic testers Jan 89
Serial to parallel interface Jan 89
TV antenna switching Dec 88
Cascading regulators Dec 88
RS232 wiring tester Dec 88
One button on-off Dec 88
Leading zero blanking Dec 88
Beat trigger strobe light Nov 88
Logic level change detector Nov 88
Cascading 4017 counters Nov 88
Capacitance meter Nov 88
Operating a relay at reduced voltage Oct 88
250VA inverter Oct 88
Solid state `soft start' relay Oct 88
Suppressed zero voltmeter Sep 88
Three transistor amplifier Sep 88
Backup alarm control Sep 88
High pass filter for TV Aug 88
Sump/bilge pump controller Aug 88
Dimmer for torches Aug 88
TTL-RGB to composite video converter Aug 88
Standby power supply monitor Jul 88
14H battery charging timer Jul 88
Logic pulser Jul 88
Electronic BCD switch Jun 88
Four digit combination lock Jun 88
Car battery discharge indicator Jun 88
`Keep awake' for Concertmate 500 May 88
Linear scale on/off timer May 88
Soldering iron timer with `time up' beeper Apr 88
Electronic `flasher' novelty Apr 88
12V stroboscope for portable use Apr 88
Geiger counter Mar 88
Darlington assisted switch Mar 88
Auto-run circuit for fridges Mar 88
Cutting holes in Scotchcal Dynamark labels Mar 88
D/A and A/D for Apple II Feb 88
Light chaser/controller Feb 88
Automatic switching for UHF converter Jan 88
Expanding range of capacitance meter Jan 88
Improved glow plug regulator Jan 88
Multi-channel display Dec 87
Electronic die for games Dec 87
Soldering iron timer Dec 87
Fast peak limiter Dec 87
I/O expansion for Apple II+ Nov 87
Deep-cycle NiCad charger Nov 87
Refrigerator auto-run unit Nov 87
Improved battery charger controller Oct 87
Car accessories timer Oct 87
Cable tester Oct 87
Turn indicator flasher Sep 87
Centronics interface for Apple II Sep 87
Wipe effects for the video fader Sep 87
24V/12V regulator Aug 87
Simple doorbell Aug 87
El cheapo frequency reference Aug 87
Low battery indicator Aug 87
Complex impedance meter Aug 87
Low current circuit breaker Jul 87
General purpose counter Jul 87
Benchtop DC ammeter Jul 87
Memory expansion for the VIC-20 Jul 87
Dual rails from a single battery Jun 87
Transistor tester add-on for multimeter Jun 87
Magnetic pickup for digital speedometer Jun 87
Screecher protection for bonnet and boot Jun 87
Quiz game adjudicator Jun 87
16K memory for VZ-300 computer May 87
Tone decoder for CBers & amateurs May 87
TV hearing aid May 87
Crude but simple voltage reducer May 87
Battery backup for bicycles Apr 87
Brightness control for torches Apr 87
NiCad charger with auto float charge Apr 87
Precision V/F converter Apr 87
IC preamplifier Mar 87
Low current power amplifier Mar 87
Temperature comparator Mar 87
Great circle calculator for the Amstrad 6128 Mar 87
Sensitive trigger for slave flash guns Feb 87
Four utility circuits using a hex Schmitt trigger Feb 87
ECG waveform display on Apple II computer Jan 87
Digital speedometer for cars Jan 87
Computer drive for EA EPROM programmer Jan 87
Loudspeaker switching circuit for car/radio/cassette Dec 86
Rechargeable 12V torch Dec 86
Brake lamp flasher modification Dec 86
Radio remote control Dec 86
Decimal points for EA 500MHz DFM Dec 86
Basic program for vented box enclosures Nov 86
Modified audio generator Nov 86
Extra decimal points for EA DFM Nov 86
TV based frequency standard Nov 86
Addenda for 1.5V photoflash inverter Oct 86
Ignition switch cutout for car alarms Oct 86
Low pass filter and surge suppressor Oct 86
How to cascade 4017 counters Oct 86
Improved model railway lighting Oct 86
How to gang single potentiometers Sep 86
Battery charger controller Sep 86
Amplitude modulation for function generator Sep 86
