Question

with proper diagrams, explain the movement of charge carriers through different parts of the transistor and hence show that Ie=Ib+Ic

Answer 1

Given Diagram illustrates the movement of electrons in pnp Transistors.

1. The forward bias of emitter base circuits repels the holes of emitter towards the base and electrons of the base towards emitter.

2. As very thin base is chosen with light doping.

3.Most or the holes  entering the base pass on to collector and while few recombine with electrons in base region.


4.As soon as holes combines with the electrons, an electrons from the negative terminal of baterry VEb enters the base.

5. This will set up small base current Ib.

6. Each hole entering the collector region again combines with electron from the negative terminal of battery Vcb and gets neutralized.

7. This will set up collector current Ic.

8. In both the case Ib and Ic combine to forms emitter current Ie.

Hence Ie=Ib+Ic