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GATE 2026 EE – Question 27

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

The figure shows a straight-line approximation for the forward characteristics of a power diode. A continuous on-state current of 15 A is flowing through the diode.

What is the power loss in the diode?

Diagram for GATE 2026 EE question 27
  1. 32.8 W
  2. 21.2 W
  3. 18.6 W
  4. 23.1 W

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Show answer and explanation

Correct answer: (C) 18.6 W

Explanation

From the plot the diode has a threshold voltage $V_0=1.0$ V at zero current and reaches 1.8 V at 50 A, so the slope (on-state resistance) is $r=\dfrac{1.8-1.0}{50}=0.016\ \Omega$. At 15 A the on-state voltage is $1.0+0.016\times15=1.24$ V. The loss is $1.24\times15=18.6$ W.