Whistle stopper for PC birdies Sep 86
Electronic sprinkler timer Aug 86
Connecting VCR to two TV sets Aug 86
1.5V photoflash inverter Aug 86
Electronic vibrator for car radio Jul 86
Wien bridge sinewave oscillator Jul 86
Farm gate movement detector Jul 86
Strength meter for parties Jul 86
Negative rail from bridge power supplies Jun 86
Low cost technique for diagnostic training Jun 86
Setting the output of the 300W inverter Jun 86
A mouse for the cat Jun 86
Lights on reminder for cars Jun 86
Sound effects for toy guns Jun 86
Microprocessor memory expansion Jun 86
High performance audio generator May 86
FM and AM modulation for EA function generator May 86
Burglar alarm deterrent flasher May 86
Computer program aim beam antennas May 86
Microphone preamp and peak level indicator Apr 86
Cure for doorbell pests Apr 86
Automatic shut-off for soldering irons Apr 86
LED tuning indicator for AM stereo decoder Apr 86
Novel lamp flasher uses no capacitor Mar 86
Code switch Mar 86
LED flasher for torches Mar 86
Desoldering tools for ICs Feb 86
Three way combination lock Feb 86
Modified soft pedal for Lyrebird piano Feb 86
People monitor and light switch Jan 86
Ignition advance for alternative fuels Jan 86
A clutch of charge pumps Dec 85
Knight Rider scanner light Dec 85
Solid state bicycle tail light Dec 85
Speed control monitors Dec 85
16 channel data samples for Microbee Nov 85
Infrared door minder Nov 85
Camera timer Nov 85
Digital logic tester Nov 85
Audible engine temperature alarm Nov 85
Video controlled power switch for TV Nov 85
Balanced microphone input stage Oct 85
Modification to Pools/Lotto selector Oct 85
Projection lamp warm up unit Oct 85
Night time lamp flasher Oct 85
Solar panel regulator Oct 85
Headlight reminder and burglar deterrent Sep 85
Auto dialling/auto answer attachment for modems Sep 85
3-1/2 digit display controller Aug 85
Operating relays from low voltage supply Aug 85
Adjustable supply to +/-100V at 0.25A Aug 85
Latched indicators for multi-sector alarm Jul 85
Combination switch/lock Jul 85
Radio/cassette addition to motorcycle intercom Jul 85
4000 series CMOS gate tester Jul 85
CRO adaptor for RMS measurements Jun 85
Infrared diode amplifier Jun 85
Hee haw siren using piezo buzzer Jun 85
88kHz notch filter for CD players Jun 85
Infrared remote keyboard Jun 85
Low cost transistor tester May 85
Calibrating meter shunts May 85
Inverter modification May 85
Ding dong doorbell May 85
Cistern pump timer Apr 85
Program for RS232 printer interface Apr 85
Headlight control circuit Apr 85
Sequential controller for tape recorders Apr 85
Knight Rider scanner light Mar 85
300 baud infrared data link Mar 85
Low power relay energisation Mar 85
Inverse RIAA attenuator Feb 85
Guitar tuner Feb 85
Breakdown voltage test jig Feb 85
Ultrasonic alarm Feb 85
Modification to Railmaster train controller Jan 85
Beeper for vehicle flasher Jan 85
Checking transistors with a multimeter Jan 85
Capacitance meter Jan 85
Pulse generator Jan 85
Low noise mic pre-amp Dec 84
Modifying the EA car alarm Dec 84
Automatic turn-off switch Dec 84
Impulse tacho for TAI Dec 84
Monophonic organ Dec 84
24V to 12V converter Dec 84
Multi-channel CRO adaptor Nov 84
RS232C serial A-D converter Nov 84
Metronome with accented beat Nov 84
13.8 power supply Oct 84
Quiz game adjudicator with digital scoring Oct 84
50Hz frequency indicator Oct 84
Baud rate generator Oct 84
Childproofing battery operated doorbells Oct 84
Video switch for Apple computers Oct 84
Light sensitive switch Oct 84
IF/audio circuit for VHF receiver Oct 84
Auto-chime modifications Sep 84
Adjustable peak limiter Sep 84
