Hi,

Quick question regarding modes of an NPN BJT.

If current is feeding through the base out through the emitter with zero collector current, is the transistor considered to be in the cutoff region?

Ic = 0
Ib = 1mA
Ie = 1mA

Thanks!

 

What does the textbook say?

 

That's kind of like, "If the car is rolling downhill, and the transmission is in first gear, but the engine is not running, what mode is that called?" I don't think that is a "mode". Certainly the transmission thinks it is capable of transferring power, but it doesn't have any to transfer. If I had to guess, I'd say it's not in cutoff, but neither is it in the linear region. More like, "What mode is a transistor in if I didn't connect it correctly for any mode?"

 

if the base to emtter is drawing current, the transistor should be conducting. is there anything connected to the collector preferably positive.

 

if the base to emtter is drawing current, the transistor should be conducting. is there anything connected to the collector preferably positive.

Collector is not connected to anything, hence Ic=0.

 

Starvation mode. I've heard it called.

Not enough collector voltage.

 

You have a diode in that mode...

 

I agree with tindel. The transistor base-emitter junction is acting as a two-terminal diode. The collector has no effect since it is open.