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GATE 2023 EC – Question 54

Electromagnetics · Transmission Lines · 2 marks · Multiple select

The following circuit(s) representing a lumped element equivalent of an infinitesimal section of a transmission line is/are

Diagram for GATE 2023 EC question 54
  1. Circuit (A)
  2. Circuit (B)
  3. Circuit (C)
  4. Circuit (D)

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Show answer and explanation

Correct answer: (B) Circuit (B); (C) Circuit (C); (D) Circuit (D)

Explanation

A transmission-line section of length $\Delta z$ has series $R\Delta z,\ L\Delta z$ and shunt $G\Delta z,\ C\Delta z$. The L-section in (B), the symmetric $\pi$-section in (C) (shunt elements split equally at both ends) and the symmetric T-section in (D) (series elements split equally on both sides) all contain exactly these totals in valid topologies. In (A) the shunt capacitance and conductance are placed at opposite ends of the series branch, which is not a standard equivalent section.