Light emitting diode(LED) is a semiconductor light source. It is used in light appearing electronic components. Earlier LED’s emitted low intensity red light but modern versions are available in visible, ultraviolet and infrared wavelengths with high brightness. When a light emitting diode is switched on, electrons are able to recombine with holes within the device, releasing energy in form of photons. This effect is called electroluminescence. Modern LED’s has many advantages including low energy consumption, longer lifetime, faster switching.

¬†The first commercial LED’s were commonly used as replacements for incandescent and neon indicator lamps and seven segmented displays. LED performance is temperature dependent. LED’s emits less heat compared to incandescent bulbs. The three types of LED’s are miniature, mid range and high power.