There are 221 circuit schematics available in this category. Click here for all circuit diagrams. The Last circuit was added on Thursday, 3 September 2015.Please note some adblockers will suppress the schematics as well as the advertisement so please disable if the schematic list is empty.

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CircuitCategoryDate AddedOK?Votes 
Simple moisture indicatorMisc Status0 vote up vote down
Two-tone doorbell using 555 timerMisc Status0 vote up vote down
omentary High Voltage Arc Circuit - can be used to Ignite a barbeque or a Gas in a Potato GunMisc Status0 vote up vote down
Simple BFO metal detector using 2N3906 and 2N3904 transistorsMiscMay 30, 2007Status1 vote up vote down
Cat or Dog Detector - can be used to control entry on a Cat or Dog DoorMisc Status0 vote up vote down
Fish caller circuitMiscSep 23, 2009Status0 vote up vote down
Powerful stun gun / taser circuit diagramMiscSep 23, 2009Status-1 vote up vote down
Ultrasonic sound detector / snifferMiscSep 23, 2009Status0 vote up vote down
Air flow detectorMisc Status0 vote up vote down
Simple Frequency Reader for conversion VFOsMiscOct 05, 2009Status0 vote up vote down
Eddie's Composting Loo fan controllerMiscMar 09, 2012Status0 vote up vote down
Touch operated Band switch for Radio SetMiscOct 25, 2014Status0 vote up vote down
Digital Remote ThermometerMiscJun 26, 2009Status0 vote up vote down
Capacitive SensorMiscJun 26, 2009Status1 vote up vote down
Mains Remote-Alert - Remotely operates beeper and/or a LED via mains supply lineMiscJun 26, 2009Status0 vote up vote down
Touch activated switch using CD4011 CMOS NAND gateMiscJun 26, 2009Status0 vote up vote down
Voice activated switch (VOX) circuit diagramMiscJun 26, 2009Status0 vote up vote down
UltraSonic RadarMiscJun 26, 2009Status0 vote up vote down
Nocturnal Animals WhiskerMisc Status0 vote up vote down
Insect RepellantMiscSep 17, 2009Status-2 vote up vote down
Digital Radar SpeedometerMiscOct 21, 2009Status0 vote up vote down
Electromagnetic Field Probe with Meter Output using an LF351 opampMiscOct 19, 2009Status0 vote up vote down
Beat Balance Metal DetectorMisc Status0 vote up vote down
Coil Coupled Operation Metal DetectorMiscNov 10, 2009Status0 vote up vote down
Missing Pulse Detector Circuit with 555 ICMiscOct 03, 2013Status0 vote up vote down
Chaos generatorMiscJan 26, 2001Status0 vote up vote down
A Two-Way Morse Practice SetMisc Status0 vote up vote down
Voltage Comparator Information And CircuitsMiscApr 27, 2003Status0 vote up vote down
Visible and Infrared Light DetectorsMisc Status0 vote up vote down
Light Activated Detector Circuit (LM393/LM555)MiscSep 10, 2006Status0 vote up vote down
10 GHz CW Radar based on a X-band GunnplexerMisc Status0 vote up vote down
GoldPic 3 Pulse Induction Metal Detector (has electronic kit available)MiscMay 30, 2007Status0 vote up vote down
Photodiode primer and interface circuit diagrams including photovoltaic and photoconductive modesMiscMar 04, 2010Status0 vote up vote down
Full-duplex doorphone with 3 wires connectionMiscMar 23, 2003Status0 vote up vote down
G Strain energy absorberMiscJan 01, 2003Status0 vote up vote down
Amateur weather station to APRS interface ALWXI-01MiscOct 07, 2009Status0 vote up vote down
Switch debouncer circuits including transistor, CMOS logic and a 555 timer based designMiscJan 31, 2010Status0 vote up vote down
Interesesting circuits using diodes ideal for education or introductory courses on electronicsMiscFeb 20, 2010Status0 vote up vote down
Selection of run circuits to experiment with the 4017 CMOS decade counter chipMiscFeb 26, 2010Status0 vote up vote down
