LED is referred as Light-emitting diode. It is made of a compound containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N), etc.LED is referred as Light-emitting diode. It is made of a compound containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N), etc.

 

When the electrons and holes combined to radiate visible light, and that can be used to make light-emitting diodes. LED can be used as indicator light in the circuit and instrument, or composed to display text or digits. Gallium arsenide gives red light, gallium phosphide emits green, silicon carbide gives yellow, gallium nitride emits blue. LED can also be divided as organic light-emitting diode OLED and inorganic light-emitting diode LED due to its chemical nature.