LED is a Light emitting diode. These are special type of diode which emits light when it conducts with electrical supply or current. LED comes in different size and shape and color. Now a day’s LED's are used as indicator in electronics circuit to illumination purpose in automobile industry to light bulb in houses.  LED is used in making Flat Numeric Display also known as 7-segment display and in dot matrix display. Multi color RGB LED is used in digital signage boards.