| Circuit | Category | Date Added | OK? | Votes | |
| RCM710 electronic scale, technical manual including schematic | Test | Apr 12, 2001 |  | 2 |
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| Ground Fault Indicator | Test | | | -4 |
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| Sound pressure level meter | Test | Sep 23, 2009 | | -1 |
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| True RMS Watt Meter | Test | Sep 23, 2009 | | -1 |
|
| The u-counter, a PIC based programmable frequency meter (PDF) | Test | Oct 05, 2009 | | 2 |
|
| Ultra-simple Voltage Probe | Test | Jun 26, 2009 | | 1 |
|
| Wire tracer | Test | | | -3 |
|
| IR Remote Control Tester | Test | Jul 05, 2012 | | -1 |
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| Digital Voltmeter using ICL7107 | Test | Sep 17, 2009 | | -4 |
|
| Beeper to find short circuits | Test | Oct 19, 2009 | | -2 |
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| Led display digital Voltmeter using ICL7107 | Test | Sep 17, 2009 | | 0 |
|
| MOSFET transistor tester | Test | Nov 05, 2009 | | -6 |
|
| Oscilloscope testing module (huntron circuit) | Test | Nov 10, 2009 | | 2 |
|
| Logic probe | Test | Oct 19, 2009 | | 0 |
|
| Pulse Reading Logic Probe | Test | Oct 19, 2009 | | 0 |
|
| Stereo Test Tone Generator | Test | Oct 21, 2009 | | -2 |
|
| Continuity Tester based on 4 x 2N3904 and 1 x 2N3905 transistors | Test | Oct 19, 2009 | | 0 |
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| Audible Logic Probe based on LM339 operational amplifier | Test | Oct 19, 2009 | | 0 |
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| Single chip digital voltmeter using ICL7129 | Test | Nov 05, 2009 | | -1 |
|
| Latching Continuity Tester to help find intermittent faults, has quite a few innovative features | Test | Oct 19, 2009 | | 1 |
|
| Linear Resistance Meter | Test | Oct 19, 2009 | | -4 |
|
| XTal Tester for testing quartz crystals based on a pair of BC550C PNP transistors | Test | Oct 19, 2009 | | -1 |
|
| Self-powered Fast Battery-Tester - Tests 1.5 to 15 Volt cells | Test | Sep 17, 2009 | | 0 |
|
| Microphone polarity tester circuit diagran | Test | Apr 14, 2010 | | -2 |
|
| Low-Drift High-Impedance JFET DC Voltmeter | Test | Jan 08, 2014 | | -2 |
|
| Resistor decade box | Test | Aug 14, 2002 | | -2 |
|
| Simple test equipment to build | Test | | | -2 |
|
| RF Power Meter for the QRP measures up to 25 watts | Test | | | 3 |
|
| Dip Oscillator for HF | Test | | | 1 |
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| High Impedance Voltmeter | Test | Sep 10, 2006 | | -1 |
|
| Servo Motor Test Circuit (LM555) | Test | | | 0 |
|
| Frequency counter based on PIC16F628 and LCD display | Test | Jun 19, 2011 | | -4 |
|
| 220V live wire-in-wall scanner | Test | Mar 23, 2003 | | -2 |
|
| KD1JV Digital SWR / Power Meter | Test | Apr 12, 2014 | | 0 |
|
| Low Power Antenna Analyzer and ATU Tuning Aid | Test | | | -1 |
|
| Fixed Frequency "Tuner Dipper" | Test | | | -3 |
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| Universal frequency counter & voltage meter | Test | Oct 07, 2009 | | 0 |
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| ESR Meter | Test | May 17, 2002 | | -2 |
|
