Updated Pages



AM Transmitter Circuit 4-8-01
New Timing Circuit Section Added 4-8-01
555 Monostable 4-8-01
IR Extender Circuit Updated with IC pinout and new fault finding text.11-8-01
Buzzer Circuit by Tom 13-8-01
6 x 6 Loop Antenna A new 6 foot loop antenna by Graham Maynard
Radio Wave Alarm by Rev Thomas Scarborough 21-10-01
2 Transistor Transmitter from Rob van der Weijden 21-10-01
5 to 30 minute timer circuit 25-10-01
Simple UPS 27-10-01
Designing Unregulated Power Supplies (first article for a long time) 27-10-01
Dark Activated Switch Updated 1-11-01
Links page updated 3-12-01
Download page updated 3-12-01
Enhanced Alarm Keypad by Ron J 3-12-01
15 Watt amplifier circuit by Sergio Garcia 3-12-01
IC pinouts added to Practical section 5-12-01
IR Extender Circuit Mark II 5-12-01
4 Digit Keypad by Ron J 9-12-01
12V 30A PSU page updated 7-1-02
Milligauss Meter by Rev. Thomas Scarborough 8-1-02
Home Page updated (There is nothing wrong with your sound card the midi has been removed) 8-1-02
Over Voltage Protection Circuit for LM317 by Adam 8-1-02
FM Receiver Using MPF102 by Patrick Cambre 8-1-02
Alarm PSU by Ron J 8-1-02
Infra Red Swich 8-1-02
Links Updated 16-1-02
French Intro page kindly translated by Olivier Decelle 9-2-02
IR Extender MK1 updated . Special thanks to Domenico for drafting the PCB 9-2-02
Combinational Conjuring Trick by Rev Thomas Scarborough 11-2-02
Mk2 IR extender updated with a PCB kindly drafted by Domenico
Motorcycle Alarm from Ron J 11-2-02
Links Updated 11-2-02
Credit list updated 23-2-02
Switch and Relay Contact Designation added to Practical Section 23-2-02
DC Motor Reversing Circuit 25-2-02
Water Level Alarm 25-2-02
Audio VU Meter by Matthew Hewson 8-3-02
Sound Effects Generator 9-3-02
Cable Tester 12-3-02
Water Activated Relay by Marin Lukas 12-3-02
Soft Switching Amplifier with Tone Controls 18-3-02
Sound Effects Generator 2 18-3-02
Connection Tester 19-3-02
Metal Detector 19-3-02
Sine Wave Generator 20-3-02
SW RF amplifier 20-3-02
Electronic Siren 21-3-02
High Quality Intercom 21-3-02
Doorbell for the Deaf 22-3-02
Audio Level Meter 22-03-02
ZN414 / MK484 Receiver Page updated 25-2-02
Model Rocket Launch Controller 18-5-02
Band 2 VHF Amplifier 18-5-02
IR Link by Ron J 20-7-02
Bipolar Regenerative Receiver by Ramon vargas 3-10-02
Single Zone alarm by Ron J 3-10-02
Transformerless Power Supply Updated text by Ron J 3-10-02
IR extender Mark 2 circuit text updated 24-10-02
Help Page Updated 29-10-02
Dynamic Microphone Preamplifierr 29-10-02
Doorbell with Counter updated 31-10-02
Links page updated 31-10-02
Bipolar Regenerative Receiver by Ramon vargas update 16-12-02
Triac Light Controller by Matthew Hewson 4-1-03
Modulation Detector for IR Remote Controls 7-1-03
Drawing Veroboard Layouts by Ron J 10-1-03
A 13.8V 20A PSU by Bob from Croatia 14-1-03
Output Adjustable Flyback Converter by Simon Oh 14-1-03
Remote Control Extender Mk 3 by Daniel Pozzi 20-1-03
Remote Control Extender Mk 4 20-103
Which Remote Control Extender do I use ? 20-1-03
Laser Communication System by Marin Lukas 20-1-03
A 13.8V 20A PSU PCB added to Bob's Circuit in PDF format 7-2-03
Remote Control Extender Mk 4 compatible handset list updated 7-2-03
R5000 Receiver Interface 3-3-03
9 Volt 2 Amp PSU 4-3-03
IR Link by Milan Markovic 4-3-03
Periodic Timer 4-3-03
Help Page updated 24-5-03
CMOS Single Zone Alarm by Ron J 24-5-03
Decimal to BCD Convertor by Ron J 24-5-03
Current Limiting Power Supply by Ron J 5-8-03
Asymmetric Timer 5-8-03
Variable Power Supply Correction to Diagram Pins 2 and 5 reversed 5-8-03
