Incandescent
Incandescent lamps are the most familiar light source. They owe their popularity to their
low cost, good color rendering, compact size, wide range of shapes and wattages and the
fact that they are easily dimmed. Dimming causes incandescent lamps to run at lower
temperatures, which results in longer lamp life, but also in a warmer color. 
| Halogen
Halogen lamps are a type of
incandescent lamp that is filled with a halogen gas, allowing the lamp to burn more
intensely, with a whiter light, and a slightly higher efficacy then ordinary incandescent.
Moreover, the "halogen cycle" redeposits the evaporated tungsten filament, so
that blackening is avoided and output is maintained throughout the life of the lamp.
| Low
Voltage
Incandescent lamps designed to run
at 12 volts are increasingly common, especially low voltage lamps, because of their
advantages: a smaller filament, permitting more precise beam control, smaller bulb size,
smaller fixture size and whiter light.
Low voltage lamps require a transformer; this is normally part of the fixture, but
sometimes it is remote, and because the life of low voltage lamps is dependent on the
voltage with which they are operated, the transformer rating and the lamp wattage should
be closely matched. Electronic transformers have advantages over magnetic types,
especially when incorporated in the fixture: they are smaller, lighter and quieter. 
| Fluorescent
Fluorescent lamps are much more efficient then incandescent, and therefore use much less
energy for the same light output, as much as 80% less. They also last 10 - 20 times as
long as incandescent.
Fluorescent lamps require a ballast, whose function is to start the lamp and control its
operation. Electronic ballasts, which are replacing the older magnetic type, eliminate hum
and flicker and are more efficient, smaller and lighter. The also make dimming more
affordable.
With the advent of better color-rendering and new electronic technology, applications of
fluorescent in the home, and other "people-oriented" spaces, are increasing
rapidly. 
|
