Input characteristics of a BJT in CB mode

[Pushoam]

Homework Statement

Does this mean that the forward bias p-n junction starts behaving as a conductor at very small input voltage i.e. of the order of 50 mV and it decreases as V_CB increases?
The two circuits i.e. forward bias circuit and reverse bias circuit are independent. Then why should $I_E$ depend upon $V_{CB}$?

Homework Equations

The Attempt at a Solution

 

[rude man]

Homework Statement

View attachment 211268

Does this mean that the forward bias p-n junction starts behaving as a conductor at very small input voltage i.e. of the order of 50 mV

Yes.

and it decreases as V_CB increases?

The opposite. Since emitter current increases with Vcb for a given emitter-base voltage, raising Vcb makes the e-b junction look more like a conductor, not less.

The two circuits i.e. forward bias circuit and reverse bias circuit are independent. Then why should $I_E$ depend upon $V_{CB}$?

What two circuits? It's the same circuit.

 

[Pushoam]

What two circuits?

The whole CB mode circuit was divided into the two circuits( I didn't specify it clearly. Sorry for it.).
The one circuit relates to the input circuit ( i.e forward bias p-n junction).
The another circuit relates to the output circuit (i.e. reverse bias p-n junction).

Thank you for helping me.

I wanted to know, why does $I_E$ depend on $V_{CB}$?

 

[rude man]

I wanted to know, why does $I_E$ depend on $V_{CB}$?

Good question. Google the Early Effect in bipolar junction transistors. Wikipedia has a very good explanation.