# Zener Diode

A zener diode is a specialized type of diode that is designed to operate in the reverse breakdown region of its voltage-current characteristic curve. When a zener diode is operated in this region, it exhibits a sharp, nearly constant voltage drop across its terminals that remains stable over a wide range of current flow. This property makes zener diodes useful as voltage regulators.

The unique behavior of a zener diode is due to the way it is constructed. Zener diodes are heavily doped with impurities, which creates a narrow depletion region in the junction between the p-type and n-type semiconductor materials. When a reverse voltage is applied to the zener diode, the electric field in the depletion region becomes strong enough to cause the free electrons to collide with the atoms in the semiconductor lattice, creating electron-hole pairs. This process, known as Zener breakdown or avalanche breakdown, results in a sudden increase in current flow through the diode and the appearance of a nearly constant voltage drop across its terminals.

## Problems from IIT JEE

Problem (JEE Mains 2016) An experiment is performed to determine the $I\text{-}V$ characteristics of a Zener diode, which has a protective resistance of $R=100$ ohm, and a maximum power dissipation rating of 1 W. The minimum voltage range of the DC source in the circuit is

1. 0-5 V
2. 0-8 V
3. 0-12 V
4. 0-24 V