How to find emitter of unknown transistor without circuit board and power?

Question

Dear / Respected Electronic friends, I'm not electronician but have towards it. Every time I bring a new unknown transistor without using datasheet of it how can I identify its emitter or collector? Please help me!

Answer 1

If this is something that happens often, you could build a circuit to test your transistors. Designs are here:

http://www.talkingelectronics.com/html/Combo-2.html

You can buy the assembled circuit for $21.50, so I would think building it yourself would cost a little less than $21.50.

Answer 2

You can narrow it down by doing a diode test to find the base and the polarity or indeed if it is a bipolar transistor. Then do a gain test hFE on it. It should have a better gain the right way up.

Answer 3

locate the notch on the transitor start clock wise you will come across emitter collector and base