Question

Two networks are connected in series parallel connection. Then, the forward short-circuit current gain of the network is ____________

(a) Product of Z-parameter matrices

(b) Sum of h-parameter matrices

(c) Sum of Z-parameter matrices

(d) Product of h-parameter matrices

The question was posed to me in unit test.

This question is from Series-Series Connection of Two Port Network topic in section Two-Port Networks of Network Theory

Answer 1

Right choice is (b) Sum of h-parameter matrices

For explanation: The forward short circuit current gain is given by,

h21 =  \(\frac{I_2 (s)}{I_1 (s)}\), when V2 = 0

So, when the two networks are connected in series parallel combination,

[h11, h12; h21, h22] = [h’11 + h’11, h’12 + h’12; h’21 + h’21, h’22 + h’22]

So, h21 of total network will be sum of h parameter matrices.