Logic PSU with Over Voltage Protection Updated text and circuit 8-8-03
Audio Indicator 13-8-03
Headphone Amplifier 18-8-03
ECM amplifier Updated Schematic 18-3-03
Radar Detector External Link to Cyber Circuits
Help Page Updated 17-9-03
Crystal Controlled Oscillator by Ramon Vargas 18-9-09
24 Hour Timer by Ron J 18-9-03
Switch Debouncer Diagram corrected 20-9-03
Crystal Controlled Oscillator by Ramon Vargas Updated with Pics 18-10-09
Links Page Updated 11-11-03
Help Page Updated 21-11-03
Negative Voltage Load Switch by Nicholas Choong 22-11-03
Short Wave Regenerative Receiver by Ramon Vargas 22-11-03
A Collection of Mini-Alarms by Ron J 22-11-03
Warning: New IC's added to the Pinouts Page 1-12-03
Cable Tester Page update with IC Pinout 2-12-03
Using ECM Mic Inserts 3-12-03
Crystal Test Circuits 3-12-03
IR Extender Mk 4 More compatible handsets listed 5-12-03
DC Theory Updated 21-2-04
5 Zone Alarm Text Updated 27-2-04
Car Alarm and Immobilizer by Ron J 27-3-04
Updated disliamer 7-4-04
How to Create a Parts List (Practical Section)12-4-04
Updated help page 12-4-04
Dealing with Spam 12-4-04
Bench Amplifier 12-4-04
HiJack Alarm by Ron J 12-4-04
Hi Quality Intercom update with PCB by Corey Rametta 12-4-04
IR Extender Mk3 Update now includes PCB from Claudio Apicella 21-3-04
Credits page updated 21-3-04
Hot Water Indicator updated 22-4-04
IR switch Updated 22-4-04
Cold Switch Updated 24-4-04
Signal Injector and Tracer 5-5-04
Snore Alarm 5-5-04
From Schematic to Veroboard - How to build your design from the circuit. 5-5-04
Wien Bridge Oscillator (Design Section) by Ramon Vargas 20-8-04
Beat Balance Metal Detector by Rev. Thomas Scarborough 20-8-04
Coil Coupled Operation Metal Detector by Rev Thomas Scarborough 20-8-04
Help Page Updated 8-11-04
Analysis Page Given a New look 8-11-04
Q Multiplication in the Wien Bridge Oscillator by Ramon Vargas 8-11-04
Baxandall Tone Control Circuit by Ramon Vargas 8-11-04
Motorcycle Alarm 2 by Ron J 8-11-04
Motorcycle Alarm 3 by Ron J 8-11-04
Monitor Splitter by Miroslav Adzic 8-11-04
Supply Voltage Indicator by Miroslav Adzic 8-11-04
Infra Red Remote Extender Mark 5 8-11-04
Infra Red Remote Extender Mark 1 modified with Mk 1A version 8-11-04
Which Remote Control Extender ? Page Updated 8-11-04
LED Torch by Andre 8-11-04
LED Flasher by Andre 8-11-04
Radio Calculations by Harry Lythall external link added to theory secion 8-11-04
Op-Amp Tutorial by Tony Van Roon external link added to Design section 8-11-04
555 Timer Tutorial by Tony Van roon external link added to Design section 8-11-04
Heat Sinks for Transistors external link to Kelsey Park School added to Theory section 8-11-04
Circuit Index Updated 12-11-04
Help Page Updated 17-11-04
New Circuit Exchange Viewer Gallery 24-11-04
Pulse Generator by Miroslav Adzic 24-11-04
Small Variable power Supply by Miroslav Adzic 24-11-04
Voltage Controlled Switch by Miroslav Adzic 24-11-04
Telephone In-Use Indicator by Miroslav Adzic 24-11-04
Privacy Circuit by Miroslav Adzic 24-11-04
Soft Start Power Supply Circuits by Miroslav Adzic 24-11-04
Parts Storage & Label Template 24-11-04
FM Transmitter by David Celestin 23-12-04
IR Extender using PIC external link to Pete's World 10-2-05
Xenon Strobe External Link to Robert Dvoracek's Site 10-2-05
Universal Power Supply by Volker Jeschkeit 10-2-05
Interview with Rev. Thomas Scarborough (Media section) 10-2-05
Automatic Repeater by Miroslav Adzic 11-2-05
Diode Charge Pump AM-FM Demodulators by Ramon Vargas (Theory Section) 11-2-05
