In this article we’ll study a digital stopwatch design configured around the very popular IC LM555 in conjunction with a 4-digit counter IC with multiplexed 7-segment output drivers (MM74C926). Written and Submitted by: Jennifer Goldy Circuit Operation IC MM74C926 is internally made up of a 4-digit counter, an output latch up stage, a npn output […]
Newly Updated Circuit Projects:
7 Interesting IC 555 Siren and Alarm Circuits
In this post I have explained how to use IC 555 to create 7 interesting siren and alarm sound effect generator circuits. The versatile astable multivbrator configuration of IC 555 allows us to implement it for making various types of sirens and alarm circuits. This becomes possible because an astable is basically a waveform generator, […]
Grid Mains to Generator Changeover Relay Circuit
In this post I have explained a simple configuration which can be used as a automatic changeover circuit for switching AC grid mains to generator mains, during power failures or outages. The explained circuit will effectively switch the connected appliances to the generator mains during power failure however it won’t be able to switch start the generator automatically, […]
Simple Crystal Tester Circuit
In this post I have explained how to build a simple crystal tester circuit using ordinary parts like transistors, resistors, diodes and capacitors. What is a Crystal A crystal can be used for making an electronic oscillator circuit by using the mechanical resonance of a piezoelectric vibrating crystal to generate an electrical frequency having a […]
5 Simple Motion Detector Circuits using PIR
A PIR motion sensor alarm is a device which detects the infrared radiation from a moving human body and triggers an an audible alarm. In this post I have explained 5 simple motion detector circuits using op amp and transistor. We also discuss the pinout details of the standard passive infrared (PIR) sensor RE200B. We […]
Convert a Square Wave Inverter into a Sine Wave Inverter
In this post I have explained a few circuit concepts which can be employed for converting or modifying any ordinary square wave inverter to sophisticated sine wave inverter design. Before studying the various designs I have explained in this article, it would be interesting to know the factors which typically makes a sine wave inverter […]