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Vₘ is the maximum voltage between the ends of the secondary terminal of a transformer used in a half wave rectifier. When the PN junction diode is reverse biased, what will be the potential difference between two ends of the diode?

Asked in GSEB Board July 2017; GSEB Board March 2019 · Output waveforms

Answer: (3) Vₘ

Step-by-step solution

Idea: in a half wave rectifier the diode and the load resistor sit in series across the secondary winding, so at every instant the secondary voltage is shared between just those two.

On the half cycle that reverse biases the diode, the diode blocks and no current flows round the loop.

With no current there is no drop across the load resistor, so the whole of the secondary voltage appears across the diode.

At the peak of that half cycle the secondary voltage is Vₘ, so the diode has to stand off Vₘ -- this is what is meant by its peak inverse voltage.

So the potential difference between the two ends of the reverse biased diode is Vₘ.

Why the other options are wrong

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