Question

How is the h21 hybrid-pi conductance in low frequency H-parameters of a two-port network used?

(a) It is used as a voltage source at input port

(b) It is used as a current source at input port

(c) It is used as a voltage source at output port

(d) It is used as a current source at output port

The question was asked during an interview.

I would like to ask this question from Hybrid PI Conductances in Low Frequency H Parameters topic in section High Frequency Transistor of Electronic Devices & Circuits

Answer 1

Right choice is (d) It is used as a current source at output port

To elaborate: While checking the hybrid-pi conductance in low frequency H-parameters equivalent network of a two-port network we see that the hybrid-pi conductance in low frequency H-parameters h21 is sued as a current source at the output port. While using Kirchhoff’s current law, the hybrid-pi conductance in low frequency H-parameters equations can be represented as a current source of h21 I1 .