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What is LED? & how are they different from most others...
A fluorescent lamp or fluorescent tube is a
gas-discharge lamp that uses
electricity to
excite
mercury
vapor. The excited mercury
atoms produce short-wave
ultraviolet light that then
causes a
phosphor to
fluoresce, producing
visible light.
Unlike
incandescent lamps,
fluorescent lamps always require a
ballast to regulate the flow
of power through the lamp. However, a fluorescent lamp converts
electrical power into useful light more efficiently than an
incandescent lamp. Lower energy cost typically offsets the higher
initial cost of the lamp. While larger fluorescent lamps have been
mostly used in large commercial or institutional buildings, the
compact fluorescent lamp is
now being used as an energy-saving alternative to incandescent
lamps in homes. Compared with incandescent lamps, fluorescent
lamps use less power for the same amount of light, generally last
longer, but are bulkier, more complex, contain trace amounts of
mercury, and initially more expensive than a comparable
incandescent lamp.
A lamp is a replaceable component such as an
incandescent light bulb, which
is designed to produce
light from
electricity. These components
usually have a base of ceramic, metal, glass or plastic, which
makes an electrical connection in the socket of a
light fixture. This connection
may be made with a screw-thread base, two metal pins, 2 metal caps
or a bayonet cap. Re-lamping is the replacement of only the
removable lamp in a light fixture.
The incandescent light bulb, incandescent
lamp or incandescent light globe is a source of electric
light
that works by
incandescence
(a general term for heat-driven light emissions which includes the
simple case of
black body
radiation). An
electric current
passes through a thin
filament,
heating it until it produces light. The enclosing glass bulb
prevents the
oxygen in air from reaching the hot
filament, which otherwise would be destroyed rapidly by
oxidation.
Incandescent bulbs are also sometimes called electric lamps,
a term also applied to the original
arc lamps.
Incandescent bulbs are made in a wide range
of sizes and
voltages,
from 1.5 volts to about 300 volts. They require no external
regulating equipment and have a low manufacturing cost, and work
well on either alternating current or direct current. As a result
the incandescent lamp is widely used in household and commercial
lighting, for portable lighting, such as table lamps, some car
headlamps
and electric
flashlights,
and for decorative and advertising lighting.
Some applications of the incandescent bulb
make use of the heat generated, such as incubators, brooding boxes
for
poultry,
heat lights for
reptile
tanks,
infrared heating
for industrial heating and drying processes, and the
Easy-Bake Oven
toy. In cold weather the heat shed by incandescent lamps
contributes to building heating, but in hot climates lamp losses
increase the energy used by
air conditioning
systems.
Incandescent light bulbs are gradually being
replaced in many applications by other types of
electric light
such as (compact)
fluorescent lamps,
high-intensity discharge lamps,
light-emitting diodes
(LEDs), and other devices. These newer technologies give more
visible light for the same amount of electrical energy input, and
often generate much less heat. Some jurisdictions, such as the
European Union
are in the process of
phasing-out the use of incandescent
light bulbs in favor of more
energy-efficient lighting
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