A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. LEDs have many advantages over incandescent light sources, including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, lighted wallpaper and medical devices.
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