A light-emitting-diode lamp is a solid-state lamp that uses light-emitting diodes (LEDs) as the source of light. Since the light output of individual light-emitting diodes is small compared to incandescent and compact fluorescent lamps, multiple diodes are used together. LED lamps can be made interchangeable with other types. Most LED lamps must also include internal circuits to operate from standard AC voltage. LED lamps offer long life and high efficiency, but initial costs are higher than that of fluorescent lamps.Application
LED lamps are used for both general lighting and special purpose lighting. Where colored light is required, LEDs come in multiple colors, which are produced without the need for filters. This improves the energy efficiency over a white light source that generates all colors of light then discards some of the visible energy in a filter.
White-light light-emitting diode lamps have the characteristics of long life expectancy and relatively low energy consumption. The LED sources are compact, which gives flexibility in designing lighting fixtures and good control over the distribution of light with small reflectors or lenses. LED lamps have no glass tubes to break, and their internal parts are rigidly supported, making them resistant to vibration and impact. With proper driver electronics design, an LED lamp can be made dimmable over a wide range; there is no minimum current needed to sustain lamp operation. LEDs using the color-mixing principle can produce a wide range of colors by changing the proportions of light generated in each primary color. This allows full color mixing in lamps with LEDs of different colorsLED lamps contain no mercury.
However, some current models are not compatible with standard dimmers. It is not currently economical to produce high levels of lighting. As a result, current LED screw-in light bulbs offer either low levels of light at a moderate cost, or moderate levels of light at a high cost. In contrast to other lighting technologies, LED light tends to be directional. This is a disadvantage for most general lighting applications, but can be an advantage for spot or flood lighting.
LED lamps are used for both general lighting and special purpose lighting. Where colored light is required, LEDs come in multiple colors, which are produced without the need for filters. This improves the energy efficiency over a white light source that generates all colors of light then discards some of the visible energy in a filter.
White-light light-emitting diode lamps have the characteristics of long life expectancy and relatively low energy consumption. The LED sources are compact, which gives flexibility in designing lighting fixtures and good control over the distribution of light with small reflectors or lenses. LED lamps have no glass tubes to break, and their internal parts are rigidly supported, making them resistant to vibration and impact. With proper driver electronics design, an LED lamp can be made dimmable over a wide range; there is no minimum current needed to sustain lamp operation. LEDs using the color-mixing principle can produce a wide range of colors by changing the proportions of light generated in each primary color. This allows full color mixing in lamps with LEDs of different colorsLED lamps contain no mercury.
However, some current models are not compatible with standard dimmers. It is not currently economical to produce high levels of lighting. As a result, current LED screw-in light bulbs offer either low levels of light at a moderate cost, or moderate levels of light at a high cost. In contrast to other lighting technologies, LED light tends to be directional. This is a disadvantage for most general lighting applications, but can be an advantage for spot or flood lighting.
The LED light bulb
As of 2010, only a few LED light bulb options are available as replacements for the ordinary household incandescent or compact fluorescent light bulb. One drawback of the existing LED bulbs is that they offer limited brightness, with the brightest bulbs equivalent to a 45-60 W incandescent bulb. Most LED bulbs are not able to be dimmed, and their brightness retains some directionality. The bulbs are also expensive, costing $40–50 per bulb, whereas the ordinary incandescent bulb costs less than a dollar. However, these bulbs are slightly more power efficient than the compact fluorescent bulbs and offer extraordinary lifespans of 30,000 or more hours. An LED light bulb can be expected to last 25–30 years under normal use. LED bulbs will not dim over time and they are mercury free, unlike the compact fluorescent bulbs. Recent research has made bulbs available with a variety of color characteristics, much like the incandescent bulb. With the savings in energy and maintenance costs, these bulbs can be attractive. It is expected that with additional development and growing popularity, the cost of these bulbs will eventually decline.
Fluorescent tubes with modern electronic ballasts commonly average 50 to 67 lumens/W overall. Most compact fluorescents rated at 13 W or more with integral electronic ballasts achieve about 60 lumens/W, comparable to the LED bulb. A 60 W incandescent bulb offers about 850 lumens, or 14 lumens/W.
Several companies offer LED lamps for general lighting purposes. The C. Crane Company has a product called "Geobulb". The GeoBulb II uses only 7.5 W (59 lumens/W). In October 2009, the GeoBulb II was superseded by the GeoBulb-3 which is brighter and longer lasting.The company also offers wedge-base lamps for replacement in low voltage fixtures. In the Netherlands, a company called Lemnis Lighting offers a dimmable LED lamp called Pharox. The company Eternleds Inc. offers a bulb called HydraLux-4 which uses liquid cooling of the LED chips.
As of 2010, only a few LED light bulb options are available as replacements for the ordinary household incandescent or compact fluorescent light bulb. One drawback of the existing LED bulbs is that they offer limited brightness, with the brightest bulbs equivalent to a 45-60 W incandescent bulb. Most LED bulbs are not able to be dimmed, and their brightness retains some directionality. The bulbs are also expensive, costing $40–50 per bulb, whereas the ordinary incandescent bulb costs less than a dollar. However, these bulbs are slightly more power efficient than the compact fluorescent bulbs and offer extraordinary lifespans of 30,000 or more hours. An LED light bulb can be expected to last 25–30 years under normal use. LED bulbs will not dim over time and they are mercury free, unlike the compact fluorescent bulbs. Recent research has made bulbs available with a variety of color characteristics, much like the incandescent bulb. With the savings in energy and maintenance costs, these bulbs can be attractive. It is expected that with additional development and growing popularity, the cost of these bulbs will eventually decline.
Fluorescent tubes with modern electronic ballasts commonly average 50 to 67 lumens/W overall. Most compact fluorescents rated at 13 W or more with integral electronic ballasts achieve about 60 lumens/W, comparable to the LED bulb. A 60 W incandescent bulb offers about 850 lumens, or 14 lumens/W.
Several companies offer LED lamps for general lighting purposes. The C. Crane Company has a product called "Geobulb". The GeoBulb II uses only 7.5 W (59 lumens/W). In October 2009, the GeoBulb II was superseded by the GeoBulb-3 which is brighter and longer lasting.The company also offers wedge-base lamps for replacement in low voltage fixtures. In the Netherlands, a company called Lemnis Lighting offers a dimmable LED lamp called Pharox. The company Eternleds Inc. offers a bulb called HydraLux-4 which uses liquid cooling of the LED chips.
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