zenerdiódát

A zenerdióda is a type of semiconductor diode specifically designed to operate in the reverse breakdown region. Unlike a standard diode that is typically used for rectification and is avoided in its breakdown state, the zenerdióda is intentionally utilized for this characteristic. When a zenerdióda is reverse-biased and the voltage across it reaches a specific value, known as the zener voltage, it begins to conduct current. This conduction occurs while maintaining a nearly constant voltage across the diode, regardless of significant fluctuations in the current or the applied voltage. This stable voltage characteristic is the primary reason for its widespread use.

The mechanism behind this stable breakdown is attributed to two distinct effects, depending on the zener voltage. For diodes with lower zener voltages (typically below 5.5 volts), the zener effect predominates. This effect involves a strong electric field that directly pulls electrons from their covalent bonds, causing them to become free and conduct current. For diodes with higher zener voltages, the avalanche effect is more significant. In this scenario, free electrons accelerated by the electric field collide with other atoms, knocking out more electrons, leading to a cascade or avalanche of charge carriers.

The primary application of a zenerdióda is in voltage regulation. By connecting a zenerdióda in reverse bias parallel to a load, it can maintain a stable voltage across that load. Any excess voltage is absorbed by the zener dióda, and any drop in the source voltage might cause the zener dióda to stop conducting, but as long as the input voltage is above the zener voltage, the output will remain regulated. They are also used in surge protection circuits and as voltage references in electronic circuits.