Question

For a T-network if the Short circuit admittance parameters are given as y11, y21, y12, y22, then y21 in terms of Inverse Hybrid parameters can be expressed as ________ (a) y21 = \left(g_{11} – \frac{g_{12} g_{21}}{g_{22}}\right) (b) y21 = \frac{g_{12}}{g_{22}} (c) y21 = –\frac{g_{21}}{g_{22}} (d) y21 = \frac{1}{g_{22}} I have been asked this question in an interview. My doubt stems from Inverse Hybrid (g) Parameter in portion 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

The correct choice is (c) y21 = –\frac{g_{21}}{g_{22}} The explanation is: We know that, I1 = y11 V1 + y12 V2 ……… (1) I2 = y21 V1 + y22 V2 ………. (2) And, I1 = g11 V1 + g12 I2 ………. (3) V2 = g21 V1 + g22 I2 ……….. (4) Now, (3) and (4) can be rewritten as, I1 = \left(g_{11} – \frac{g_{12} g_{21}}{g_{22}}\right)V_1 + \frac{g_{12}}{g_{22}} V_2 ………. (5) And I2 = –\frac{g_{21} V_1}{g_{22}} + \frac{V_2}{g_{22}} ………. (6) ∴ Comparing (1), (2) and (5), (6), we get, y11 = \left(g_{11} – \frac{g_{12} g_{21}}{g_{22}}\right) y12 = \frac{g_{12}}{g_{22}} y21 = –\frac{g_{21}}{g_{22}} y22 = \frac{1}{g_{22}} .