| Line Output / Flyback transformer tester | Test | May 17, 2002 | | 1 |
|
| PCB board tester and RF detector circuir diagrams | Test | Feb 09, 2010 | | -1 |
|
| Alarm circuit to remind you to turn off your DMM (digital multimeter) | Test | Jan 31, 2010 | | -1 |
|
| Function generator based on 555 timer and three 2N2222 transistors | Test | Feb 05, 2010 | | -3 |
|
| Multi-trace scope display that allows up to 4 channels to be viewed on a single oscilloscope channel | Test | Feb 26, 2010 | | -1 |
|
| DDS from 1-60 MHz with built-in amplifier and variable output level using Analog Devices AD9851 | Test | | | -2 |
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| Isolated oscilloscope probe | Test | May 16, 2010 | | -1 |
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| Superprobe handheld test device based on a PIC16F870 | Test | May 24, 2010 | | 2 |
|
| Build an inexpensive Hall effect Gaussmeter | Test | | | -1 |
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| Design for a slightly more expensive Gaussmeter | Test | | | -1 |
|
| VCR head amplifier tester | Test | May 25, 2012 | | -1 |
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| Conrad Electronics MM3610D multimeter cable pinout | Test | Sep 10, 2006 | | -2 |
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| Audio Millivoltmeter | Test | Apr 14, 2010 | | 0 |
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| Microphone Circuit Test Oscillator | Test | Apr 14, 2010 | | 0 |
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| Distortion analyser circuit diagram | Test | Apr 14, 2010 | | -2 |
|
| The ESP SIM (Sound Impairment Monitor) | Test | Apr 14, 2010 | | -2 |
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| Linkwitz Cosine Burst Generator | Test | Apr 14, 2010 | | 0 |
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| Amplified field strength meter / RF sniffer | Test | Apr 14, 2011 | | -2 |
|
| 3 in one tester (audio, tone generator, diode/circuit tester) | Test | | | -3 |
|
| In-circuit electrolytic capacitor checker | Test | Mar 27, 2009 | | -2 |
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| Logic probe with pulser | Test | Mar 27, 2009 | | -2 |
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| Electric field & leakage detector | Test | Aug 12, 2001 | | -2 |
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| Simple Polarity Tester | Test | Sep 01, 2009 | | -1 |
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| 20kV Digital High Voltage Meter | Test | Nov 16, 2010 |  | 1 |
|
| Filter Choke Analyzer | Test | Apr 10, 2014 | | -1 |
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| A Load Box for testing power supplies | Test | Apr 10, 2014 | | -2 |
|
| Low resistance adapter for a DMM (digital multimeter) | Test | Apr 10, 2014 | | 0 |
|
| Miniature SWR / RF power meter circuit | Test | Feb 15, 2014 | | -2 |
|
| Schematics and C code for a PIC frequency counter operating up to about 50 MHz (7 segment) | Test | | | -1 |
|
| Schematics and C code for a 0-5V PIC LCD volt meter | Test | | | 0 |
|
| Schematics and C code for a PIC frequency counter operating up to about 50 MHz (LCD) | Test | | | -1 |
|
| Not So Tiny Power Meter - Measures power consumption for entire apartment
