Question

For the 2 port network as shown below, the Z-matrix is ___________

(a) [Z1; Z1 + Z2; Z1 + Z2; Z3]

(b) [Z1; Z1; Z1 + Z2; Z2]

(c) [Z1; Z2; Z2; Z1 + Z2]

(d) [Z1; Z1; Z1; Z1 + Z2]

I got this question at a job interview.

My doubt stems from Inverse Hybrid (g) Parameter topic in section Two-Port Networks of Network Theory

Answer 1

The correct option is (d) [Z1; Z1; Z1; Z1 + Z2]

To explain I would say: z11 = \(\frac{V_1}{I_1}\), when I2 = 0

z22 = \(\frac{V_2}{I_2}\), when I1 = 0

z12 = \(\frac{V_1}{I_2}\), when I1 = 0

z21 = \(\frac{V_2}{I_1}\), when I2 = 0

Now, in the given circuit putting I1 = 0, we get,

z12 = Z1 and z22 = Z1 + Z2

And putting I2 = 0, we get,

z21 = Z1 and z11 = Z1.