CMOS touch switch for infrared TV sound control Sep 84
Thermal balance switch Sep 84
Glitch catcher and line filter Sep 84
Car alarm Sep 84
Automatic antenna retraction Sep 84
Two way radio alarm tone generator Aug 84
Improved graphics for VZ200 computer Aug 84
Logic pulser probe Aug 84
Dual counter trip meter Aug 84
6V car adaptor Jul 84
Fuse-failure indicator Jul 84
Wireless link for musical keyboard Jul 84
Bi-colour LED gives varying hue Jul 84
Burglar alarm reminder Jul 84
Crowbar protection for 13.8V supplies Jun 84
Automatic volume control Jun 84
Modified supply for storage CRO adaptor Jun 84
Single pushbutton long period timer Jun 84
Extended response sound switch Jun 84
Audible indicators for panel lamps Jun 84
Car navigation aid May 84
Fluid level detector May 84
Tone generator for Super-80 computer May 84
Digital sweep/market generator Apr 84
Modifying the EA EPROM programmer Apr 84
High power dummy loads Apr 84
Variable frequency oscillator Mar 84
Throbotron light show Mar 84
EPROM programmer beeper Mar 84
Burglar alarm Mar 84
10A regulated photo enlarger supply Mar 84
VIC-20 video terminal Feb 84
NiCad charger with automatic shutoff Feb 84
SWR meter Feb 84
Linear frequency control for the 555 timer Feb 84
Extra RAM for the VIC-20 Jan 84
Multiple flash trigger for camera flash guns Jan 84
Hex display for EPROM programmer Jan 84
Stereo sound for TV Dec 83
NiCad charger Dec 83
Improving the solenoid Nov 83
Effective joystick Nov 83
Dual trace CRO adaptors Nov 83
Flame detector circuit controls booster fans Oct 83
Wide range capacitance meter Oct 83
IC sockets and double sided boards Oct 83
Glow plug driver for model planes Oct 83
Frequency doubler uses one comparator Oct 83
Mains derived TTL clock Sep 83
Beeper for the Super-80 Sep 83
Regulated enlarger power supply Sep 83
Transient muting for preamplifier Sep 83
Battery indicator for small boats Sep 83
Mounting small speakers Sep 83
Electronic detent circuit Sep 83
Tachometers and CD ignition systems Aug 83
EPROM adaptor for EA programmer Aug 83
Modified light chaser gives cylon eye display Aug 83
PCB pattern suggestion Aug 83
Wide range low distortion sweep oscillator Aug 83
Reverse polarity protection circuit Jul 83
Heavy duty joystick for VIC-290 Jul 83
Composite video signal generator using NOR gates Jul 83
Digital clock monitor with audible output Jul 83
Extra RAM for the DREAM 6802 microcomputer Jul 83
Leading zero blanking for Playmaster AM Jun 83
Quiz game adjudicator Jun 83
Updating the pools/lotto selector Jun 83
Audio indicator for the heart rate monitor Jun 83
Economy meter with km/l readout May 83
Hold function for digital frequency meter May 83
Pushbutton sequential switch May 83
Cassette interface for the VIC-20 PC May 83
Power failure indicator Apr 83
Model railway signal override system Apr 83
Analog multiplexer and op-amp D/A converter Mar 83
Current limiting for the VK Powermate Mar 83
Loudspeaker protection for high power amps Mar 83
Burnout protector for ohmmeter ranges Mar 83
500MHz prescaler for digital frequency meters Mar 83
Stripper modification for wire wrapping Feb 83
Suppressed zero car voltmeter Feb 83
Hex display for EPROM programmer Jan 83
Pre-regulator for EA power supply Jan 83
Improved triangle-to-sine wave converter Jan 83
Headlight reminder Dec 82
Expanded scale voltmeter Dec 82
Darkroom timer has audible output Dec 82
Personal portable modification Dec 82
Four tone sound for the Super-80 Dec 82
Digital chess clock with time out alarm Dec 82
Cudlipp's sister a ladybug Nov 82
Signal controller for model trains Nov 82
Relay power saver Sep 82
CRO trigger for EA TV pattern generator Sep 82
