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Old 20th Jun 2009, 3:43 pm   #2
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Default Re: Testing Transistors.

Moving on to transistors the device being tested here is an NPN silicon device. As with most, but not all, transistors the base lead is in the centre with the emitter and collector leads on either side.

The test procedure is to connect the black lead to the base and the red lead to the collector and emitter in turn. Then repeat with the red lead connected to the base and the black lead connected to the collector and emitter in turn. Note that in one direction we see a forward volt drop and in the other an infinite resistance.

As long as you can identify the base lead it doesn't really matter which is collector and emitter, so long as you see volt drop one way and infinite resistance the other.
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