Zener diode tutorial


What is Zener diode?

A zener diode or Breakdown diode is a PN diode specially designed for operation in the breakdown region in the reverse bias condition. This diode operates in zener breakdown or avalanche breakdown, However the word zener is used for all components having sharp breakdown characteristics in reverse direction.

Physical Construction of Zener diode:

zener diode construction

In zener diode heavily doped P and N semiconductors are used, this doping intensity increased by adding impurity to the semiconductor.

Symbol & Equivalent Circuit:

symbol equivalent zener

Here Vz represents zener voltage and Rz represents the slope of the nominally vertical region of the characteristic during breakdown at reverse bias.

Zener diode V-I characteristics:

zener bias

When we are connecting zener diode in forward bias that is +ve to anode and –ve to cathode terminal, zener diode will react as normal PN diode the characteristic shows that.

zener vi characteristics

When we apply reverse bias that is +ve to cathode and –ve to anode terminal, at particular reverse voltage breakdown occurs and gives constant zener voltage increase in current.

Zener diode applications:

With zener breakdown characteristics or avalanche breakdown characteristics, the zener diode used in many circuits.

Zener voltage regulator circuit

zener regulator

The zener diode connected shunt to the load and reverse in polarity to the power supply, different range of zener diode available in market, you need to choose right one for your circuit. (example : 2.2V ZD, 3V3 ZD, 6V ZD, 12V ZD etc..,)

Zener diode meter protection circuit

zener meter protection

When we use analog DC voltmeter, we pay more attention to the measuring voltage if the voltage rises beyond the limit of meter voltage range then the moving coil in the meter will got damage, to avoid we can place zener diode across the meter. (Note: choose zener diode value as maximum voltage range of meter)

Zener diode wave shaping circuit

zener wave shaping

Here the application circuits are given for understanding purpose, if you need exact output then choose components with reference to your design.

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