Not So Tiny Power Meter | Test | Feb 21, 2013 | | -1 |
|
| LED based transistor tester
LED based transistor tester | Test | Oct 05, 2012 | | -1 |
|
| TTL pulse counter/logic probe | Test | | | -3 |
|
| Transistor Tester | Test | Nov 13, 2010 | | 0 |
|
| Wire Tracer (Receiver) | Test | Nov 13, 2010 | | 0 |
|
| Wire Tracer (Transmitter) | Test | Nov 13, 2010 | | 0 |
|
| Elecraft XG2 receiver test oscillator (PDF) | Test | Sep 13, 2006 | | -1 |
|
| Contactless Mains Voltage Indicator | Test | | | -1 |
|
| Mini tester: Handles continuity testing, resistor testing, capacitor testing and diode testing | Test | | | 1 |
|
| Precision audio millivoltmeter | Test | Feb 21, 2005 | | -4 |
|
| PIC16F84 based diode tester | Test | Feb 21, 2005 | | -2 |
|
| Continuity tester using transistors | Test | Feb 21, 2005 | | -2 |
|
| Latching continuity tester using 4093 | Test | Feb 21, 2005 | | -1 |
|
| Linear Resistance Meter | Test | Feb 21, 2005 | | -2 |
|
| Crystal tester circuit diagram | Test | Feb 21, 2005 | | 0 |
|
| Capacitance meter | Test | Feb 21, 2005 | | 1 |
|
| Digital voltmeter (DVM) | Test | Feb 21, 2005 | | -1 |
|
| Transistor tester using 555 timer and 4027 | Test | Feb 21, 2005 | | -3 |
|
| Function generator based upon 8038 waveform generator IC | Test | Feb 21, 2005 | | 0 |
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| Picoammeter circuit schematic with 4 ranges using CA3420 | Test | Feb 21, 2005 | | -2 |
|
| Beeper to find short circuits (continuity tester) | Test | Feb 21, 2005 | | 1 |
|
| MOSFET tester for N-type MOSFET transistors | Test | Feb 21, 2005 | | -1 |
|
| Inductive meter adapter to measure inductance using a frequency counter | Test | Feb 21, 2005 | | -1 |
|
| Crystal tester that covers a range of 32kHz to 24MHz | Test | Feb 21, 2005 | | -2 |
|
| Oscilloscope testing module (Huntron circuit) that shows Lissajous patterns | Test | Feb 21, 2005 | | -1 |
|
| Logic probe with 7-segment display based on 74LS00 and 74LS47 | Test | Feb 21, 2005 | | -1 |
|
| Simple light sensor adapter for oscilloscope | Test | Jan 26, 2001 | | -1 |
|
| TDR cable reflection tester (Time Domain Reflectometer) | Test | Sep 21, 2006 | | 0 |
|
| Soft Power On Tester for Amplifiers | Test | Jan 29, 2010 | | 0 |
|
| TXTVb - 70cm ATV Test Generator (PDF) | Test | | | -1 |
|
| BCD readout frequency counter | Test | Aug 18, 2009 | | -1 |
|
| LCD Frequency Counter | Test | Aug 18, 2009 | | 0 |
|
| Panel Mounting Radio Frequency Counter | Test | Aug 18, 2009 | | -1 |
|
| Simple Frequency Counter | Test | Aug 18, 2009 | | -1 |
|
| Heathkit signal generator user manual and circuit diagram | Test | Oct 25, 2009 | | -1 |
|
| Spectrum analyzer Mk 1 | Test | Aug 18, 2009 | | 3 |
|
| Spectrum analyzer Mk 2 | Test | Aug 18, 2009 | | 1 |
|
| Z80 controlled Viscometer project | Test | Aug 18, 2009 | | 0 |
|
| Field Strength Meter (FSM) covers 2Mhz - 1Ghz with peak reception at 3-200Mhz | Test | | | 0 |
|
| UHF signal generator | Test | | | 0 |
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| VHF signal generator | Test | | | 0 |
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| -20 dB Couplers for use with a with a spectrum analyzer or other sensitive detector | Test | | | 0 |
