The voltage stabilization process of a voltage regulator diode

The voltage stabilization process of a voltage regulator diode

If the reverse voltage of the zener diode is applied to a certain high level, the zener diode will pass through a large current due to breakdown. However, this phenomenon is exactly what we hope because this type of zener diode works in this breakdown state. As long as the voltage regulator works properly, it will always be in this state of breakdown. At this time, the current passing through it is high, but the voltage drop of the diode changes very little. Therefore, it can play a stabilizing role, and we also call it a Zener diode. It has the characteristics of normal diode forward conduction and reverse cutoff, but when the reverse voltage of this type of diode exceeds a certain value, it will experience breakdown, and this breakdown is soft breakdown and will not cause damage to the diode. The stabilizing effect of a voltage regulator diode is to utilize its reverse breakdown effect. The internal structure of the voltage regulator diode is also made of PN structure. When the PN junction undergoes reverse breakdown and the current changes within a certain range, the voltage will remain basically unchanged.

From the volt ampere characteristic curve of the voltage regulator diode, it can be seen that its forward characteristic is consistent with that of a regular diode, while its reverse characteristic is similar to that of a regular diode when it is below its breakdown voltage. It is at the cut-off point, but when the breakdown voltage is exceeded, the current changes rapidly, but the voltage remains within a very small range. The basic diode voltage stabilizing circuit maintains stable working voltage by reverse parallel connection with the load.