When the inverse voltage exceeds a certain value, the reverse current will suddenly increase, this phenomenon is called electrical breakdown. The critical voltage that causes the electric shock to wear is called the diode reverse breakdown voltage. The diode loses unidirectional conductivity when the electric shock wears. If the diode does not cause overheating due to electrical breakdown, the unidirectional conductivity may not be permanently destroyed, after the removal of the external voltage, its performance can be recovered, or the diode is damaged. Therefore, the diode should be used to avoid excessive reverse voltage.
Diode is a one-way conductive two-end devices, there are electronic diodes and crystal diode points, electronic diodes are rarely seen, more common and commonly used is crystal diode. The unidirectional conductivity of diodes is used in almost all electronic circuits, semiconductor diodes, which play an important role in many circuits, it is one of the earliest semiconductor devices, and its application is very widespread.