In this article I have explained how to build a simple bicycle speedometer circuit which can be used to measure the speed of the bicycle. Video Demonstration What is a Bicycle Speedometer, How it Works Bicycle speedometer is a device which checks the rotation per minute of the bicycle wheel and displays the results over […]
Meters and Testers
Stud Finder Circuit – Find Hidden Metals Inside Walls
A stud finder is an electronic device specially created for scanning concrete walls and locating metallic objects, such as nails, bolts, pipes, hidden beneath the wall. In the following post I have explained a very simple two-transistor metal detector that you can assemble in an afternoon or two and have fun with using for hours […]
Semiconductor Tester Circuit [LED, Transistor, SCR Tester]
The semiconductor tester circuit I have explained below performs continuity tests on SCRs, bipolar transistors, and diodes. How the Circuit Works A squarewave oscillator with a frequency of about 350 Hz is produced by a couple of IC 4049 gates, U1a along with U1b, R1, R2, and C1. The complementary outputs required for testing both NPN and […]
6 Simple Capacitance Meter Circuits Explained – Using IC 555 and IC 74121
In this post I will talk about 6 easy yet accurate capacitance meter circuits using the ubiquitous IC 555 and many other easily available ICs. How Capacitors Work Capacitors are one of the main electronic components which come under the passive component family. These are extensively used in electronic circuits and virtually no circuit can […]
AC Millivolts Meter Circuit Using IC 741
In this article we study an op amp based millivolt meter circuit designed to measure AC millivolts accurately, I have explained the details from the following explanation. The circuit shown below can be used to measure DC potentials in the range of milli-volts. The circuit is highly sensitive and is calibrated to measure voltages in […]
Simple IC Tester Circuit [Test Digital and Analogue ICs]
The IC Tester is simple to use. You don’t have any switches to configure or lengthy test processes to complete. The universal IC Tester is a static tester, which means this does not dynamically test the IC’s operation. All ICs with up to 20 pins can be tested by this unit. ICs with more than […]