New! Article Index A-Z reference of all articles of all areas on this site 11-2-05
MK484 Complete Receiver by Chad Castagana 21-6-05
Add On Current Limiter by Ron J 22-6-05
24 Second Shot Clock by Milardo de Guzman 23-6-05
Camera Switcher by Milardo de Guzman 23-6-05
Motorcycle Alarm 4 by Ron J 23-6-05
Motorcycle Alarms 5 & 6 by Ron J 23-6-05
Transistor Configurations Updated 28-6-05
Negative Feedback in Amplifiers by Lazar Pancic Updated 28-6-05
New Home Page for DSL/ Broadband Connection 30-6-05
Transistor Configurations 2 21-7-05
Ignition Coil Driver by Robert Dvoracek 25-7-05 (External Link)
Electric Curtains 25-7-05
TV Transmitter by David Celestin 25-7-05
1.3V Power source 25-7-05
Mk5 IR Extender page updated with vero layout fault finding and veroboard layout. 12-8-05
Variable PSU by David Celestin 22-8-05
LED flasher by Evin Devore 23-8-05
Low Voltage Preamp 25-8-05
Fast Electronic Fuse by Miroslav Adzic 25-8-05
AM Modulator in the Spice Simulation Area 26-8-05
Class A//A-b Amplifier - a Class A/AB 100W by Graham Maynard 26-8-05
Remote Doorbell Switch page update 27-8-05
Passive Ethernet Hub by Miroslav Adzic 15-12-05
Oscillations and Regenerative Amplification using Negative ResistaWarning:nce Devicesby Ramon Vargas 15-12-05
Automatic Intruder Alarm by Ron J 15-12-05
Wart Zapper by Rev Thomas Scarborough 31-12-05
Doorphone Intercom page updated 27-2-06
RF Image Section updated 28-2-06
David Celestin's RF Amplifier added to RF Image Section 2-3-06
Vinyl Amplifier by Graham Maynard 2-3-06
Repeating Interval Timer by Ron J 2-3-06
Updated Disclaimer 2-3-06
Universal 4 Keypad Switch by Ron J 2-3-06
Motor Reversing Circuit schematic correction by Christian Sanchez 7-3-06
IR Extender Mk 5 updated with more fault finding tips and compatible handsets 8-3-06
AM Receiver page updated 20-6-06
Buffer Amplifier by Graham Maynard 23-6-06
Keypad Operated Switch No.2 by Ron J 23-6-06
Electronic Door Release by Ron J 23-6-06
Op-Amp Microphone Preamp 23-6-06
Hijack Alarm page updated and a new circuit by Ron J 23-6-06
Shed / Garage Alarm by Ron J 23-6-06
Gem Amplifier by Graham Maynard 23-6-06
2 Watt Amplifier page update 26-6-06
Medium Wave Active Antenna by David Sayles, schematic redrawn 26-6-06
Tone Control Circuit page updated 26-6-06
Universal Buffer Photograph Added 9-8-06
Gem Amplifier Updated text and 200W Schematic by Graham Maynard 9-8-06
An SCR Based Burglar Alarm by Ron J 11-11-06
Voltage Comaparator and Q Multiplier make a stable Sine Wave Oscillator (in PDF format) by Ramon Vargas 11-11-06
The Modern Armstrong Regenerative Receiver by Ramon Vargas 11-11-06
A Transistor Based Burglar Alarm by Ron J 20-3-07
New Links added 21-3-07
Broken Links fixed in Miscelleaneous Circuits 21-3-07
Mark 1/1A update with a picture of a finished version by Nick (UK)Warning:
PCB for Mark 5 IR Extender kindly made by Lubo Veselsky 21-3-07
Analysis and Aplications of the Capacitive Transformer (PDF Format) by Ramon Vargas 21-3-07
150W MP3 Car Audio Amplifier by Youssef Bouterfes 21-3-07
Infra Red TV Extender by Guy Bocquillon 21-3-07
Credit Page Updated 27-3-07
Interval Timer 2 by Ron J 20-7-07
Adjustable Power Supply with Charger by Milardo de Guzman 21-07-07
Computer Output Interface 21-7-07
The Best of Thomas Scarborough Book 1 is a PDF book containing circuits made from 6 components or less. Thomas has kindly made book 1 available to everyone as a free download. Available in the Practical Section
How to Create the Best Image in Circuit Maker by Youssef Bouterfes (in the CM Simulation Section). 26-7-07
