Question

The most stable biasing technique used is the ____________

(a) voltage-divider bias.

(b) base bias

(c) emitter bias

(d) collector bias

The question was posed to me by my college professor while I was bunking the class.

The question is from Input Bias and Offset Currents of the Bipolar Differential Amplifier in chapter Differential and Multistage Amplifiers of Electronic Devices & Circuits

Answer 1

The correct answer is (a) voltage-divider bias.

The best I can explain: Voltage divider biasing is commonly used because of the main reason that the transistor under this biasing always remains in the active region.

In voltage divider biasing, the voltages at the transistor’s base, emitter and collector all depend upon the external circuit i.e. the biasing resistors R1 and R2 whose valued are fixed thus variation with beta is not present here.

 However, voltage divider biasing has the advantage that its stability factor is greater than that of collector feedback biasing, that’s why it is used.