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 […]
Meters and Testers
2 Simple Milliohm Meter Circuits [Measure Low Resistances below 1 Ohm with these Circuits]
The low resistance measuring circuit I have explained below can be used for measuring all milliohm resistances below 1 ohm with extreme accuracy. The resistance to be measured can be as low as 0.01 ohm or 10 milliohm. The output of the circuit converts the resistance value to exactly equivalent volts, which means the output […]
3-Digit LED Capacitance Meter Circuit
This project is yet another test equipment that can be extremely handy to any electronic hobbyist, and building this unit can be a lot of fun. A capacitance meter is a very useful test equipment as it allows the user to check a desired capacitor and confirm its relaibility. Ordinary or standard digital meters mostly […]
Match Transistor Pairs Quickly using this Circuit
In many critical circuit applications, like power amplifiers, inverters, etc it becomes necessary to use matched transistor pairs having identical hFE gain. Not doing this possibly creates unpredictable output results, such as one transistor getting hotter than the other, or asymmetrical output conditions. By: David Corbill To eliminate this, matching transistor pairs with their Vbe […]
5 Digit Frequency Counter Circuit
This digital frequency counter will provide a direct reading of the frequency applied at its input, through a 5 digit common cathode display module. The compact frequency counter can be used for accurately counting the frequency or pulse from any intended source. Main Applications It can be also used for measuring the RPM of a […]
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 […]