- on Test & Measurement
- Published in issue 12/2003 on page 0
Cheap and Cheerful Transistor Tester
By using a simple visual indicating system, this small transistor tester allows you to run a quick ‘go/non-go’ check on NPN as well as PNP transistors. If the device under test is a working NPN then the green LED (D1) will flash, while the red counterpart will flash for a functional PNP device. However if the transistor is shorted, both LEDs will flash, and an open-circuit device will cause the LEDs to remain off.