Page 137 - Testing Electronic Components

Since you have confirmed that pin 2 is the Base, we now move to the
other steps to find the Collector and the Emitter. Set to X 10 K Ohms and
place any of your test probes to pin 1 and 3. Assuming the black probe to
pin 3 and the red probe to pin 1 and you don’t get any reading then pin 1
is the Collector. If you reverse the test probes, you will definitely see the
pointer kick up. In other words we must look for the measurement that
don’t get any reading and see the red probe connects to which pin. If the
red probe connects to pin 2 then pin 2 is the Collector. If it connects to
pin 1 then pin 1 is the Collector.

In the above case, since pin 1 is the Collector then pin 3 must be Emitter.
Although semiconductor data book do show which pin is the base,

collector and emitter, we can’t fully depend on it as I found it not 100%
accurate. The best you test and find it on your own.

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