Variety of applications using a CMOS 4001 2-input NOR gate including a PCB layoutMiscFeb 20, 2010Status0 vote up vote down
Select of interesting electronic circuits that require only a single transistor ideal for educationMiscFeb 20, 2010Status0 vote up vote down
Small selection of useful circuitsMiscFeb 09, 2010Status0 vote up vote down
Marshmallow Bazooka with a PIC12F615 based capacitor discharge ignition systemMiscMay 16, 2010Status0 vote up vote down
Touch sensistive touchpad based on a PIC16F627A microMiscMay 24, 2010Status0 vote up vote down
Electric cockroach zapperMiscMay 24, 2010Status0 vote up vote down
Home-Built Magnetic LevitatorMisc Status0 vote up vote down
Project for experimenting with magnetic levitationMisc Status0 vote up vote down
FET based metal detector using MPF102 / J310 BF998 FETsMiscMay 30, 2007Status0 vote up vote down
Ultrasound detectorMiscSep 13, 2006Status0 vote up vote down
Build Your Own Video-Rate 2-photon MicroscopeMiscSep 25, 2009Status0 vote up vote down
Sony RS-422 ADAT sync cable pinoutMiscSep 10, 2006Status0 vote up vote down
Garmin Foretrex 101,201, Forerunner 101,201 to Serial DB9 cable schematic pinoutMiscSep 10, 2006Status0 vote up vote down
Simple DTMF Repeater Controller using PIC16F84Misc Status0 vote up vote down
Build a Simple Bat DetectorMiscJan 08, 2014Status0 vote up vote down
Capacitance to Voltage conversionMisc Status0 vote up vote down
Biasing Op-Amps into Class AMiscJan 01, 2003Status0 vote up vote down
Bleeper box for time referenceMiscMay 01, 2004Status0 vote up vote down
Random noise generatorMiscJan 26, 2001Status0 vote up vote down
Analog pulse counterMiscAug 12, 2001Status0 vote up vote down
Analog opto-isolatorMiscAug 12, 2001Status0 vote up vote down
Pulse width modulators (PWM)MiscAug 12, 2001Status0 vote up vote down
Pulse width to voltage converterMiscAug 12, 2001Status0 vote up vote down
Air flow detector using an incandescent lamp to detect airflowMisc Status0 vote up vote down
Simple Lie DetectorMiscSep 01, 2009Status0 vote up vote down
Low Voltage AlarmMiscSep 01, 2009Status0 vote up vote down
Rain DetectorMiscSep 01, 2009Status0 vote up vote down
Magnetic levitation deviceMiscAug 14, 2002Status0 vote up vote down
Tesla power receiverMiscJan 06, 2002Status0 vote up vote down
1.9 Kilojoule Coil GunMiscNov 16, 2010Status0 vote up vote down
A spark throwing tesla coil made entirely of garbageMiscNov 16, 2010Status0 vote up vote down
Basic Homebuilt Discrete DTL gate circuits (Diode Transistor Logic)Misc Status0 vote up vote down
Lazer Tag Equipment ModificationsMiscMar 23, 2003Status0 vote up vote down
Inexpensive APRS Weather StationMiscAug 14, 2002Status0 vote up vote down
Two-component metal detector using a 4093Misc Status0 vote up vote down
Induced voltage sensor delta-peak trigger for coilgunMisc Status0 vote up vote down
Open loop pulse trigger module for coilgunMisc Status0 vote up vote down
Optical speed trap to measure the the velocity of the projectileMisc Status0 vote up vote down
Optical trigger module for coilgunMisc Status-1 vote up vote down
Power MOSFET module for coilgunMisc Status0 vote up vote down
Three stage induced voltage triggered coilgunMisc Status0 vote up vote down
Thyristor fired coilgun circuit diagramMisc Status0 vote up vote down
Magnetic levitation project from Electronics Now, February 1996Misc Status0 vote up vote down
LNS Technologies Levitator Kit circuit diagramMisc Status0 vote up vote down
Magnetic levitation project from Popular Electronics, May 1966Misc Status0 vote up vote down
Magnetic levitation project from Popular Electronics, May 1989Misc Status0 vote up vote down
