A very simple transistor tester electronic circuit project can be designed using this circuit diagram . This transistor tester electronic circuit project is very useful for testing both types of transistors pnp and npn. This transistor tester electronic circuit project is composed from few common electronic parts like : resistors, LEDs and diodes . The circuit is powered from a simple 6 volts unregulated power supply ( you can use a small 6 volts step down transformer) . The tested transistor must be inserted in the EBC terminals of the device ( emitter, base, collector) . Each pin of the transistor must be connected to its correspondent ( emitter to emitter, base to base and collector to collector) .
The resistor that will be connected in series with base pin of transistor is selected using a simple six position rotary switch S1 as per base current requirement for the under test transistor.
When the green transistor glows it means that the npn transistor under test is in a good condition. If a good pnp transistor is tested , the red LED must be glowing .
All components must be mounted on a small printed circuit board .