How Does a Zener Diode Work?

The mechanism of a zener diode works by using a reverse bias connection, which results in a breakdown that allows electrical conduction. The principle behind this mechanism is known as the zener effect, named after the American physicist Clarence Zener.

A diode is an electronic device comprising of semiconductors that are classified as either p-type or n-type. The p-type semiconductor is positively charged and contains an excess number of holes, while the n-type semiconductor is negatively charged and contains an excess number of electrons. The boundary between the two semiconductor types is called the p-n junction. A normal diode typically allows electrical current to pass through by using a forward bias connection.

The zener diode, also known as breakdown diode, typically uses a silicon p-n junction that is biased in the reverse direction. In a reverse bias connection, the applied voltage inhibits electrical flow. However, by continually increasing the voltage, the diode eventually reaches its breakdown point when the depletion layer at the p-n junction disintegrates. This breakdown results to an electrical flow across the diode to control the high reverse voltage. The breakdown voltage point at which a zener diode allows electrical current to flow is known as zener voltage. Zener diodes are primarily used as voltage regulators.