Question

Find the driving point impedance Z11 (S) in the circuit shown below.

(a) 2(s+2)

(b) (s+2)

(c) 2(s+1)

(d) (s+1)

I have been asked this question during an internship interview.

The doubt is from Network Function for the One-Port and Two-Port in portion S-Domain Analysis of Network Theory

Answer 1

Correct option is (c) 2(s+1)

Best explanation: The driving point impedance Z11 (S) is Z11 (S)=V1(S)/I1(S). V1 (S) = 2 I1 (S) + 2 sI1 (S) => V1(S) = (2+2s)I1(S) => V1(S)/I1(S) = 2(s+1). On substituting Z11 (S) = 2(S+1).