Concept:In a half-wave voltage doubler, one diode clamps the AC wave to a \( V_m \) DC level while the second diode rectifies the shifted wave, subjecting both diodes to a maximum reverse voltage of \( 2V_m \).
Formula:$$\text{PIV}_{\text{doubler diodes}} = 2 V_m$$
Solution:- The clamping capacitor charges to \( V_m \).
- During the alternate peak, the combined transformer and capacitor voltage applies \( 2V_m \) in reverse across the non-conducting diode.
- Therefore, all diodes in a standard half-wave voltage doubler must be rated for \( \text{PIV} = 2V_m \).
Why other options are incorrect:- Option B: \( V_m \) is insufficient and would cause reverse breakdown.
- Option C: \( 4V_m \) is the total DC output of a voltage quadrupler, not the PIV per diode.
- Option D: \( V_m / 2 \) is far below the required PIV rating.
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