A light-emitting diode (LED) is a semiconductor device based on a diode. When a forward bias voltage is applied across the LED, it switches on and releases energy in the form of light. The luminance of the output light is a function of the forward bias current that flows through the LED. Therefore, to maintain a particular luminance over the life of an LED, it is important that the current through the LED is maintained at a given value. Increasing the forward bias voltage across the diode will result in an increase in the forward bias current through the LED, which will in effect increase the luminance of the output light. LEDs come in different colors; red, green, blue, white, yellow, etc. Each colored LED has a specific forward bias voltage that is required to switch it on.