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GATE 2015 EC – Question 21

Analog Circuits · Diode Circuits · 1 mark · Multiple choice

For the circuit with ideal diodes shown in the figure, the shape of the output ($v_{out}$) for the given sine wave input ($v_{in}$) will be

Two ideal diodes are connected to the input in a crossed arrangement, feeding a load resistor from which $v_{out}$ is taken. The input is a sine wave over one period $T$. Four candidate output waveforms (A) to (D) are given.
  1. Waveform (A): the full input sine wave
  2. Waveform (B): the inverted input
  3. Waveform (C): only the negative half-cycle
  4. Waveform (D): only the positive half-cycle

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Show answer and explanation

Correct answer: (C) Waveform (C): only the negative half-cycle

Explanation

With the diodes oriented as shown, only one diode can conduct at a time, and the load sees only the negative half-cycle of the input. So the output is the waveform that keeps the negative half and is zero for the positive half, which is option C according to the official key.