24 Watt Class A Amplifier by Marc Klynhans 27-7-07
Some corrections and broken links fixed 4-1-08
One Time Only Alarm by Ron J 7-1-08
Battery Powered One Time Alarm by Ron J 7-1-08
Telephone In Use Indicator corrupted page restored 2-4-08
Led Flasher Corrupted page restored 2-4-08
Room Monitor 10-4-08
CMOS 4060 Alarm by Ron J 11-4-08
MK5 Infra Red Repeater modification by Allan Popplewell 11-4-08
Static Detector Circuit page updated 12-4-08
Links page Updated 14-4-08
Using ECM's page updated 14-4-08
Help Page updated
Function Generator Updated 20-4-08
Circuit Index Updated 26-04-08
New Links added 10-5-08
Audio Security Monitor 26-6-08
Hijack Alarm 3 by Ron J 26-6-08
30 Watt VHF Amplifier by David Celestin 26-6-08
Three Flashing LED Doorbells by Ron J 26-6-08
ECM Mic-Preamp Page Updated 2-7-08
6 Zone Alarm with Display 25-9-08
Media Page extended and updated 29-9-08
Temperature Monitor Updated 29-9-08
Schmitt Trigger Circuit 14-10-08
Circuit Index Updated 14-10-08
Article Index Updated 14-10-08
Antenna Tuning Unit 14-10-08
Sensitive DX TRF Receiver external link (Circuit 32) to Husnu Kokturk's web site 14-10-08
Correction to L200 PSU (pins 2 and 5 reversed) and datasheet added 27-10-08
Links Page Updated 1-11-08
BJT Bias Circuits Updated 2-11-08
Boosting Regulator Current Updated 3-11-08
1 hour timer circuit 23-12-08
49MHz Wlakie Talkie Circuit external link 23-12-08
IR Switch Page and diagram updated 30-1-09
DC Reversing Circuit Updated 31-1-09
Solid State Reversing Circuit Updated 31-1-09
Schematics Page redesigned 18-2-09
Timing Circuits Page redesigned 19-2-09
Monostable Timer Updated 19-2-09
All main menus and sections updated 21-2-09
LTspice New page added in Simulator section 21-2-09
LF Oscillator 21-2-09
Predicting Thermistor Resistance by Ron J in Analysis Section 23-3-09
Downloadable Thermistor Resistance Charts (bottom of page) by Ron J 23-2-09
Repeating Interval Timer New Vero Layout by Ron J 23-2-09
Toggle Switch No.1 by Ron J 23-2-09
1 Hour Timer 23-2-09
Thermostat with Adjustable Hysteresis by Ron J 23-2-09
Analysis and Design Page Updated 27-2-09
Schematic sections, Alarm, Audio, Timing , Switching Updated 7-3-09
Section RF and Power Circuits Updated 14-3-09
All Schematic sections, Miscellaneous, Control and Interface, Testgear now updated 23-3-09
Computer Virus Removal added to Media Section 27-3-09
EMF Probe Version 2 27-3-09
Solar Flasher by QS 27-3-09
Credits Page, Disclaimer and Viewers Gallery moved to Help Page 6-4-09
LF071 Mic Amplifier new text added 6-4-09
AM Receiver new text added 6-4-09
Links Page Updated 22-5-09
Toggle Switch No. 2 by Ron J 23-5-09
Sequential Timer by Ron J 23-5-09
Temperature Alarm Circuit modified 30-6-09
IC Pinouts Updated 14-6-09
6 Input Mixer Updated 15-7-09
Reduction of Detector Diode Losses in a Crystal Radio(Theory section) by Ramon Vargas 15-7-09
Optimization of the Signal Voltage of a Selectivity Enhanced Germanium Detector (Under Theory in PDF Format) by Ramon Vargas 15-7-09
Links Updated 5-9-09
Aerial Tuning Unit page updated 14-9-09
Latch Switch Added14-0-09
Resonant Circuits Updated 14-9-09
DX-ing and SW Link added to Media Section 14-9-09
Op-amp Astable Timer 14-9-09
AM Receiver Updated special thanks to David from Germany for his coil pictures 14-9-09
Circuit Images Gallery Updated 16-9-09
AC Switch circuit Added 16-9-09
SW Receiver Circuit Mod and Page Updated by Ramon Vargas 17-9-09
Download Page Updated 10-10-09
Winscope article Updated 19-10-09

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