Question

What values of VBE and α would provide maximum stability?

(a) VBE = 5V, α = 50

(b) VBE = 4V, α = 100

(c) VBE = 4.5V, α = 50

(d) It is irrelevant

The question was posed to me in my homework.

My query is from The Alpha Cutoff Frequency topic in division High Frequency Transistor of Electronic Devices & Circuits

Answer 1

Correct choice is (d) It is irrelevant

For explanation: In a stable alpha cutoff frequency, the variations in the value of VBE and α do not affect the stability of the system. The current through the emitter remains unchanged. Hence, the values can vary without hampering the system.