Barry's magnetic levitation projectMisc Status0 vote up vote down
Barry's Coilgun Mark I circuit diagramsMisc Status0 vote up vote down
Barry's Coilgun Mark II circuit diagransMisc Status0 vote up vote down
Barry's Coilgun Mark III circuit diagransMisc Status0 vote up vote down
Barry's Coilgun Mark IV circuit diagransMisc Status0 vote up vote down
Circuit diagram for Coilgun Pistol Pskov 1100Misc Status0 vote up vote down
1uS light pulse descriminator plus F to V converter (PDF)MiscJan 26, 2001Status0 vote up vote down
Broadband 2MHz optical fiber receiver (PDF)MiscJan 26, 2001Status0 vote up vote down
Modulated light receiver circuit (PDF)MiscJan 26, 2001Status0 vote up vote down
1uS light pulse receiver plus post amp (MISC)MiscJan 26, 2001Status0 vote up vote down
Broadband 5MHz optical fiber receiver (PDF)MiscJan 26, 2001Status0 vote up vote down
High-speed 75MHz light receiver (PDF)MiscJan 26, 2001Status0 vote up vote down
Basement doorbell beeper (PDF)MiscJan 26, 2001Status0 vote up vote down
Time to dust indicator - battery powered dust indicator (PDF)MiscJan 26, 2001Status0 vote up vote down
Low-power optical interrupter (PDF)MiscJan 26, 2001Status0 vote up vote down
Simple nitrogen spark generator (PDF)MiscJan 26, 2001Status0 vote up vote down
Simple DIY BFO metal detectorMiscJun 27, 2010Status0 vote up vote down
Op Amp Comparator with Hysteresis with SPICE simulationMiscMar 26, 2011Status0 vote up vote down
Op Amp Precision Half-wave Rectifier including SPICE simulationMiscMar 26, 2011Status0 vote up vote down
Single-Supply AC Inverting Op Amp amplifier with SPICE simulationMiscMar 26, 2011Status0 vote up vote down
Hacking the Hot Wheels Radar Gun - includes circuit of analog front endMisc Status0 vote up vote down
Ultrasonic transducer oscillator circuitMiscJan 26, 2001Status0 vote up vote down
Build logic gates using discrete partsMiscJan 26, 2001Status0 vote up vote down
Jacob's LadderMiscJan 26, 2001Status0 vote up vote down
Automatic Plant Irrigation System Circuit for Watering Plants without any Human Interference.MiscDec 07, 2014Status0 vote up vote down
Circuit for gold wafer cardMiscFeb 21, 2005Status0 vote up vote down
Nokia 3310 Lcd Thermometer using DS18B20MiscFeb 21, 2005Status0 vote up vote down
Lost keys finder using HCF4069MiscFeb 21, 2005Status0 vote up vote down
Lightning DetectorMiscFeb 21, 2005Status0 vote up vote down
Geomagnetic field detectorMiscFeb 21, 2005Status0 vote up vote down
Fogger smoke machine controllerMiscJan 26, 2001Status0 vote up vote down
Pulse Induction Metal Detector part 1 (PDF)MiscJun 27, 2010Status0 vote up vote down
Pulse Induction Metal Detector part 2 (PDF)MiscJun 27, 2010Status0 vote up vote down
Mobile APRS / GPS tracking systemMiscMay 01, 2004Status0 vote up vote down
GPS receiver support kitMiscMay 01, 2004Status0 vote up vote down
Dekatron circuit diagram - device used for dividing by 10 during the valve eraMiscOct 25, 2009Status0 vote up vote down
Circuit diagrams for making logic gates from discrete componentsMiscOct 25, 2009Status0 vote up vote down
Lightning detector circuit diagramMiscSep 08, 2009Status0 vote up vote down
Heathkit Groundtrack GR-1290 VLF metal detector circuit diagram and detector coil construction notesMiscJun 27, 2010Status0 vote up vote down
White's Surfmaster PI (pulse induction) metal detector schematic diagramMiscJun 27, 2010Status0 vote up vote down
6 Pole ElectroMagnet Motor (aka Simple Brushless motor)Misc Status0 vote up vote down
Solid State Tesla Coil and Wireless PowerMisc Status0 vote up vote down
Tesla coil construction projectMisc Status0 vote up vote down
Vareity of circuits for interfacing to/from TTL logicMisc Status0 vote up vote down
