Peak Inverse Voltage (Centre-Tap)

Formula

Description

Peak inverse voltage is the maximum reverse voltage a rectifier diode must withstand when not conducting. In a centre-tapped full-wave rectifier the non-conducting diode sees the full secondary swing plus the peak across the conducting half, totalling twice the peak voltage. Diodes must be rated above the PIV with margin, or they break down on the reverse half-cycle.

Variables

• PIV — Peak inverse (reverse) voltage on the diode (V)
• Vpeak — Peak of one half of the secondary (V)

Practical Notes

For a bridge rectifier the PIV is only Vpeak (one diode drop less), which is why bridges allow lower-voltage diodes than centre-tap designs. Always derate: choose diodes rated well above the calculated PIV.