The main characteristics of the diode is unidirectional conductivity, that is, under the action of the forward voltage, the on-resistance is very small; while the reverse voltage effect on-resistance is very large or infinity. Because of the diode has the above characteristics, the circuit often used in the rectifier circuit, then the role of Zener diode is what? Let's take a look.

Zener diode voltage regulator principle: Zener diode is the reverse voltage breakdown plus the breakdown, the voltage at both ends of the basic remain unchanged. The rectifier diode is damaged after the reverse breakdown. In this way, when the voltage regulator connected to the circuit, if the power supply voltage fluctuations, or other causes of the circuit voltage changes at each point, the voltage across the load will remain essentially unchanged. Zener diode used to regulate or in the series circuit as a reference voltage.

Rectifier diodes and Zener diodes are PN semiconductor devices, the difference is that the rectifier diode is used in the unidirectional conductivity Zener diode is the use of its reverse characteristics, the reverse connection in the circuit.

The main purpose of the regulator is to stabilize the voltage. In the request of accuracy is not high, the current range is not large, the regulator can be selected and the need for the most close to the regulator in parallel with the load directly. Regulated, steady current power supply system as a general reference power, but also in the integrated op amp as a DC level shift.

The above is the role of Zener diode, as the name suggests is a stable voltage.