LIZ zener diode is a semiconductor device that has a very high resistance until the critical reverse breakdown voltage. At this critical breakdown point, the reverse resistance decreases to a very small value in this low resistance region The current increases and the voltage remains constant. The zener diode is divided according to the breakdown voltage. Because of this characteristic, the zener tube is mainly used as a voltage regulator or voltage reference element. Zener diodes can be connected in series for use at higher voltages, and higher stable voltages can be obtained by connecting in series.