Question

The use of zener diode is as ________.

Answer 1

Voltage Regulator.

The Zener diode, when biased in the forward direction it behaves just like a normal signal diode passing the rated current, but as soon as a reverse voltage applied across the Zener diode exceeds the rated voltage of the device, the diode's breakdown voltage is reached at which point a process called Avalanche Breakdown occurs in the semiconductor depletion layer and a current starts to flow through the diode to limit this increase in voltage.

The current now flowing through the Zener diode increases dramatically to the maximum circuit value (which is usually limited by a series resistor) and once achieved this reverse saturation current remains fairly constant over a wide range of applied voltages. The voltage point at which the voltage across the Zener diode becomes stable is called the “Zener voltage”.