Ham Radio General Class Practice Test

What is the peak-inverse-voltage across the rectifier in a half-wave power supply?

1. One-half the normal peak output voltage of the power supply

2. One-half the normal output voltage of the power supply

3. Equal to the normal output voltage of the power supply

4. Two times the normal peak output voltage of the power supply

The correct answer is: Two times the normal peak output voltage of the power supply

In a half-wave rectifier circuit, the peak-inverse-voltage (PIV) is a critical parameter that indicates the maximum voltage that the rectifier diode must withstand in the reverse direction without breaking down. During the negative cycle of the AC input, the diode becomes reverse-biased and the full peak voltage of the AC signal appears across it. Thus, the PIV is equal to the peak output voltage of the transformer secondary winding, which is typically twice the normal output voltage during rectification due to the sine wave characteristics of the AC supply. When the diode conducts during the positive half-cycle, it allows current to pass, but during the negative half-cycle, the diode blocks current flow, and the peak voltage is applied in reverse, leading to the need for the diode to withstand this potential without failure. Understanding this concept is essential for designing rectifier circuits, ensuring that the components can handle the expected voltages safely. This solidifies why the peak-inverse-voltage across the rectifier in a half-wave power supply is indeed two times the normal peak output voltage of the power supply.