Question

Given hfe = 60, hie=1000Ω, hoe = 20μ Ω^–, hre = 2 * 10^-4. Find the current gain of the BJT, correct up to two decimal points.

(a) – 58.44

(b) -59.21

(c) – 60.10

(d) – 60.00

This question was posed to me in a job interview.

I need to ask this question from Hybrid Equivalent Model in section Transistor Biasing and Low Frequencies of Analog Circuits

Answer 1

Correct option is (a) – 58.44

To elaborate: Current gain, AI = – hf/(1 + hoRL’) where RL’ = 2kΩ||4kΩ

RL’ = 1.33kΩ.

Thus AI = – 60/(1 + 0.0266) = -58.4453.