Question

Why do we require RE for a good stable bias circuit?

(a) To obtain a current IE sensitive to β and VBE

(b) To obtain a current IB sensitive to β and VBE

(c) To obtain a current IE insensitive to β and VBE

(d) To obtain a current IB insensitive to β and VBE

This question was addressed to me in quiz.

The query is from Stabilization against Variations in VBE and Beta for Self Bias Circuit in chapter Transistor Biasing and Thermal Stabilization of Electronic Devices & Circuits

Answer 1

The correct answer is (c) To obtain a current IE insensitive to β and VBE

The explanation is: The aim of having a bias circuit is to maintain a stable current or voltage, regardless of other parameters changing. Hence, we need RE to get a stable IE current, without RE the value of IE changes drastically with a small change in β.