LED (Light Emiting Diode)

LED is a pn diode that emits light in a wavelength region between the infra-red to ultra violet. LED has the same characteristics with diode rectifier, the difference is if the rectifier diodes out as heat energy while the LED out as energy light.

LEDs have several advantages then other light sources, that are have a solid structures, relatively small size, long lifetime, easy to use, easy to get, has the power and low prices. But the disadvantages are low intensity LED light that can not be used as a great light source. Therefore, the LED is usually used as Optocoupler, the source of light in optical communications systems and as a dysplay.

Radiation light emitted by the LED depends on the material and pn diode structure. Semiconductor materials used for the LED example:
1. Ga As (Gallium arsenide) Radiating red light
2. Ga As P (Gallium arsenide Phospide) radiating red and yellow light.
3. Ga P (Gallium Phospide) radiating red and yellow light.

Led Symbol