Question

How do we compute the voltage gain of a simplified CC amplifier model using hybrid parameters?

(a) 1 + hie × Ri

(b) 1 – hie × Ri

(c) 1 + hie / Ri

(d) 1 – hie / Ri

This question was posed to me during an interview.

My doubt stems from Simplified Calculations for the CC Configuration in division Low Frequency Transistor Amplifier Circuit of Electronic Devices & Circuits

Answer 1

Right answer is (d) 1 – hie / Ri

For explanation I would say: The voltage gain of as implified common collector (CC) amplifier can be expressed in terms of approximate hybrid parameters. The voltage gain is equal to 1 – hie / Ri  where, Ri  is equal to hie + (1 + hfe) × RL .