Qué (quién) es LED - definición
![Lumileds]])](https://commons.wikimedia.org/wiki/Special:FilePath/2007-07-24 High-power light emitting diodes (Luxeon, Lumiled).jpg?width=200 "Lumileds]])")
![[[Blue]] LEDs](https://commons.wikimedia.org/wiki/Special:FilePath/Blue light emitting diodes over a proto-board.jpg?width=200 "[[Blue]] LEDs")
![mains voltage]]](https://commons.wikimedia.org/wiki/Special:FilePath/Br20 1.jpg?width=200 "mains voltage]]")
![Illustration of [[Haitz's law]], showing improvement in light output per LED over time, with a logarithmic scale on the vertical axis](https://commons.wikimedia.org/wiki/Special:FilePath/Haitz-law.svg?width=200 "Illustration of [[Haitz's law]], showing improvement in light output per LED over time, with a logarithmic scale on the vertical axis")
 8.5.4.2.svg?width=200)
.svg?width=200 "Parts of a conventional LED. The flat bottom surfaces of the anvil and post embedded inside the epoxy act as anchors, to prevent the conductors from being forcefully pulled out via mechanical strain or vibration.")
![[[Daytime running light]] LEDs of an automobile](https://commons.wikimedia.org/wiki/Special:FilePath/LED DaytimeRunningLights.jpg?width=200 "[[Daytime running light]] LEDs of an automobile")
![Los Angeles [[Vincent Thomas Bridge]] illuminated with blue LEDs](https://commons.wikimedia.org/wiki/Special:FilePath/Los Angeles Bridge.jpg?width=200 "Los Angeles [[Vincent Thomas Bridge]] illuminated with blue LEDs")
![Round]]'s original experiment from 1907.](https://commons.wikimedia.org/wiki/Special:FilePath/SiC LED historic.jpg?width=200 "Round]]'s original experiment from 1907.")
![surface mount LED]]s in most common sizes. They can be much smaller than a traditional 5{{nbsp}}mm lamp type LED, shown on the upper left corner.](https://commons.wikimedia.org/wiki/Special:FilePath/Single and multicolor surface mount miniature LEDs in most common sizes.jpg?width=200 "surface mount LED]]s in most common sizes. They can be much smaller than a traditional 5{{nbsp}}mm lamp type LED, shown on the upper left corner.")
![surface mount LED]]](https://commons.wikimedia.org/wiki/Special:FilePath/Surface mount LED close up image.png?width=200 "surface mount LED]]")
![LEDs are produced in a variety of shapes and sizes. The color of the plastic lens is often the same as the actual color of light emitted, but not always. For instance, purple plastic is often used for infrared LEDs, and most blue devices have colorless housings. Modern high-power LEDs such as those used for lighting and backlighting are generally found in [[surface-mount technology]] (SMT) packages (not shown).](https://commons.wikimedia.org/wiki/Special:FilePath/Verschiedene LEDs.jpg?width=200 "LEDs are produced in a variety of shapes and sizes. The color of the plastic lens is often the same as the actual color of light emitted, but not always. For instance, purple plastic is often used for infrared LEDs, and most blue devices have colorless housings. Modern high-power LEDs such as those used for lighting and backlighting are generally found in [[surface-mount technology]] (SMT) packages (not shown).")
![Very small (1.6×1.6×0.35{{nbsp}}mm) red, green, and blue surface mount miniature LED package with gold [[wire bonding]] details.](https://commons.wikimedia.org/wiki/Special:FilePath/Very small 1.6x1.6x0.35 mm RGB Surface Mount LED EAST1616RGBA2.jpg?width=200 "Very small (1.6×1.6×0.35{{nbsp}}mm) red, green, and blue surface mount miniature LED package with gold [[wire bonding]] details.")
![Stokes-shifted]] light emitted by the Ce<sup>3+</sup>:YAG phosphor, which emits at roughly 500–700 nm](https://commons.wikimedia.org/wiki/Special:FilePath/White LED.png?width=200 "Stokes-shifted]] light emitted by the Ce<sup>3+</sup>:YAG phosphor, which emits at roughly 500–700 nm")
![A large LED display behind a [[disc jockey]]](https://commons.wikimedia.org/wiki/Special:FilePath/LED screen behind Tsach Zimroni in Tel Aviv Israel.jpg?width=200 "A large LED display behind a [[disc jockey]]")
![[[Seven-segment display]] that can display four digits and points](https://commons.wikimedia.org/wiki/Special:FilePath/LED Digital Display.jpg?width=200 "[[Seven-segment display]] that can display four digits and points")
![LED panel light source used in an early experiment on [[potato]] growth during Shuttle mission [[STS-73]] to investigate the potential for growing food on future long duration missions.](https://commons.wikimedia.org/wiki/Special:FilePath/LED panel and plants.jpg?width=200 "LED panel light source used in an early experiment on [[potato]] growth during Shuttle mission [[STS-73]] to investigate the potential for growing food on future long duration missions.")
Wikipedia
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.
Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. Later developments produced LEDs available in visible, ultraviolet (UV), and infrared wavelengths, with high, low, or intermediate light output, for instance white LEDs suitable for room and outdoor area lighting. LEDs have also given rise to new types of displays and sensors, while their high switching rates are useful in advanced communications technology with applications as diverse as aviation lighting, fairy lights, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, lighted wallpaper, horticultural grow lights, and medical devices.
LEDs have many advantages over incandescent light sources, including lower power consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. In exchange for these generally favorable attributes, disadvantages of LEDs include electrical limitations to low voltage and generally to DC (not AC) power, inability to provide steady illumination from a pulsing DC or an AC electrical supply source, and lesser maximum operating temperature and storage temperature. In contrast to LEDs, incandescent lamps can be made to intrinsically run at virtually any supply voltage, can utilize either AC or DC current interchangeably, and will provide steady illumination when powered by AC or pulsing DC even at a frequency as low as 50 Hz. LEDs usually need electronic support components to function, while an incandescent bulb can and usually does operate directly from an unregulated DC or AC power source.
As a transducer of electricity into light, LEDs operate in reverse of photodiodes.
