This article discusses a simple ultrasonic sound sensor alarm circuit which may be appropriately set for detecting sound pressures well above the normal human listening capacity, that may range from 20 kHz and over. Ultrasonic Concept Ultrasound or ultrasonic sound waves was probably invented even before humans existed on this planet by a few of […]
Simple
Simple Digital Stopwatch Circuit (4-Digit)
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 […]
Simple Digital Clock using LM8650 IC Circuit
The digital time clock explained here is a circuit which most electronic amateurs would love to make. You might have heard about digital clocks made from clock ICs such as the popular LM8361, MM5387 etc but these ICs could be today quite obsolete and/or complex to build. Circuit Operation The present design is much easier […]
Simple Cellphone Jammer Circuit
This is a RF jammer designed for the U.S. 800 MHz cellular phone band (870-895 MHz). This works by generating an overwhelming sweeping RF carrier on the cell phone handset’s operating frequency range. Circuit Operation An Exar XR2206 Multi-purpose Generator is going to function as the triangle wave generator for supplying the sweep part of […]
Make this Simple Music Box Circuit
This simple circuit can be used to emulate the operation of a music box. The number of notes may be limited to 10 at the most, and therefore is capable of generating a simple melody. By: Akanksha Rathode Circuit Operation The circuit uses two popular integrated circuits: The timer 555 and 4017 decade counter Operation […]
Simple Thermostat Circuit Using Transistors
The electronic thermostat explained here can be used to control the room temperature by appropriately switching (turning on and off) a heating device. By: R.K. Singh Operational details of electronic thermostat The circuit employs a thermistor NTC (negative temperature coefficient) as the sensor device. – As long as the ambient temperature stays higher than the […]