In a half-wave power supply with a capacitor input filter and a load drawing little or no current, the peak inverse voltage (PIV) across the diode can reach _____ times the RMS voltage.

In a half-wave rectifier with a capacitor input filter, the capacitor charges to the peak value of the AC wave, which is about 1.414 times the RMS voltage. Because there is little to no load current to drain this charge, the capacitor holds this positive peak voltage steadily on the diode's cathode. When the AC cycle reverses, the transformer secondary swings to the negative peak (also 1.414 times the RMS voltage) on the diode's anode. The total potential difference across the non-conducting diode is the sum of these two peaks: 1.414 + 1.414 = 2.828. Therefore, the Peak Inverse Voltage (PIV) reaches approximately 2.8 times the RMS voltage.