Question

In the circuit given below, the value of the hybrid parameter h21 is _________

(a) 10 Ω

(b) 0.5 Ω

(c) 5 Ω

(d) 2.5 Ω

I got this question in exam.

Enquiry is from Hybrid (h) Parameter in section Two-Port Networks of Network Theory

Answer 1

Correct choice is (b) 0.5 Ω

Explanation: Hybrid parameter h21 is given by, h21 = \(\frac{I_2}{I_1}\), when V2 = 0.

Therefore short circuiting the terminal Y-Y’, and applying Kirchhoff’s law, we get,

-5 I2 – (I2 – I1)5 = 0

Or, -I2 = I2 – I1

Or, -2I2 = -I1

∴  \(\frac{I_2}{I_1} = \frac{1}{2}\)

 Hence h21 = 0.5 Ω.