Ham Radio General Class Practice Test

What is the peak-inverse-voltage across the rectifiers in a full-wave bridge power supply?

1. One-quarter the normal output voltage of the power supply

2. Half the normal output voltage of the power supply

3. Double the normal peak output voltage of the power supply

4. Equal to the normal peak output voltage of the power supply

The correct answer is: Equal to the normal peak output voltage of the power supply

In a full-wave bridge power supply configuration, the peak-inverse-voltage (PIV) across the rectifiers is a critical parameter that refers to the maximum voltage that each diode in the bridge must withstand in the reverse direction when it is not conducting. During operation, two diodes conduct at any given time while the other two do not. The PIV is the peak voltage that can appear across each non-conducting diode when the output voltage of the power supply reaches its maximum peak. The output voltage in a full-wave bridge rectifier is equal to the peak voltage of the input AC signal. Therefore, when two diodes are conducting, the full AC voltage peak from the transformer is applied across the two diodes that are not conducting, creating the need for each diode to withstand a voltage equal to the peak output voltage. This means that the PIV rating must be not only equal to the maximum output voltage but should also comfortably cover this value depending on the design and reliability principles applied. Therefore, in a well-designed rectifier circuit, the peak-inverse voltage is indeed equal to the normal peak output voltage of the power supply, which justifies the selection of this response.