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
Sony optimistic on 3-D TVs, in-house display
Nov 26, 2009 |
4.7 / 5 (3) |
0
(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.
Search results for led
Pork meat grown in the laboratory
3 hours ago |
4.6 / 5 (9) |
3
(PhysOrg.com) -- Scientists from Eindhoven University in The Netherlands have for the first time grown pork meat in the laboratory by extracting cells from a live pig and growing them in a petri dish.
Ambulatory surgical centers may exceed performance of hospitals for certain procedures
3 hours ago |
not rated yet |
0
Measuring five quality-base performance areas, an ambulatory surgical center out performed a standard hospital based surgical center in otolaryngic surgeries, according to new research in the December 2009 issue of Otolaryngology - ...
Scientists trace shark fins to their geographic origin for first time using DNA tools
4 hours ago |
not rated yet |
0
Millions of shark fins are sold at market each year to satisfy the demand for shark fin soup, a Chinese delicacy, but it has been impossible to pinpoint which sharks from which regions are most threatened ...
Grant to help zoo visitors learn more about science with their cell phones
14 hours ago |
not rated yet |
0
Zoo visitors may soon use their cell phones to "Call the Wild" as part of a project led by University of Florida researchers to help the public learn more about the nature of science.
Study Examines Racial 'Blind Spots' in Chicago Area Communities
Other Sciences / Social Sciences
16 hours ago |
5 / 5 (1) |
2
(PhysOrg.com) -- Racial residential segregation in the Chicago area may be perpetuated by a lack of knowledge of communities across racial lines, according to a new study led by a University of Illinois at Chicago researcher.
Study describes new tool in the fight against autoimmune diseases, blood cancers
16 hours ago |
not rated yet |
0
A study led by a Scripps Research Institute scientist describes a new, highly pragmatic approach to the identification of molecules that prevent a specific type of immune cells from attacking their host. The findings add ...
Distrust of Men Doesn't Keep Low-Income Mothers from Romantic Unions
Other Sciences / Social Sciences
16 hours ago |
3.3 / 5 (3) |
1
(PhysOrg.com) -- Contrary to popular scholarship that attributes low rates of marriage among low-income mothers to their general distrust of men, a new study led by a Duke University sociologist finds that gender distrust ...
Improving Cardiac Rehab for Women with Heart Disease
17 hours ago |
not rated yet |
0
(PhysOrg.com) -- USF Health researcher shows motivational "women-only" cardiac rehab improves symptoms of depression.
Scientists reveal malaria parasites' tactics for outwitting our immune systems
17 hours ago |
5 / 5 (2) |
0
Malaria parasites are able to disguise themselves to avoid the host's immune system, according to research funded by the Wellcome Trust and published today in the journal Proceedings of the National Academy of ...
Study: Believers' inferences about God's beliefs are uniquely egocentric
Medicine & Health / Psychology & Psychiatry
18 hours ago |
4.2 / 5 (21) |
23
Religious people tend to use their own beliefs as a guide in thinking about what God believes, but are less constrained when reasoning about other people's beliefs, according to new study published in the ...
List of search results for led
