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ANSI (American National Standards Institute) |
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The organization that develops voluntary guidelines and product performance standards for the electrical and other industries. |
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Accent Lighting |
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Directional lighting used to highlight a particular object or area. |
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Alternating Current (AC) |
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Electron flow that periodically reverses polarity and direction of travel through a circuit. |
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Ambient Lighting |
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The overall lighting in an area or room. |
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Ampere (amp) |
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A standard unit of measurement of electrical current. Amps = Watts/ Voltage |
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Argon |
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Inert gas used in incandescent and
fluorescent lalmp types. In incandescent light sources, argon retards
evaporation of the filament. |
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Average Rated Life |
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An average rating, in hours, indicating
when 50% of a large group of lamps have failed, when operated at nominal
lamp voltage and current; manufacturers use 3 hours per start for
fluorescent lamps and 10 hours per start for HID lamps when performing
lamp life testing procedures; every lamp type has a unique mortality
curve that depicts its average rated life. |
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Ballast |
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A device used with an electric-discharge
lamp to obtain the necessary circuit conditions (voltage, current
and waveform) for starting and operating; all fluorescent and HID
light sources require a ballast for proper operation. |
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Ballast Factor (BF) |
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The measured ability of a particular
ballast to produce light from the lamp(s) it powers; ballast factor
is derived by dividing the lumen output of the same lamp(s) on a reference
ballast. |
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Beam Angle |
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The angle between the two directions
for which the intensity (candlepower) is 50% of the maximum intensity
as measured in a plane through the nominal beam center line. |
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Beam Spread |
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In any plane, the angle between the
two directions in the plane in which the candlepower is equal to a
stated percent of the maximum candlepower in the beam. |
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Bulb |
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Term for electrical light source or
lamp; the outer shell of the lamp. |
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Bulb Darkening |
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Darkening or discoloration of an incandescent
lamp due to tungsten particles collecting on the inside of the glass
as the filament burns and diminishes over its life. |
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Candela |
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Unit measurement of luminous
intensity. |
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Candlepower |
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The luminous intensity of a light
source expressed in candelas. |
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Cathode Guard |
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Metal band encircling the cathode
of a fluorescent lamp, used to collect the evaportating particles
from the cathode, greatly reducing end-blackening. |
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Chromaticity |
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The aspect of color that includes
consideraton of its dominant wavelength and purity. |
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Color Corrected |
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Refers to a lamp with a special phosphor
or coating to give it a color rendering profile like natural daylight. |
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Color Rendering Index (CRI) |
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A measurement to rate a lamps ability
to render an objects color. The higher the CRI, on a scale of 0-100,
the more true to life colors appear, as they would in natural daylight. |
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Color Spectrum |
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The visible light spectrum, ranging
between 380 (violet) and 770 (red) nanometers in the electromagnetic
spectrum. |
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Color Temperature |
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The actual color of a light source, also referred to as Correlated Color Temperature (CCT), measured in degrees Kelvin (K). Typical color temperature are: 2700K Incandescent |
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Cove Lighting |
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Refers to light sources mounted above
a ledge or in a recess that distribute light upward for ambient lighting. |
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Current |
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A measure of the rate of flow of electricity,
expressed in amperes (A). |
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Design Lumens |
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Lumen value at 40% of rated average
life. |
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Diffusion |
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The even redirection or spreading
of light by a lens or diffuser. |
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Down Lighting |
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A directed lighting unit, usually
small, that aims the light downward. Can be recessed, surface mounted
or suspended. |
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Efficacy |
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Referes to the efficiency of a light
source expressed in lumens per watt (LPW). The light source may be
a lamp or luminaire. |
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Electric Discharge Lamp |
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A light source that produces light
by passing a current between electrodes through a vapor or gas. Includes
fluorescent and high intensity discharge lamps. |
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Elliptical Reflector |
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Incandescent lamp with a reflector
shell which is elliptically-shaped. Focuses light immediately in front
of the lamp which reduces absorption and increased efficiency. |
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End Blackening |
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Darkening around the ends of a fluorescent
tube caused by particles evaportating from the cathode and adhering
to the glass. Lamps made with cathode guards greatly reduce this occurrence. |
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Energy Policy Act (EPACT) |
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Energy legislation passed by Congress
in 1992 mandating labeling and minimum energy efficiency requirements
for many commonly used incandescent and fluorescent lamps. |
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Energy Survey |
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Systematic cost comparison of an existing
system to a proposed system, accounting for electrical, material,
maintenance and labor costs. |
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Etch |
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Markings on the glass envelope or
shell of a lamp designating product description, logo and/or brand
name. |
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Exitance |
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The total light which comes off of
a surface. Exitance is dependent upon the illuminance on and reflectance
of the surface. |
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Eyeball |
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Fixture, usually recessed, which can
be rotated to point in a desired direction. |
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Filament |
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Wire used in incandescent lamps, usually
made of tungsten and often coiled, that emits light when heated by
an electrical current. |
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Fixture |
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Luminaire without lamps. |
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Fluorescent Lamp |
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A glass tube coated on the inside
with a fluorescent substance that gives off light when mecury vapor
in the tube is excited by a stream of electrons from the cathode. |
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Footcandle (FC) |
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A unit of measurement of direct illumination.