|
| -20 dBm, 14.060 MHz Precision Signal Source | Test | | | 0 |
|
| Precision VXO for Crystal Characterization & Matching | Test | | | 0 |
|
| Return Loss Bridge | Test | | | -1 |
|
| Mini oscilloscope based on PIC18F4620 and standard 16x2 text LCD display module | Test | Jun 27, 2010 | | 2 |
|
| AD9850 DDS daughterboard | Test | Sep 21, 2006 | | 0 |
|
| Signal Tracer and Injector | Test | Sep 13, 2006 | | -2 |
|
| TDS/PPM Meter for measuring of the amount of salts in a solution | Test | Mar 29, 2009 | | 0 |
|
| Homebrew signal generator tunable from 3 to 30 Mhz | Test | Oct 08, 2009 | | 0 |
|
| Precision Frequency Marker | Test | | | 1 |
|
| Simple Inductance Meter | Test | | | 0 |
|
| VCR Tuner Based RF Spectrum Analyzer Schematic | Test | Sep 21, 2006 | | 0 |
|
| LCD frequency counter (PIC16F84) | Test | Nov 29, 2002 | | 1 |
|
| Simple electronic S meter | Test | | | 0 |
|
| Standalone LED tester | Test | Nov 02, 2010 | | 0 |
|
| Fluke 8010 / 8012 Interface | Test | Sep 25, 2009 | | 0 |
|
| UTP Cable Tester | Test | Sep 25, 2009 | | -2 |
|
| 10Hz - 100KHz D.D.S. Function Generator | Test | Sep 21, 2006 | | 0 |
|
| 555 Timer IC Tester circuit diagram | Test | Jan 26, 2001 | | 1 |
|
| 555 go / no-go tester circuit diagram | Test | Jan 08, 2002 | | -1 |
|
| Battery Tester for 1.5 and 9V | Test | | | 1 |
|
| Continuity tester V2 circuit diagram | Test | Jan 26, 2001 | | 0 |
|
| Continuity tester circuit diagram | Test | Jan 26, 2001 | | 0 |
|
| Logic probe | Test | Jan 26, 2001 | | -1 |
|
| Simple pH Meter Circuit, A Low Cost Adapter for Your Digital Voltmeter | Test | Nov 02, 2010 | | 0 |
|
| TTL Pulse Reading Logic Probe | Test | Sep 21, 2006 | | 0 |
|
| Stereo Test Tone Generator | Test | Sep 21, 2006 | | 0 |
|
| Octopus Curve Tracer | Test | May 19, 2015 | | -1 |
|
| Pulse Reading Logic Probe | Test | Jan 26, 2001 | | 0 |
|
| LC meter with LCD display for readout | Test | | | 0 |
|
| An ESR Meter For Electrolytic Capacitors (and Low Ohms Meter) | Test | Jun 24, 2015 | | -2 |
|
| Build your own Q Meter project | Test | Jun 24, 2015 | | 1 |
|
| A Simple RF Probe For Your DVM | Test | Jun 24, 2015 | | 1 |
|
| An RF Voltmeter for Transceiver Servicing | Test | Jun 24, 2015 | | -1 |
|
| Medium and Very High Quality Two Tone Generators for Transceiver Testing | Test | Jun 24, 2015 | | -1 |
|
| Highly sensitive and selective Field Strength Meter system | Test | Apr 14, 2011 | | 0 |
|
| Wide dynamic range Field Strength Meter mark I | Test | Apr 14, 2011 | | 0 |
|
| Wide dynamic range Field Strength Meter mark II | Test | Apr 14, 2011 | | 0 |
|
| Digital Wattmeter, measures from nanowatts to kilowatts using AD8307, PIC16F876, LCD Display | Test | | | 0 |
|
| SWR Bridge 1 to 1000 Mhz (1GHz) | Test | | | -1 |
|
| Field strength meter for the 137 kHz band | Test | May 01, 2004 | | 0 |
|
| Multi wire cable tester that handles up to eight conductors | Test | Nov 27, 2002 | | 0 |
|
| Connection tester for checking solder joints and other connections | Test | Nov 27, 2002 | | 0 |
|
| EMF field probe (electromagnetic field probe) covering up to 100kHz | Test | Jan 26, 2001 | | 0 |
|
| Function generator based on 8038PCD function generator IC | Test | Jan 26, 2001 | | 0 |
|
