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In electronics, the Zener effect (employed most notably in the appropriately named Zener diode) is a type of electrical breakdown, discovered by Clarence Melvin Zener. It occurs in a reverse biased p-n diode when the electric field enables tunneling of electrons from the valence to the conduction band of a semiconductor , leading to numerous ...
The Zener diode exhibits an apparently similar effect in addition to Zener breakdown. Both effects are present in any such diode, but one usually dominates the other. Avalanche diodes are optimized for avalanche effect, so they exhibit small but significant voltage drop under breakdown conditions, unlike Zener diodes that always maintain a ...
In principle, avalanche breakdown only involves the passage of electrons and need not cause damage to the crystal. Avalanche diodes (commonly encountered as high voltage Zener diodes) are constructed to break down at a uniform voltage and to avoid current crowding during breakdown. These diodes can indefinitely sustain a moderate level of ...
The Zener diode is therefore well suited for applications such as the generation of a reference voltage (e.g. for an amplifier stage), or as a voltage stabilizer for low-current applications. [2] Another mechanism that produces a similar effect is the avalanche effect as in the avalanche diode. [2]
Reverse-biased diodes in breakdown can also be used as shot noise sources. Voltage regulator diodes are common, but there are two different breakdown mechanisms, and they have different noise characteristics. The mechanisms are the Zener effect and avalanche breakdown. [9]
In fact, Zener diodes are essentially just heavily doped normal diodes that exploit the breakdown voltage of a diode to provide regulation of voltage levels. Rectifier diodes (semiconductor or tube/valve) may have several voltage ratings, such as the peak inverse voltage (PIV) across the diode, and the maximum RMS input voltage to the rectifier ...
Avalanche diodes These are diodes that conduct in the reverse direction when the reverse bias voltage exceeds the breakdown voltage. These are electrically very similar to Zener diodes (and are often mistakenly called Zener diodes), but break down by a different mechanism: the avalanche effect. This occurs when the reverse electric field ...
Designers must rely on a diode's specification sheet, which primarily provides a maximum forward voltage drop at one or more forward currents, a reverse leakage current (or saturation current), and a maximum reverse voltage limited by Zener or avalanche breakdown. Effects of temperature and process variation are usually included. Typical examples: