An led light bulb is a solid-state lamp that uses light-emitting diodes (leds) as the source of light. led lamps offer long service life and high energy efficiency but initial costs are higher than those of fluorescent and incandescent lamps. Chemical decomposition of led chips reduces luminous flux over life cycle as with conventional lamps.
The leds involved may be conventional semi-conductor light-emitting diodes, organic leds or polymer light-emitting diodes devices.
An assortment of led light bulbs commercially available as of 2010 as replacements for screw-in bulbs including floodlight fixtures(left), reading light (center), household lamps (center right and bottom) and low-power accent light (right) applications.
Led lightings are made to replace screw-in incandescent light bulbs. An energy-efficient bulb that claims to be the equivalent of a 60W tungsten bulb must have a minimum light output of 806 lumens. led lights are mercury-free, unlike fluorescent lamps. The higher purchase cost than other types may be more than offset by savings in energy and maintenance.
Several companies offer led lamps for general lighting purposes. The technology is improving rapidly and new energy-efficient consumer led lamps are available for wall lighting.
A light-emitting diode (led) is a semi-conductor light source. leds are used as indicator lamps in many devices and are increasingly used for other lighting. Appearing as practical electronic components in 1962, early leds emitted low-intensity red light but modern versions are available across the visible, ultraviolet and infrared wavelengths with very high brightness.
Light-emitting diodes are used in applications as diverse as aviation lighting, automotive lighting, advertising, general lighting and traffic signals. leds have allowed new text, video displays and sensors to be developed while their high switching rates are also useful in advanced communications technology. Infrared leds are also used in remote control units of many commercial products including televisions, DVD players and other domestic appliances.
With the development of high-efficiency and high-power leds, it has become possible to use leds in lighting and illumination. Replacement light bulbs have been made as well as dedicated fixtures and led lamp. leds are small, durable and need little power, so they are used in hand held devices such as flashlights, led strobe lights or camera flashes operate at a safe, low voltage, instead of 250+ volts found in xenon flash lamp based lighting.
led light bulbs could be a cost-effective option for lighting a home or office space because of their very long lifetimes.
Parts of an led
The led consists of a chip of semiconducting material doped with impurities to create a p-n junction. As in other diodes, current flows from the p-side or anode to the n-side or cathode but not in the reverse direction. Charge-carriers—electrons and holes—flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level and releases energy in the form of a photon.
Most materials used for led production have very high refractive indices. This means that much light will be reflected back into the material at the material-air surface interface. Thus, light extraction in leds is an important aspect of led production.
Buy led lights today for your walls and ceilings.
0 comments:
Post a Comment