Simple Continuity Tester Circuit Diagram Diy

Simple 1 transistor based Continuity Tester Circuit Diagram

First published in my old blog at

This circuit is a countinuity tester, it can be used to test continuity of a wire or any kinds of conductors.

Continuity Tester Circuit Diagram

Working of the circuit is simple, the T1 transistor will not get power and current in it’s base pin if a wire which you test is broken so you can assume that the wire you test has a cut somewhere inside it. But when you test a good wire, the T1 will get current in its base pin so it turns on and the buzzer sounds.

This circuit can also be used in the paths of a PCB to know whether it’s ok or not.

having any questions? Leave a comment below!

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