What is Zener Diode, Zener knee and break down voltage

Definition of Zener Diode

A zener diode is p-n junction a silicon diode which is operated in only reverse breakdown region.

The symbol of Zener diode is as below

Zener knee

At a certain voltage in reverse bias condition ,the reverse breakdown occurs and current increases rapidly. This sharp change in zener current is called as knee or zener knee of the reverse characteristics.

Zener Breakdown Voltage

The reverse bias voltage at which the breakdown occurs is called zener breakdown voltage, denoted as V This value is carefully designed by controlling the doping level during manufacturing.

Izmin and Izmax

Practically two currents are specified:
Izmin is minimum current through the zener diode to maintain its operation while Izmax  is maximum current allowed to flow in zener diode.

Read What is p-n junction diode