Light-emitting diode
hideA light-emitting diode (LED) (pronounced /ˌɛliːˈdiː/, or just /lɛd/), is an electronic light source. The LED was first invented in Russia in the 1920s, and introduced in America as a practical electronic component in 1962. Oleg Vladimirovich Losev was a radio technician who noticed that diodes used in radio receivers emitted light when current was passed through them. In 1927, he published details in a Russian journal of the first ever LED.
All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness.
LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm2) with integrated optical components to shape its radiation pattern and assist in reflection.
LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources.
Applications of LEDs are diverse. They are used as low-energy indicators but also for replacements for traditional light sources in general lighting and automotive lighting. The compact size of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are useful in communications technology.
For more information about Light-emitting diode, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with led
NXP Introduces Advanced 3DTV Processor
Dec 15, 2009 |
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NXP Semiconductors today announced the availability of the PNX5130, the industry's first video co-processor enabling 3DTV, frame-rate conversion (FRC) and local backlight dimming in a single chip. By eliminating the need ...
Sony optimistic on 3-D TVs, in-house display
Nov 26, 2009 |
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(AP) -- A third to a half of the Sony Corp. TV sets sold annually will be packed with 3-D features by the year ending March 2013, a senior executive said Thursday.
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Oceanographers image the discovery of the deepest explosive eruption on the sea floor (w/ Video)
Space & Earth / Earth Sciences
5 hours ago |
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Oceanographers using the remotely operated vehicle (ROV) Jason discovered and recorded the first video and still images of a deep-sea volcano actively erupting molten lava on the seafloor.
Gene linked to a rare form of progressive hearing loss in males is identified
8 hours ago |
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A gene associated with a rare form of progressive deafness in males has been identified by an international team of researchers funded by the National Institute on Deafness and Other Communication Disorders. The gene, PRPS1, ...
Researchers find human protein that prevents H1N1 influenza infection
9 hours ago |
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Howard Hughes Medical Institute researchers have identified a naturally occurring human protein that helps prevent infection by H1N1 influenza and other viruses, including West Nile and dengue virus.
Study shows loss of 15-42 percent of mammals in North America
9 hours ago |
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If the planet is headed for another mass extinction like the previous five, each of which wiped out more than 75 percent of all species on the planet, then North American mammals are one-fifth to one-half the way there, according ...
Facebook mines Census data to track its diversifying users
9 hours ago |
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In its earliest days, Facebook was primarily a white and Asian phenomenon. No more. In the first-ever study of the race and ethnicity of its U.S. users, Facebook said Wednesday that blacks and Latinos have joined the social ...
Study on Great Lakes erosion dredges up controversy
10 hours ago |
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The Great Lakes aren't as great as they once were. A U.S.-Canadian study released Tuesday reveals that unexpected erosion in the St. Clair River following a 1962 dredging project has permanently lowered Lakes Michigan and ...
STEM gets greener: Promoting critical thinking using renewable energy technology
10 hours ago |
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Can building model cars really help create the next generation of electric vehicle designers and engineers? Researchers at North Carolina State University think so. Through a recent grant, they will develop a curriculum that ...
Study identifies those elderly most at risk for major depression
Medicine & Health / Psychology & Psychiatry
10 hours ago |
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University of Rochester Medical Center researchers have pinpointed the prime factors identifying which elderly persons are at the highest risk for developing major depression.
Scientists crack gene code of common cancers
10 hours ago |
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Two common forms of cancer have been genetically mapped for the first time, British scientists announced, in a major breakthrough in understanding the diseases.
Supernova explosions stay in shape
11 hours ago |
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At a very early age, children learn how to classify objects according to their shape. Now, new research suggests studying the shape of the aftermath of supernovas may allow astronomers to do the same.
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