| Zener diode tester based on a 555 timer | Test | Jan 26, 2001 | | 1 |
|
| Accurate Digital LC Meter based on a PIC16F84 | Test | Feb 20, 2013 | | 0 |
|
| Pulse Generator And Signal Tracer Circuit Diagram | Test | Jul 22, 2015 | | 1 |
|
| The Curious C-Beeper - a probe beeps at a frequency that varies with capacitance | Test | Sep 03, 2015 | | 1 |
|
| DIY Digital AC Watt Meter | Test | Sep 30, 2015 | | -2 |
|
| Relative Field Strength Meter For A DMM | Test | Oct 06, 2015 | | 1 |
|
| Logic Probe With Sound | Test | Oct 06, 2015 | | 0 |
|
| DIY 4-Digit LED Digital Voltmeter Module based on ATmega8 | Test | Jul 03, 2016 | | 0 |
|
| RF Power Calibrator | Test | Jul 24, 2016 | | 0 |
|
| TDR Test System - WA0PIA | Test | Jul 24, 2016 | | 2 |
|
| Satellite Finder | Test | Jul 24, 2016 | | -3 |
|
| Simple Crystal Tester - F5JTZ | Test | Jul 24, 2016 | | 2 |
|
| L-C-R Bridge - G3BIK | Test | Sep 07, 2016 | | 0 |
|
| 1MHz-step Harmonic Marker Generator | Test | Sep 07, 2016 | | 1 |
|
| Logic IC Tester with PC Parallel Port Interface - using 8255 Interface IC | Test | May 01, 2015 | | -1 |
|
| 50 kHz to 70 MHz Spectrum Analyzer - K7TAU | Test | Sep 28, 2016 | | 0 |
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| Spectrum Analyzer on the Oscilloscope | Test | Sep 28, 2016 | | 2 |
|
| 0 to 60 MHz Spectrum Analyzer - WB5IPM | Test | Sep 28, 2016 | | -1 |
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| Spectrum Analyzer using TV-Tuner - W6WTU | Test | Sep 28, 2016 | | 1 |
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| 1 GHz Spectrum Analyzer Front-End | Test | Sep 28, 2016 | | 0 |
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| 100 MHz Spectrum Analyzer - W6URH | Test | Sep 28, 2016 | | -1 |
|
| 0 - 100 MHz Spectrum Analyzer Tracking Generator - W6URH | Test | Sep 28, 2016 | | 0 |
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| Panoramic Spectrum Analyzer for HF Receivers - WA6NCX | Test | Sep 28, 2016 | | 0 |
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| TV Tuner Spectrum Analyzer - WA2PZO | Test | Sep 28, 2016 | | 0 |
|
| 20 MHz to 600 MHz Spectrum Monitor | Test | Sep 28, 2016 | | 0 |
|
| IF for TV-Tuner for Spectrum Analyzers - AA4FB | Test | Sep 28, 2016 | | 0 |
|
| 200 MHz Spectrum Analyzer | Test | Sep 28, 2016 | | 3 |
|
| 45 MHz to 2050 MHz Spectrum Analyzer | Test | Sep 28, 2016 | | -3 |
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| Build an Analog Bar Graph Expanded Scale Voltmeter | Test | Oct 15, 2016 | | 0 |
|
| Build an LED Bargraph Optical Tachometer | Test | Oct 15, 2016 | | 1 |
|
| RF Sweeper - VK2ZAY | Test | Oct 17, 2016 | | 2 |
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| Zener Diode Emulator - WA5EKA | Test | Oct 20, 2016 | | 2 |
|
| Two chips LED Frequency Counter - PA2OHH | Test | Oct 20, 2016 | | 1 |
|
| High-Impedance RF Probe | Test | Oct 22, 2016 | | 2 |
|
| Time Domain Reflectometry Generator - PA3DSC | Test | Oct 22, 2016 | | 5 |
|
| 1 GHz Test Oscillator BFP450 | Test | Oct 29, 2016 | | 1 |
|
| Precision Voltage Reference for Multimeter Calibration | Test | Oct 29, 2016 | | 0 |
|
| DIY LAN Cable Tester | Test | Oct 29, 2016 | | -2 |
|
| 40MHz-Frequency counter with ATmega8 | Test | Sep 30, 2022 | | 0 |
|