A light-emitting diode (LED) is a semiconductor light source 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. Modern LEDs are available in visible, ultraviolet (UV), and infrared wavelengths, with high light output.
Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. Recent developments have produced high-output white light LEDs suitable for room and outdoor area lighting. LEDs have led to new displays and sensors, while their high switching rates are useful in advanced communications technology.
LEDs have many advantages over incandescent light sources, including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. LEDs are used in 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.Unlike a laser, the light emitted from an LED is neither spectrally coherent nor even highly monochromatic. However, its spectrum is sufficiently narrow that it appears to the human eye as a pure (saturated) color. Also unlike most lasers, its radiation is not spatially coherent, so it cannot approach the very high brightnesses characteristic of lasers.
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Having "googled" into this thread, I was hoping you could help with my own "LED lighting" question. I have a cost-sensitive instrument application where I need to supply roughly 50mW to an assembly rotating on a motor shaft, about 6mm from the nearest support.
I wondered if I could...
I've been doing a ton of research recently on how lasers work.
Basically a laser is actually L.A.S.E.R which stands for "Light Amplified of Stimulated emitted radiation".
A laser is cohernet, which means it is only its wavelengths are not fixed.
Low power red lasers are often known as...
hey guys,
I have been looking to make a outdoor led washlight for a long time now. I am not very experienced with electronic circuts but I can understand the basics. I am planning to have 30 leds, 10 each of red green blue. I want to control the three different colors with a potentiometer...