Remember the lights! Sep 82
Fractional frequency multiplier Sep 82
Bugging a lizard on the FM broadcast band Sep 82
Use your DVM as a capacitance meter Aug 82
Four hour photographic timer Aug 82
Computer as pattern generator Aug 82
Playmaster tone control bypass Aug 82
Regulated supply for flash meter Aug 82
Customised keytops Jul 82
TRS-80 cassette control Jul 82
Recycling etchant solution Jul 82
Fast switching solid state relay Jul 82
Resuscitation training aid Jul 82
Measuring top speed Jul 82
Transistor checker Jul 82
Programmed switch-on for IR remote control Jul 82
Lights for model railways Jun 82
Pseudo PC board Jun 82
Cudlipp's brother Jun 82
Audible logic tester Jun 82
Electronic thermostat Jun 82
Power inverter for motor driven antenna May 82
Alarm and fast shift for EA control timer May 82
Novel Wien bridge Apr 82
Auto repeat function for RCA VP 601 keyboard Apr 82
Mains auto transformer Apr 82
Register display routine for the `Sorcerer' Apr 82
Up/down pushbutton-controlled power supply Apr 82
Relay latching circuit Mar 82
Battery tester for the visually impaired Mar 82
Switch-mode control of low voltage DC motors Mar 82
Cure fluctuating dwell and tacho readings Mar 82
Suppressing audio switching transients Mar 82
Noise gate Feb 82
Low power probe Feb 82
Automatic reversing lamps Feb 82
Crowbar protector Feb 82
Use infrared relay as door minder Feb 82
Hum measurements Jan 82
LED indicator for remote AC loads Jan 82
Modifications to the utility timer Jan 82
`Patch' for Dream 6800 kaleidoscope program Jan 82
Audio flasher Jan 82
Musical tone generator peripheral Jan 82
Voltage to frequency converter Dec 81
Use your empty desoldering wick spool Dec 81
Balanced isolation amplifier Dec 81
Increased sensitivity for infrared relay Dec 81
Dynamic noise reducer for audio systems Dec 81
Random pulse width generator uses two ICs Dec 81
True peak-reading DC voltmeter Nov 81
Single button sequential switcher Nov 81
Calibrator for DC meters Nov 81
Video summing amplifier Nov 81
Single IC logic tester Nov 81
Variable-phase all-pass filter Oct 81
Pseudo random number generator Oct 81
Marine auto pilot for small boats Oct 81
Simulate a NiCad cell Sep 81
Regulator with low dropout voltage Sep 81
Headlight reminder alarm Sep 81
Touch Switch Sep 81
Active DC load Sep 81
NiCad battery charger Sep 81
Lifetime lettering Aug 81
Linear LED control Aug 81
Model train points changer Aug 81
IC testing board Jul 81
One transformer, two secondaries, three supply rails Jul 81
Random number generator with 3 ICs Jul 81
Bi-colour LEDs indicate switch position Jun 81
Decimal points for the 200MHz frequency counter Jun 81
Modified `Prospector' metal locator Jun 81
Tunnel diode wobbulator Jun 81
Intermediate intervals for utility timer Jun 81
More power from dual or quad op-amps May 81
Head/parking light reminder alarm May 81
Converting electronic music box to pushbutton operation May 81
Analog memory May 81
Electronic thermometer with digital display May 81
Simulation of ignition primary circuit pulses Apr 81
Up/down glide tone generator Apr 81
5V logic tester with audio buzzer Mar 81
Fuse failure indicator Mar 81
TTL over-voltage protection Mar 81
Add milliohms measurement to your digital multimeter Feb 81
Auto-start for 12-230V AC inverter Feb 81
Modification adds versatility to electronic keyer Jan 81
Lightning protection for high pass filter Jan 81
Voltage controlled amplifier Jan 81
Phase meter for audio frequencies Jan 81
Novel application for Mini Scamp Jan 81
VDU mod gives 64 characters per line Dec 80
High frequency doubling with CMOS Dec 80
Modification gives pulsed output for Utility Timer Dec 80
