Question

For a 2-port network, the value of the h parameter is as h=[600, 0.04; 30, 2×10^-3]. Given that, ZS = 2 kΩ and ZL = 400 Ω. The value of the parameter Zin is ______________

(a) 250 Ω

(b) 333.33 Ω

(c) 650 Ω

(d) 600 Ω

The question was asked during a job interview.

My enquiry is from Advanced Problems Involving Parameters in portion Two-Port Networks of Network Theory

Answer 1

The correct choice is (b) 333.33 Ω

To explain I would say: Zin = hie – \(\frac{h_{re} h_{fe} R_L}{1 + h_{oe} R_L}\)

= h11 – \(\frac{h_{12} h_{21} R_L}{1+h_{22} R_L}\)

= 600 – \(\frac{0.04×30×400}{1+2×10^{-3}×400}\) = 333.33 Ω.