Hi. In most bjt operation explanations they say that initially the emitter base junction is forward biased ("turned on") but they don't mention anything about conductivity modulation. Whereby when the base collector junction becomes forward biased through Vbc>0 only then do they mention conductivity modulation.
Doesn't conductivity modulation occur in the base emitter junction as well??

 

Cerkit,

In most bjt operation explanations they say that initially the emitter base junction is forward biased ("turned on") but they don't mention anything about conductivity modulation.

You are right about that. I have never heard of that term before. Where did you come across it?

Whereby when the base collector junction becomes forward biased through Vbc>0 only then do they mention conductivity modulation.

What have you been reading? In the linear region, the base-collector junction is reversed biased.

Doesn't conductivity modulation occur in the base emitter junction as well??

I don't know, what does "conductivity modulation" it mean? Both junctions work in a unified manner.

Ratch

 

Conductivity modulation is when the conductivity of a region has been enhanced. This is when due an applied voltage there is an injection of holes into the n region of collector and due to this there is an influx of electrons to balance the space charge.