Define stability factors of a transistor operated at Q-Point?


The main aim of biasing circuits is to stabilise the transistor’s operating point irrespective of variations in Ico, β, Vbe which vary because of varying temperature. Mainly the variation of Ico with temperature is a significant one and has to be taken care of. Accordingly a stability factor is defined o quantify the stability of biasing circuits with respect to variation in transistor parameters.

Stability Factor S = Ic/ Ico

Similarly S’ = Ic/ β, S’’= Ic/ Vbe