Understanding Zener Diodes

A Zener diode is a semiconductor device that permits current to flow in the forward direction like a typical diode, but also in the reverse direction if the voltage exceeds a certain value known as the breakdown voltage.

The Zener breakdown occurs due to electron quantum tunnelling caused by a high electric field. Unlike regular diodes, Zener diodes are designed to withstand reverse voltage breakdown without damage.

Zener diodes are widely used for voltage regulation. They maintain a constant voltage output in electronic circuits, even when the supply voltage varies or the load connected to the output changes.

Zener diodes have a sharp, highly doped p-n junction, creating a low breakdown voltage. When reverse-biased, the sharp breakdown voltage characteristic enables the diode to stabilize voltage.

Besides voltage regulation, Zener diodes are used in surge protectors, clipping circuits, and to generate reference voltage levels for analog-to-digital converters.

Some Zener diodes are designed to have a temperature coefficient close to zero, making them ideal for use in temperature-compensated reference elements in precision applications.

Zener diodes can dissipate limited power before overheating, necessitating heat sinks for dissipation. Excessive power dissipation can lead to thermal runaway and diode failure.