Question

What is the approximate hybrid parameter voltage gain of a CC amplifier?

(a) 1 + hie × Ri

(b) 1 – hie × Ri

(c) 1 + hie / Ri

(d) 1 – hie / Ri

I had been asked this question in my homework.

This intriguing question originated from Approximate Hybrid Model and its use in CE, CB, CC in section Small-Signal Low-Frequency AC models of Transistors of Electronic Devices & Circuits

Answer 1

The correct choice is (d) 1 – hie / Ri

To explain: The voltage gain of a 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.