A light-emitting diode (LED) is a semiconductor device that emits narrow-spectrum light when electrically biased in the forward direction of the PN junction. This effect is a form of electroluminescence. LED displays use more power (up to 200mA) but produce more light per watt than do incandescent bulbs and work well in low light applications, which is useful in battery powered or energy-saving devices. LEDs also have the best viewing angle and can be read from virtually anywhere in the room. When environmental conditions exist, the LED’s response time is not visibly affected (“ghosting”) even at temperatures below -20 degrees Celsius.