Explanation:
Peak inverse voltage (PIV) is the maximum voltage that a diode can withstand in the reverse bias direction without getting damaged. The PIV rating of a diode is an important consideration in rectifier circuits.

Full Wave Rectifier:
In a full wave rectifier, both halves of the AC input waveform are rectified, resulting in a DC output voltage. The PIV rating of a full wave rectifier is dependent on the secondary voltage of the transformer and the number of turns in the secondary winding.

Reasons why PIV is highest in a full wave rectifier:

- During one half of the AC cycle, the diodes conduct in the forward bias direction, allowing current to flow through the load. During the other half of the cycle, the diodes are in reverse bias, and no current flows through the load.
- In a full wave rectifier, the diodes are arranged in a bridge configuration, which means that the voltage across each diode is equal to the peak secondary voltage of the transformer. This is because each diode is connected to both ends of the secondary winding.
- Since the voltage across each diode is equal to the peak secondary voltage, the PIV rating of each diode is also equal to the peak secondary voltage. Therefore, the PIV rating of a full wave rectifier is twice the peak secondary voltage.

Conclusion:
In conclusion, the PIV rating is highest in a full wave rectifier because of the bridge configuration and the fact that each diode is subjected to the peak secondary voltage. Therefore, a full wave rectifier is the best choice for applications where high PIV ratings are required.

PIV for an half wave and bridge wave rectifier is Vm ( maximum or peak voltage). for three phase full wave rectifier is √3 x Vm. for full wave rectifier PIV= 2xVm.