Peak inverse voltage (PIV) is the largest reverse voltage a Diode is subjected to during normal operation of a rectifier circuit. It is a worst-case figure: the diode’s reverse-voltage rating must exceed the PIV, or the diode will be driven into Reverse breakdown every cycle and destroyed.
Why it matters
A rectifier diode spends part of every cycle reverse biased (Reverse bias) while the rest of the circuit drives a voltage across it. If that voltage ever exceeds the diode’s breakdown rating, the diode conducts in reverse and overheats. So sizing a rectifier is not only about forward current — you must also find the maximum reverse voltage any diode sees and pick a part rated comfortably above it. PIV is that maximum.
PIV for each rectifier topology
The value depends entirely on circuit topology, because what sets the reverse voltage is where the diode’s two terminals are pinned when it is off.
- Half-wave rectifier: PIV . When the input is at its blocked-polarity peak, the diode is off so no current flows, the load has 0 V across it, and the entire input peak appears across the diode.
- Center-tapped full-wave rectifier: PIV . The off diode has its cathode tied (through the load) to about from the conducting diode, while its anode is at the opposite winding end at . The reverse voltage is — the major drawback of this topology.
- Bridge rectifier: PIV . The off diodes are protected by the conducting pair, so no diode ever sees more than one peak. This is about half the centre-tapped value and is one of the bridge’s main advantages.
The practical takeaway: a bridge lets you use lower-voltage (cheaper, faster) diodes than a centre-tapped design for the same input peak, while the centre-tapped design forces a -rated part. Always derate generously — line transients can push the instantaneous reverse voltage well above the nominal .