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A light-emitting diode (LED) is a device that emits light when an electric current passes through it. LEDs first appeared in 1962 as practical electronic components that only emitted low intensity red light. Modern versions can be very bright and are available in a broad spectrum of colors in the visible and even in the ultraviolet and infrared spectrums. They are mainly used in various electronic devices like watches, flashlights, cellphones, displays and many more. Because they have a longer life span and are more energy efficient than regular light bulbs, they have mostly replaced them, especially in household settings.
The LED emerged from the discovery of electroluminescence by British scientist H.J. Round in Marconi Labs in 1907. Then in 1961, Gary Pittman and Robert Biard conducting experiments at Texas Instruments discovered that gallium arsenide emitted infrared radiation during the application of electrical current; they subsequently patented the infrared LED. The first visible light LED (red) came later in 1962. It developed by Nick Holonyak Jr. while working in General Electric. Holonyak became known as the "father of the light-emitting diode". In1972, M. George Craford, who had been one of Holonyak's students, invented the yellow LED and improved the light output of the red and red-orange LEDs by a factor of 10.
LEDs have a few key advantages over incandescent lights: