Question

For the circuit given below, the value of the hybrid parameter h11 is ___________

(a) 75 Ω

(b) 80 Ω

(c) 90 Ω

(d) 105 Ω

This question was addressed to me during an online exam.

Question is taken from Advanced Problems on Two Port Network in section Two-Port Networks of Network Theory

Answer 1

Right choice is (a) 75 Ω

The best I can explain: Hybrid parameter h11 is given by, h11 = \(\frac{V_1}{I_1}\), when V2=0.

Therefore short circuiting the terminal Y-Y’, we get,

 V1 = I1 ((50||50) + 50)

= I1 \(\left(\left(\frac{50×50}{50+50}\right) + 50\right)\)

= 75I1

∴ \(\frac{V_1}{I_1}\) = 75.

Hence h11 = 75 Ω.