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6.6 LED

Before going into the details of LED (Light Emitting Diode), let us understand electrical transducers and diode. 

Electrical Transducer:

An electronic device that converts energy from one form to another is called transducer. This process is called transduction.

An input transducer takes in physical energy and converts it into an electrical energy.

Example: Microphone

Takes in physical sound waves and converts into an electrical signal that can be transferred through wires.


An output transducer or an actuator takes in electrical signal and converts them into other forms of energy.

Example: Lamp 

Converts electricity into light. 

Motor converts electricity into motion. 

This transducer works to convert a form of energy (Heat, light or sound) into an electrical signal (Frequency, current and voltage).



DIODE:

A diode is a two terminal electric component that conducts electricity primarily in one direction. It has high resistance on one end and low resistance on the other end.


Uses:

Allow an electric current to pass in one direction (called the diode’s forward direction) while blocking it in the opposite direction (the reverse direction)

This unidirectional behavior is called rectification and is used to convert alternating current (AC) to Direct current (DC)

Types of Diodes:

Light Emitting diode (LED)

Laser diode

Avalanche diode

Zenne diode

Schottky diode

photo diode

PN junction diode

A diode is a semi-conductor device that essentially acts as a one-way switch for the current



LED (Light Emitting Diode)

LED (Light Emitting Diode) is a semiconductor device that emits light when an electric current flows through it. When current passes through an LED, the electrons recombine with holes emitting light in the process. LED allow the current to flow in forward direction and blocks the current in the reverse direction.


Color of an LED is determined by the Material used in Semi-conducting element

If the material used in the semi conductor element is of Aluminum gallium indium phosphide alloy then the color would be (Red, orange, yellow) and when the material used is Indium gallium nitride alloys the color would be (Green, blue, white)

Slight changes in the composition of these alloys change the color of the emitted light.

 


Watch these videos for better understanding: 

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