DIODE

what is your function?

convert alternating current (AC) into direct current (DC).

Concept

Diodes are electronic pieces that have two electrodes and that allow the advance of electrical current in only one direction.

History

Diodes were the first semiconductor electronic devices. The discovery of crystals' rectifying abilities was made by German physicist Ferdinand Braun in 1874.

Structure

The diode is a two-layer, two-terminal semiconductor device. When n-type and p-type semiconductor material are joined together, this forms a PN junction, which is referred to as a diode.

N-type

Positively charged

P-type

Negatively charged

There are two types of bias voltage

Forward biased

Reversed biased P N

DIODE TYPES

Avalanche Diode

The Avalanche diode is a P-N junction diode that is specifically designed to operate in the avalanche breakdown region.

P-N Junction Diode

It consists of two layers of semiconductors. One layer is doped with P-type material and the other layer with N-type material. The combination of these both P and N-type layers form a junction known as the P-N junction.

Rectifier Diode

A rectifier diode is a type of P-N junction diode, whose P-N junction area is very large. This results in high capacitance in reverse direction. It has low switching speed.

Light Emitting Diode (LED)

The light emitting diode is also a type of P-N junction diode that emits light in the forward bias configuration.

Photodiode

The photodiode is a type of P-N junction diode that converts the light energy into electrical current. Its operation is opposite to that of an LED.

Laser Diode

A laser diode is similar to LED because it converts electrical energy into light energy. But unlike LED, Laser diode produces coherent light.

Tunnel Diode

The Tunnel diode has a region in its VI curve where the current decreases as the voltage increases. This region is known as the negative resistance region.

Zener Diode

The Zener diode has heavier doping concentration than a normal P-N junction diode. Hence, it has a very thin depletion region.

Backward Diode

The backward diode or the back diode is a P-N junction diode, whose operation is similar to that of tunnel diode and Zener diode. But the operating voltages are much lower.