Dinsmore 1490 digital compassMiscNov 29, 2002Status0 vote up vote down
Geiger counter circuit diagramMiscNov 29, 2002Status0 vote up vote down
Electric field disturbance monitorMiscJan 26, 2001Status0 vote up vote down
Inexpensive seismometer projectMiscDec 15, 2002Status0 vote up vote down
Digg Button KitMiscOct 12, 2009Status0 vote up vote down
SIM card reader circuit diagramMiscOct 12, 2009Status0 vote up vote down
Circuit for driving a liquid crystal (LCD) shutter to simply pass or block lightMiscDec 21, 2009Status0 vote up vote down
Lie detectorMisc Status0 vote up vote down
Simple metal detector based on a PIC12F683 microcontrollerMiscJun 27, 2010Status0 vote up vote down
Three component bat detector based on a PIC12F683 microcontrollerMiscJun 27, 2010Status0 vote up vote down
Homemade GPS jammer using a MC145151 frequency synthesizerMiscJan 17, 2011Status-1 vote up vote down
2D3 Nixie clock schematic using Atmel microcontrollerMiscSep 13, 2006Status0 vote up vote down
Popular Electronics Ultrasound DetectorMiscJan 01, 2003Status0 vote up vote down
Navigator 555A radio direction finder (RDF) circuit diagramMiscMay 01, 2004Status0 vote up vote down
Touch switchesMiscMar 05, 2009Status0 vote up vote down
Build your own UFO Bino-Scope unit - upgrade binoculars to become a photosensitive bino-scopeMisc Status0 vote up vote down
Color sensor circuitMisc Status0 vote up vote down
PASCO scientific model SF-9211 stroboscope schematic (PDF)Misc Status0 vote up vote down
u-Blox GPS receiver boardMiscMar 23, 2003Status0 vote up vote down
Assorted digital circuitsMiscMar 18, 2003Status0 vote up vote down
Basic opamp circuitsMiscMar 18, 2003Status0 vote up vote down
Miscellaneous simple circuitsMiscMar 18, 2003Status0 vote up vote down
Simple electronic keyerMisc Status0 vote up vote down
FM Morse Code KeyerMisc Status0 vote up vote down
Easy Morse Code Keyer CircuitMisc Status0 vote up vote down
CW Tone KeyerMisc Status0 vote up vote down
Digital Call Sign AnnunciatorMiscJun 09, 2002Status0 vote up vote down
Monitor output from Motorola Oncore GPS engine in HP Z3801A in GPS Disciplined OscillatorMiscMay 01, 2004Status0 vote up vote down
Ultrasonic switch transmitter and receiver circuit diagramMiscJan 26, 2001Status0 vote up vote down
Plant Watering Watcher (moisture meter)Misc Status0 vote up vote down
A small collection of quick to build electronic circuit designsMisc Status0 vote up vote down
DIY Plasma Globe using an automotive ignition coilMisc Status0 vote up vote down
DIY Tesla coil - DC Powered with Plasma OutputMisc Status0 vote up vote down
StroboscopeMiscAug 17, 2009Status0 vote up vote down
Very basic circuitsMiscJan 26, 2001Status0 vote up vote down
Bat detectorMiscJan 26, 2001Status0 vote up vote down
Electronic canary doorbellMisc Status0 vote up vote down
Electronic dazerMisc Status0 vote up vote down
Jacob's LadderMisc Status0 vote up vote down
Negative Ion DetectorMisc Status0 vote up vote down
Negative Ion GeneratorMisc Status0 vote up vote down
Tesla coilMisc Status0 vote up vote down
Solid state tesla coilMisc Status0 vote up vote down
High voltage zappersMisc Status0 vote up vote down
Morse Code Practice Keyer 1MiscJan 26, 2001Status0 vote up vote down
Morse Code Practice Keyer 2MiscJan 26, 2001Status0 vote up vote down
741 Light SensorMiscJan 26, 2001Status0 vote up vote down
Fluid level detectorMiscJan 26, 2001Status0 vote up vote down
Touch switch using transistorsMisc Status0 vote up vote down
FCTS ProjectMiscMar 25, 2001Status0 vote up vote down
Count Accumulator for Radiation Levels (CARL)MiscSep 21, 2006Status0 vote up vote down
