Hello guys,

I was trying to figure out if a NPN transistor is leaky or not so I had my DMM turned to diode mode and did the following:

+lead at base & -lead at collector: 0.6V (good)
+lead at base & -lead at emitter: 0.6V (good)

-lead at base & +lead at collector: OL (good)
-lead at base & +lead at emitter: 2V (?)

-lead at collector & +lead at emitter: OL (good)
+lead at collector & -lead at emitter: OL (good)

My question is that am I supposed to at a 2V drop across BE when it's reversed biased? Shouldn't it be OL as well?

 

That is what I would expect to see for a typical small signal transistor. Some Darlington transistors will have resistance between the base and emitter. What is the part number of the transistor you are testing?

 

That is what I would expect to see for a typical small signal transistor. Some Darlington transistors will have resistance between the base and emitter. What is the part number of the transistor you are testing?

I've seen the internal pull down on at least one non-Darlington as well - IIRC the part was described as an NPN BJT in some spots, and as an open collector inverter in other spots.

 

Hello,

What is the partnumber of the BJT?

Bertus