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Light
Sources
The
performance of any light fixture depends very much
on the light source (bulb) used. Different sources
produce different effects. Light is measured in terms
of:
Wattage
The amount of electricity consumed by
a bulb.
Lumens
The amount of light that a bulb produces.
Footcandles
The amount of light reaching a subject.
Incandescent
GENERAL
SERVICE
General
service bulbs are inexpensive and readily available
in a variety of wattages and shapes. They produce
a yellowish-white light that is emitted in all directions.
Available in either clear or frosted.
Types:
General
(A)
Globe (G)
Decorative (D) (flame, teardrop, and other shapes)
REFLECTORIZED
Reflective
coating inside the bulb directs light forward, giving
you better beam control than general service bulbs.
Flood types (FL) spread light. Spot types (SP) concentrate
the light.
Reflector
(R) bulbs put approximately double the amount
of light (footcandles) on the subject as General Service
(A) of same wattage.
Parabolic
Reflector (PAR) bulbs control light more precisely.
They produce about four times the light of General
Service (A) and are used in recessed and track lighting.
Weatherproof casing makes them suitable for outdoor
spot and flood fixtures.
Tungsten-Halogen
Produces
a bright, white light. Has longer life and provides
more light (lumens) per watt than regular incandescent
bulbs. Maintains maximum efficiency throughout life
of bulb. Available in both line- (120 volts) and low-voltage
(12 volts). Low-voltage types require a transformer
to step down the voltage. Among the most popular tungsten-halogen
bulbs are:
LINE
VOLTAGE
PAR
16, 20, 30 and 38 reflectorized
bulbs provide better beam control than regular incandescent
PAR bulbs. Available in numerous spot and flood beam
spreads. Used in track, recessed, and outdoor spot,
and floodlights.
T-3
Double-Ended bulbs are available in a variety
of base types and are used in wall sconces, torchiers,
and outdoor flood lights. The direction of the light
is controlled by the fixture.
T-4
Single-Ended bulbs come in both "mini-can"
and "bayonet" base types and are used in
wall sconces, bath brackets, torchiers, and pendants.
The direction of the light is controlled by the fixture.
LOW-VOLTAGE
MR-11,
MR-16 (Mini-Reflectors)
provide excellent beam control. Available in numerous
spot and flood beam spread. Miniature size permits
use in smaller track and recessed fixtures. Also used
in outdoor spotlights.
PAR-36
provides superior beam control, especially over longer
distances. Available in a broad selection of spot
and flood beam spread. Used in track, recessed, and
outdoor fixtures.
T-4
Bipin, also known as a "peanut" bulb,
is a miniature lamp used in pendants, halogen desk
lamps, and some track fixtures. The direction of the
light is controlled by the fixture.
Fluorescent
Use
1/5 to 1/3 as much electricity as incandescents with
comparable lumen ratings and last up to 20 times longer.
Compact types are used in smaller, trimmer fixtures
such as recessed downlights, wall sconces, close-to-ceiling
fixtures, and track lights. Screw-in types can be
used in place of incandescents in standard lamp sockets.
Available in a wide spectrum of colors. Warm white
tones best duplicate the color of incandescents.
High-Intensity
Discharge
High-intensity
discharge (hid) bulbs have a longer life and provide
more light (lumens) per watt than any other light
source. Available in mercury vapor, metal halide,
high- and low-pressure sodium types. Used residentially
for outdoor security and landscape lighting.
This
is just an overview of the wide variety of light sources
that are on the market. For help in determining what
bulbs to use in specific applications, talk to the
Certified Lighting Consultants at our showroom. They
can help you choose the best available light sources
to suit your needs.
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