A Zener diode is a type of semiconductor diode that is designed to operate in the reverse breakdown region of its characteristic curve. Unlike regular diodes, which are designed to conduct current in the forward direction and block current in the reverse direction, Zener diodes are designed to allow current to flow in the reverse direction when a certain voltage, known as the Zener voltage, is reached.
When a Zener diode is connected in reverse bias across a voltage source, it will initially block current until the voltage across it reaches the Zener voltage. At this point, the diode will begin to conduct current, allowing it to regulate the voltage across the load connected to it. The Zener voltage is determined by the doping level of the diode, and Zener diodes are available with a wide range of voltage ratings.
Zener diodes are commonly used as voltage regulators in electronic circuits. They are used to stabilize voltage levels and prevent voltage spikes from damaging sensitive components. Zener diodes are also used in surge protectors, power supplies, and other applications where precise voltage regulation is required.