Question

For a T-network if the Open circuit impedance parameters are given as z11, z21, z12, z22, then z22 in terms of Hybrid parameters can be expressed as ________ (a) z22 = \left(h_{11} – \frac{h_{21} h_{12}}{h_{22}}\right) (b) z22 = – \frac{h_{21}}{h_{22}} (c) z22 = \frac{h_{12}}{h_{22}} (d) z22 = \frac{1}{h_{22}} This question was posed to me in final exam. My query is from Relation between Hybrid Parameters with Short Circuit Admittance and Open Circuit Impedance Parameters topic in chapter Two-Port Networks of Network Theory Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

Answer 1

Right choice is (d) z22 = \frac{1}{h_{22}} The best explanation: We know that, V1 = z11 I1 + z12 I2 ……… (1) V2 = z21 I1 + z22 I2 ………. (2) And, V1 = h11 I1 + h12 V2 ………. (3) I2 = h21 I1 + h22 V2 ……….. (4) Now, (3) and (4) can be rewritten as, V1 = \left(h_{11} – \frac{h_{21} h_{12}}{h_{22}}\right) \frac{I_1 + h_{12}}{h_{22}}I_2 ………… (5) And V2 = \frac{I_2}{h_{22}} – \frac{h_{21} I_1}{h_{22}} ……….. (6) ∴ Comparing (1), (2) and (5), (6), we get, z11 = \left(h_{11} – \frac{h_{21} h_{12}}{h_{22}}\right) z12 = \frac{h_{12}}{h_{22}} z21 = – \frac{h_{21}}{h_{22}} z22 = \frac{1}{h_{22}} .