PLL lock indicator detects latching simply Nov 80
Wave shaper uses one 4017 IC Nov 80
15V/0.5A power supply with good regulation and temp stability Nov 80
Low voltage light chaser provides four separate outputs Nov 80
Economical white noise source Oct 80
LC network adapts PLL for crystal-overtone operation Oct 80
Symmetrical power supply Oct 80
Audio-visual continuity tester Oct 80
Timer takes very low current Oct 80
Automatic switch-off circuit saves batteries Sep 80
Bi-directional LED chaser Sep 80
Single switch doubles bridge voltage Aug 80
Digital readout for HF receiver using standard counter Aug 80
Unity gain buffer with wide frequency range Aug 80
Automatic multiple flash unit for photographers Aug 80
LED flasher Jul 80
Modification to wiper delay unit Jul 80
Improved resistance-capacitance oscillator Jun 80
Bridge measures unknown resistance and capacitance Jun 80
Headlight minder saves battery discharge May 80
555 timer triggered by positive pulses May 80
High pass filter for masthead amplifier May 80
Electronic security lock has non-volatile latch memory May 80
Mosto calculators for incremental counting Apr 80
Fuzz for electric guitar Apr 80
Self resetting burglar alarm Apr 80
Readout dimmer for six digital crystal clock Apr 80
Joystick control Mar 80
Decimal and binary learning tool Mar 80
Modification to sound triggered photo flash Mar 80
Test reaction times on the 2650 Mar 80
Solid state scope uses LEDs Mar 80
High current regulated power supply Feb 80
Direct derivation of baud rate clock signals from a 4MHz clock Feb 80
Novel way to play your old 78s Feb 80
Auto-chime - which tune is next? Feb 80
Make before break meter switching Jan 80
Counter records number of camera shutter openings Jan 80
On screen clock with 2650 Jan 80
Alarm for digital clock uses two CMOS oscillators Jan 80
Flash strobe addition to sound triggered photo flash Jan 80
Novel vice to make Dec 79
Adjustment power supply up to +/-12V and 800mA Dec 79
Frequency doubler Dec 79
Accurate motor speed control Dec 79
Autodim for fluorescent clock displays Nov 79
Six digit facility for four digit clocks Nov 79
TTL compatible audio switch Oct 79
Audio/video monitor for EA terminal keyboard Oct 79
Note on opto-coupled magnet driver for teleprinters Oct 79
Tracking dual voltage regulator Oct 79
Lock switch for desk mains digital clock Sep 79
Music for your lawn! Sep 79
Novel method for desoldering IC devices Sep 79
Voltage reference uses op-amp Sep 79
JFET preamplifier for tired receivers Aug 79
W1JR HF broadband balun Aug 79
Recording DC power using a chart recorder Jun 79
Opto-coupled magnet driver for teleprinters Jun 79
General purpose fault finding probe Jun 79
Comprehensive cable tester Jun 79
Interesting two-wire intercom May 79
Bounce free switch May 79
Variable current limiter for power supplies May 79
Transistor lead identification May 79
Protection for DC coupled speakers May 79
Noise generator Apr 79
Hee haw siren for toys Apr 79
Auto repeat for keyboard Apr 79
Handy aid to fine soldering Apr 79
Caravan DC power - a better way Apr 79
Dual function neon indicator Mar 79
Cross coupled transistor rectifier bridge Mar 79
Preamplifier for microphones, mixers, etc Mar 79
Wien bridge and op-amp select filter's bandwidth Mar 79
Try this simple diode tester Feb 79
Non-destructive backspace, space and line feed for VDU Feb 79
Crystal oscillator suits 2650 minicomputer Feb 79
CW operation on 3.5MHz transverter Feb 79
Modification lets PIPBUG work at 300 baud Feb 79
FM square and triangular wave generator Jan 79
Handy patch panel in a box Jan 79
D flipflops sense locked state of PLL Jan 79
