A full-wave rectiﬁer circuit is driven by a sinusoidal input voltage with Vrms=15V and frequency 50Hz. If the load resistance is 100Ω, with a ﬁlter capacitance of 1.5mF? (Assume the diodes to be ideal, with Von=0V.)

Question

A full-wave rectiﬁer circuit is driven by a sinusoidal input voltage with Vrms=15V and frequency 50Hz. If the load resistance is 100Ω, with a ﬁlter capacitance of 1.5mF? (Assume the diodes to be ideal, with Von=0V.) 
what is the maximum instantaneous reverse voltage (approximately) across each diode?

Henry · Answer

Assuming a center-tapped transformer is used for the secondary winding,

Vp = Vrms * sqrt(2) = (15/2) * 1.414 = 10.61 Volts = Peak inverse voltage of each diode.

Note: Each diode sees 1/2 of the 15-volt rms supply.

Henry · Answer

Correction: The output voltage should be added to Vp. The max. possible voltage across the capacitor is 10.61 volts. Therefore, Vpmax = 2*(-10.61) = -21.2 Volts.