In the case of diodes, the operating range is referred to as the forward range and the range in which no current flows is referred to as the reverse range. The reverse range is the range in which the diode is operated with the opposite supply voltage.doping, the reverse voltage, which is relevant for regular operation, can be between a few volts and several kilovolts.
If the reverse voltage is increased beyond the reverse voltage range, this leads to breakdown due to the increasing electric field strength, which results in an abruptly increasing current. The voltage governing the breakdown is the breakdown voltage, which causes irreversible damage to normal diodes. The effect of breakdown is the avalanche effect, which is used in Zener diodes.