There are 94 circuit schematics available. Last circuit added on Tuesday, 19 May 2015.

CircuitCategoryDate AddedOK?
Egg timer circuit diagram, PCB layout and assembly informationTiming 
Digital Clock with Alarm Using DS1307TimingMar 25, 2009
Digital timer with 7-segment display and pushbuttonsTimingMar 25, 2009
Simple Sine Wave Oscillator including a PCB layoutTimingSep 23, 2009
Direct Digital Synthesis VFO for HF Bands - based on Analog Devices AD7009 DDS (PDF)TimingOct 05, 2009
Continuous Coverage V.F.O. for H.F. (PDF)TimingOct 05, 2009
PCB exposure countdown timer based on an Atmel ATtiny2313TimingJun 28, 2011
Countdown timer with relayTimingAug 09, 2002
Long Time Period Automatic TimerTimingOct 25, 2014
Trangular wave generatorTimingMar 23, 2015
Triangle / Squarewave Generator using a 1458 dual opampTimingOct 21, 2009
3 - 12 MHz Signal GeneratorTiming 
Signal Frequency Beat Frequency OscillatorTiming 
Wide-swing Variable Crystal OscillatorTiming 
CA4060B Timer CircuitsTimingSep 10, 2006
Special Function Timer Circuits (LM555)TimingSep 10, 2006
10MHz GPS disciplined frequency standardTimingJun 19, 2011
Simple WWV receiver for 10 MHz calibration signalTimingApr 12, 2014
DDS/PLL based VFO synthesizerTimingOct 07, 2009
Timer circuit based on a 14536 and 4011 CMOS chips that can be calibrated using a frequency counterTimingJan 31, 2010
Audible timer that can be used as a cooking timer for roasting peanuts for exampleTimingJan 31, 2010
Selection of 14 oscillator circuits include sinewave, audio, logic and LED flashersTimingFeb 20, 2010
Function Generator Sine / Triangle / Square / Saw / Burst Sweep Noise based on PIC16F870TimingMay 16, 2010
455KHz oscillator using FET and 455KHz IF transformerTimingMay 25, 2012
Build a synchronous clock locked to the mains frequencyTimingAug 18, 2009
AF variable frequency generator using 555 ICTiming 
Crystal switcher using diodesTiming 
IC oscillator 1...30MHz using 74LS04 chipTiming 
Simple AF-oscillator / signal generator using pair on 2N2222 transistorsTiming 
Digital clock based on 74 series logicTiming 
Two nixie display clockTiming 
VFD (vacuum flourescent display) clockTiming 
Single-digit Nixie clockTiming 
Oscilloscope CRT ClockTiming 
Weston Voltmeter ClockTiming 
Binary clock using LED matrix to display a binary clock with 6 digits of 4 binary bits eachTiming 
Digital clock that receives and displays the time from the Rugby MSF radio transmission (PIC16F877)Timing 
Line powered 60Hz clock generator (PDF)TimingJan 26, 2001
Micro-power pulse generator (PDF)TimingJan 26, 2001
Divide by 1.5 counter (PDF)TimingJan 26, 2001
High-output square wave generator (PDF)TimingJan 26, 2001
D Flip-flot one-shot circuits (PDF)TimingJan 26, 2001
Equivalent circuit and SPICE model of 555 timerTimingApr 11, 2011
Op Amp Triangle-Wave Generator circuit diagram and SPICE simulation filesTimingJan 17, 2011
Wien Bridge Oscillator with SPICE simulationTimingMar 26, 2011
Clock dividerTimingJan 26, 2001
Clock doublerTimingJan 26, 2001
CMOS oscillator using 74C14 inverting Schmitt triggerTimingJan 26, 2001
Crystal 32.768KHz CMOS OscillatorTimingJan 26, 2001
Crystal oscillator using a CMOS or HCMOS inverterTimingJan 26, 2001
Cheap 40KHz clock using one gate of a 74C14TimingJan 26, 2001
Astable 40KHz clockTimingJan 26, 2001
'Rounding Off' a square waveTimingJan 26, 2001
Switch debounce using 555TimingJan 26, 2001
Square wave to sine wave converterTimingJan 26, 2001
Triangle / Square wave generatorTimingFeb 21, 2005
Binary clock circuit diagramTimingAug 18, 2009
Experimental DDS frequency synthesizer uses the AD9851TimingOct 08, 2009
LED matrix clock circuit diagramTimingAug 18, 2009
Giant nixie clock circuit diagramTimingAug 18, 2009
Panel-mounting clock circuit diagramTimingAug 18, 2009
Sidereal clock project with circuit diagramsTimingAug 18, 2009
Simple Function Generator using TL084 or other opampTiming 
Micropower pulse generator (PDF)TimingJan 26, 2001
Simple GPS Stabilised 10 MHz OscillatorTiming 
xTimer V1.0 a 4-Channel Timer based on a 89C4051 + MAX7219 display driverTimingApr 22, 2014
xTimer using CMOS shift register 4094 for driving 7-segment LED directlyTimingApr 22, 2014
Ice Tube Clock - Vacuum fluorescent display (VFD) clockTimingOct 12, 2009
DCF-77 PIC LED clock (DCF77 is the name of a German radio station on 77.5 KHz)TimingJun 27, 2010
DCF77 PIC16F84A Single-Nixie clock (DCF77 is the name of a German radio station on 77.5 KHz)TimingJun 27, 2010
24" Wall ClockTiming 
Astable Multivibrator Projects / Circuit diagramsTiming 
Tuning VFOs With A PN-JunctionTiming 
Sleep TimerTiming 
Super VXOTiming 
High Precision GPS/TV controlled Reference OscillatorTimingMay 01, 2004
TV based Receiver for a Standard Frequency GeneratorTimingMay 01, 2004
AD9852 DDS schematicTimingFeb 14, 2003
Decimal DDS Signal GeneratorTiming 
Build A 100Khz Crystal CalibratorTiming 
Crystal heater / temperature stablization circuit (TXCO)Timing 
A GPS receiver based frequency standardTimingMar 23, 2003
Long duration timer using 4060 12-stage binary ripple counterTimingAug 17, 2009
Clock generatorTimingJan 26, 2001
555 Timer Tutorial + CircuitsTimingJan 26, 2001
All-Ears QSK Timing GeneratorTimingMay 19, 2015
Monostable multivibratorTimingJan 01, 2003
GPS-based universal clock generatorTiming 
Homemade scope clock using a DG7 tube and a Microchip PIC16F876Timing 
VCO covers 300MHz to 500MHz based on Maxim MAX2608 VCOTiming 
Push Button Switch DebouncerTimingJan 26, 2001
Square wave oscillator using CMOS 4011 NAND chipTimingJan 26, 2001
5 to 30 Minute Timer circuit diagramTimingNov 27, 2002
NE555 Basic MonostableTimingNov 27, 2002