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NPN transistor

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New Member
I have a working transistor but the label is missing. How do I find out what it is? I think it is a NPN. It is a power transistor in a T0-3 package. Is there anyway to figure out what it is?
Thanks in advance


New Member
my guess would be that it would be pretty hard to find out what kind of transistor it is. Though you could find out where E,B, and C are, but that still wouldn't help you out.


Active Member
In TO-3 package the case is collector. You can find out the structure with diode-checker or multimeter: connect +wire to pin1 -wire to other pin,afterward -wire to case.If You find with this method two conducted diodes,it`s NPN transistor,and +wire the base.If nothing found, change polarity..... nothing found connect the + to another pin....
I hope You can understand my bad english,unfortunately i never learn.Maybe help for You.
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