Question

The base current for a BJT remains constant at 5mA, the collector current changes from 0.2mA to 0.3 mA and beta was changed from 100 to 110, then calculate the value of S.

(a) 0.01m

(b) 1m

(c) 100m

(d) 25m

I got this question in unit test.

My query is from Bias Stability topic in portion Transistor Biasing and Thermal Stabilization of Electronic Devices & Circuits

Answer 1

Correct option is (a) 0.01m

To explain: Since the current in the above case, remains constant, therefore stability factor is 0.01 as it is defined as the ratio of change in collector current to change in beta.

S=change in collector current/change in beta=0.1mA/10=0.01m.