Modifications for CDV700 Geiger CounterMiscSep 21, 2006Status0 vote up vote down
The WB0RIO 6U8A Code Practice OscillatorMiscMay 19, 2015Status0 vote up vote down
Big Ear Stereo Parabolic MicrophoneMiscSep 21, 2006Status0 vote up vote down
Ultra Low Power LCD IndicatorMiscSep 21, 2006Status0 vote up vote down
Vacuum Tube B+ Delay CircuitMiscMay 19, 2015Status0 vote up vote down
12 Volt Toilet Tank Refiller circuit diagramMiscSep 21, 2006Status0 vote up vote down
Morse Code Beacon KeyerMiscJan 26, 2001Status0 vote up vote down
Weather station with pressure reading, relative humidity, indoor & remote temperature readingMisc Status0 vote up vote down
Induction receiver for tracing wiring behind walls, hearing lightning and other electric dischargesMisc Status0 vote up vote down
Texas Instruments collection of differential op-amp circuits (PDF)Misc Status0 vote up vote down
Texas Instruments collection of buffer op-amp circuits for ADCMisc Status0 vote up vote down
Building a Hardware Random Bit GeneratorMisc Status0 vote up vote down
Delayed shutter control for Kodak DC-20MiscJul 24, 2002Status0 vote up vote down
Morse code displayMiscJul 24, 2002Status0 vote up vote down
Circuit for temperature stabilization of a MTP3055E MOSFETMiscSep 01, 2009Status0 vote up vote down
Kenwood TH-D7 NMEA GPS bug fixMisc Status0 vote up vote down
Doorbell for the deaf that provides a delayed visual indication when a doorbell switch is pressedMiscNov 27, 2002Status0 vote up vote down
Electromagnetic field detectorMiscJan 26, 2001Status0 vote up vote down
Insect Repellant (22KHz audio oscillator)MiscNov 27, 2002Status0 vote up vote down
High Quality IntercomMiscNov 27, 2002Status0 vote up vote down
Magnetic Gun.MiscNov 27, 2002Status0 vote up vote down
Single chip metal detecor with a range of a few inches based on CS209AMisc Status0 vote up vote down
Static Electricity / Negative Ion DetectorMiscNov 27, 2002Status0 vote up vote down
Ultrasonic dog whistleMiscJan 26, 2001Status0 vote up vote down
Scaling ADXL50 accelerometer outputMiscJan 26, 2001Status0 vote up vote down
Infrasound circuits including several infrasound amplifier circuit diagramsMiscJul 05, 2015Status0 vote up vote down
Ghost detector - detects if a ghost disturbs the electric field in the vicinity of the deviceMiscJul 10, 2015Status0 vote up vote down
Lightning detector to receive static pulses from lightning at a frequency near 200 kHzMiscJul 10, 2015Status0 vote up vote down
Atmospheric receiver to detect crackling static in a radio produced by lightningMiscJul 10, 2015Status0 vote up vote down
Powerful buzzer for use as a doorbell or to notify others in different rooms dinner is ready etcMiscJul 15, 2015Status0 vote up vote down
Powerful Security Siren - Transistors based and operates from 12V power supplyMiscJul 15, 2015Status0 vote up vote down
Whistle Responder - Beeps when hears your whistle, A gadget suitable for key-holders, games etc.MiscJul 22, 2015Status0 vote up vote down
Water Level Indicator Using 7-Segment DisplayMiscJul 30, 2015Status0 vote up vote down
Rainwater Storage GaugeMiscJul 30, 2015Status0 vote up vote down
Cat and Dog RepellerMiscJul 30, 2015Status0 vote up vote down
Inexpensive Remote Watering SystemMiscJul 30, 2015Status0 vote up vote down
You Have Mail! Letterbox monitoring systemMiscJul 30, 2015Status0 vote up vote down
Environmentally-friendly Mosquito RepellerMiscJul 30, 2015Status0 vote up vote down
Doorbell Memory Circuit DiagramMiscJul 30, 2015Status0 vote up vote down
Plant Watering Watcher Circuit SchematicMiscJul 30, 2015Status0 vote up vote down
Salt Taster Circuit DiagramMiscJul 30, 2015Status0 vote up vote down