Types of Diode

Types of diodes

Different types of diode are designed to work in different applications. Various diode available nowadays are.

Symbols of various diodes

Light emitting diodes:   A light-emitting diode (LED) is a two-terminal semiconductor diode which is used as a light source. It is a p–n junction diode that emits light when conducted and activated. When some amount of  current is applied to the terminals of LED, electrons are able to recombine with  holes within the device, releasing energy in the form of photons as they are made from special type of semiconductor like GaAs etc. light emitting diode (LED) is one of the most popular types of diode used in various application  

Laser diode:   This type of diode is different from ordinary light emitting diode because it produces a different type of light that is coherent light or laser light. Laser diodes have various application areas like DVD and CD drives to laser light pointers for presentations. Laser diodes are less expensive as compare to other forms of laser generator but still more expensive than LEDs. They have a limited lifespan.

Photodiode:   The photo-diode work opposite to LED and it is used for detecting light. It is observed that when light fall on a PN junction it generate electrons and holes. Generally, photo-diodes are operated and worked under reverse bias conditions where even small amounts of current flow resulting so that light can be easily detected.

PIN diode:   This type of diode is categorized by its construction. It is a combination of standard P-type and N-type semiconductor material and between them, there is an intrinsic semiconductor which is in its pure form and no doping. The area of the intrinsic semiconductor increases the area of the depletion region which can be used in switching applications as well as for use in photodiodes 

Schottky diodes:   is a semiconductor diode formed by the junction of a semiconductor with a metal. It has a low forward voltage drop and a very fast switching action. This type of diode has a lower forward voltage drop as compared to ordinary silicon PN junction diodes. At low currents, a range may be somewhere between 0.15 and 0.4 volts which is 0.6 volts in case of a silicon diode.

Step recovery diode is a semiconductor junction diode designed to generate extremely short pulses. It is also term as a snap-off diode or charge-storage diode or memory varactor, and application areas are microwave electronics as a pulse generator or parametric amplifier.

Tunnel diode:  a two-terminal semiconductor diode using tunneling electrons to perform high-speed switching operations today they are not widely used previously the tunnel diode was used for microwave applications

Varactor diode or varicap diode:  as a name suggests it is variable capacitance diode whose capacitance is varied by varying the reverse voltage. This type of diode is used in many radio frequency (RF) applications.

Zener diode:   The zener diode is a very useful type of diode as it provides a stable reference voltage. As a result, it has wide application areas. It is widely used in voltage regulation application it conducts in reverse bias conditions and it is observed that when a certain amount of voltage is reached it breaks down and provide a stable voltage.

Gunn Diode:  this diode is also called as a transferred electron device (TED), it is a two-terminal passive semiconductor electronic component, having a property of negative resistance, used in high-frequency electronics.