Question

On which of the following does base current not depend on?

(a) The thickness of the base

(b) The shape of the transistor

(c) Doping levels

(d) Number of charge carriers

I got this question during an interview.

My enquiry is from Semiconductor Electronics topic in chapter Semiconductor Electronics : Materials, Devices and Simple Circuits of Physics – Class 12

Answer 1

Right option is (d) Number of charge carriers

The best explanation: In an n-p-n transistor, as the base is very thin and lightly doped, a very few electrons from the emitter combine with the holes of the base, giving rise to base current and the electrons finally collected by the positive terminal of the battery gives rise to collector current. This base current is a small fraction of collector current depending on the shape of a transistor, thickness of the base, doping levels, and bias voltage.