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GATE 2014 EE (EE1) – Question 35

Power Electronics · Static V-I characteristics and firing/gating circuits for Thyristor, MOSFET, IGBT · 1 mark · Multiple choice

Four switches (i)–(iv) are shown. Which block either polarity of voltage between a,b with their active device OFF?

Diagram for GATE 2014 EE (EE1) question 35
  1. (i), (ii) and (iii)
  2. (ii), (iii) and (iv)
  3. (ii) and (iii)
  4. (i) and (iv)

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Show answer and explanation

Correct answer: (C) (ii) and (iii)

Explanation

An antiparallel diode in(i)or(iv)conducts for one polarity even when the active device is off, so those combinations cannot block both signs. The series diode in(ii)blocks reverse voltage while the transistor blocks forward voltage, and the thyristor in(iii)blocks both polarities within its ratings. Thus **(ii)and(iii),C**.