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→Diodes Schottky
== Diodes Schottky ==
== Diodes Schottky ==
Another very common diode is the Schottky diode. The semiconductor composition of a Schottky diode is slightly different from a normal diode, and this results in a much smaller forward voltage drop, which is usually between 0.15V and 0.45V. They’ll still have a very large breakdown voltage though.
Schottky diodes are especially useful in limiting losses, when every last bit of voltage must be spared. They’re unique enough to get a circuit symbol of their own, with a couple bends on the end of the cathode-line.
[[Fichier:Diode-Schottky.png]]
== Zener Diodes ==
Zener diodes are the weird outcast of the diode family. They’re usually used to intentionally '''conduct reverse current'''. Zener’s are designed to have a very precise breakdown voltage, called the '''zener breakdown''' or '''zener voltage'''. When enough current runs in reverse through the zener, the voltage drop across it will hold steady at the breakdown voltage.
Taking advantage of their breakdown property, Zener diodes are often used to create a known reference voltage at exactly their Zener voltage. They can be used as a voltage regulator for small loads, but they’re not really made to regulate voltage to circuits that will pull significant amounts of current.
Zeners are special enough to get their own circuit symbol, with wavy ends on the cathode-line. The symbol might even define what, exactly, the diode’s zener voltage is. Here’s a 3.3V zener diode acting to create a solid 3.3V voltage reference:
[[Fichier:Diode-Zener.png]]
== Photodiodes ==
Photodiodes are specially constructed diodes, which capture energy from photons of light (see Physics, quantum) to generate electrical current. Kind of operating as an anti-LED.
[[Fichier:Diode-Photodiodes.jpg]]<small><br />A BPW34 photodiode (not the quarter, the little thing on top of that). Get it under the sun and it can generate about few µW’s of power!.</small>
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