One footcandle is equal to one lumen per square inch. |
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Full Spectrum |
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Broad spectrum light source capable
of producing colors throughout the entire range of the visible spectrum;
simulating actual sunlight. High CRI's and Kelvin temperatures ranging
between 5500 and 5900. |
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General Lighting |
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Uniform light throughout an area,
with no special provisions for task lighting or accent lighting. |
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Halogen Cycle |
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A regenerative cycle of tunsten and
halogen atoms which prevents blackening of the lamp envelope during
the life of the lamp. |
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Head |
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Luminaire for a track-lighting system. |
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High Intensity Discharge (HID) Lamp |
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Metal Halide, High Pressure Sodium,
Low Pressure Sodium and Mercury Vapor lamp types. |
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High Output Fluorescent (HO) |
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Fluorescent lamps designed to be used
with an 800 milliampere ballast. Able to operate at low temperatures
(down to zero) and still produce high light levels. |
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High Pressure Sodium (HPS) Lamp |
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HPS lamps are high intensity discharge
light sources which produce light by an electrical discharge through
sodium vapor operating at relatively high pressures and temperatures. |
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High Voltage |
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Voltages of 208 or higher. |
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Illuminance. |
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Light arriving at a surface, expressed
in lumens per unit area; 1 lumen per square foot equals 1 footcandle,
while 1 lumen per square meters equals 1 lux. |
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Illumination |
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The results of the use of light. |
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Incandescent Lamp |
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A light source that produces light
by the heating of a filament by an electric current. |
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Inches to Millimeters Conversion |
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To calculate the metric equivalent
of inches in millimeters (mm), multiply inches by 25.4. |
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Indirect Lighting |
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Luminaires that distribute 90 - 100
percent of their light upward to be reflected by the ceiling. |
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Infrared |
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Radiant energy in the wavelength range
of about 770 to 1100 nanometers (nm). Energy in this range is not
visible to the naked eye, but can be sensed by the skin. Applications
include heat lamps, photography, medical therapy, and industry. |
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Instant Start |
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A type of fluorescent lamp-ballast
circuit designed to start fluorescent lamps as soon as the power is
applied. Originally, instant-start circuits were developed to eliminate
separate mechanical starter devices. Slimline fluorescent lamps operate
only on instant start circuits. |
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Intensity |
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The light emitted from a source. Intensity
varies given the direction at which one views the source. Intensity
does not vary with distance. |
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Kelvin Temperature |
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See color temperature. |
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Kilowatt (kw) |
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A measure of electrical power equal
to 1000 watts. |
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Kilwatt Hour (kwh) |
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The standard measurement of electrical
energy consumption. 1000 watts of electricity used in one hour. Also
the typical billing unit used by electrical utilities. |
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Krypton |
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A heavy inert gas used in incandescent
lamps which allows the filament to glow hotter and brighter and last
longer. |
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Lamp |
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Lighting industry term used for a
light bulb. |
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Lamp Dimensions |
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Bulb designations consist of a letter(s)
to indicate shape and a number to indicate the diameter in eighths
of an inch. |
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Lens |
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A glass or plastic element used in
luminaires to change the direction and control the distribution of
light rays. |
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Light |
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Radiant energy that is capable of
producing a visual sensation. |
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Light Center Length (L.C.L.) |
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The distance from a reference point,
usually the bottom of the lamp base, to the center of the light source
(filament). |
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Light Loss Factor |
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Used to calculate or project the performance
of a lighting system after a given period of time under certain conditions;
includes environmental conditions, such as temperature, voltage, dust
and/or dirt and lamp depreciation. |
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Louver |
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An assembly of slats or crosspieces
in a lighting fixture, used to control light intensity and glare. |
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Low Pressure Sodium (SOX) |
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High Intensity Discharge lamp which
uses pressurized sodium vapor to produce light. |
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Lumen |
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International unit (SI) of luminous
flux or quantity of light. Expresses quantity of light regardless
of direction. |
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Lumen Depreciation |
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The gradual decline in light output
from a light source over time. Due to filament deterioration and bulb
darkening. |
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Lumen Maintenance |
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| A measurement of how a lamp maintains
its light output over time. |
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Lumens Per Watt (LPW) |
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A measurement of the efficancy (efficiency)
of a light source. The number achieved by dividing lumens produced
by watts consumed. |
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Luminaire |
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A complete lighting unit including
lamps, housing, lens and ballast if required. All the necessary components
to make what we commonly refer to as a "fixture". |
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Luminance (L) |
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Light reflected in a particular direction;
the photometric quantity most closely associated with brightness perception,
measured in units of luminous intensity (candelas) per unit area (square
feet or square meters). |
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Lux (lx) |
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A unit of illuminance equal to 1 lumen
per square meter. |
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Maximum Overall Length (M.O.L) |
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The overall length of
a lamp, from the top tof the shell to the bottom of the base. |
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Mean Lumens |
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The average light output of a lamp
over its rated life. |
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Mercury Vapor Lamp |
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A high intensity discharge light source
operating at a relatively high pressure (about 1 atmosphere) and temperature
in which most of the light is produced by radiation from excited mercury
vapor. Phosphor coating on some lamp types add additional light and
improve color rendering. |
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Metal Halide Lamp |
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A high intensity light source in which
the light is produced by the radiation from mercury, plus halides
or metals such as sodium, scandium, indium and dysprosium. Some lamp
types may also utilize phosphor coatings. |
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Nanometer |
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A unit of length equal to 10 to the
-9th meters, or one billionth of a meter; commonly used as a unit
of wavelength. |
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Neodymium |
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Full spectrum incandescent lamps.
Also known as daylight or natural light. Uses a colored glass shell
to filter out yellow light produced by standard incandescent lamps.
see www.neodymiumbulbs.com/ |
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Nominal Length |
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A measurement for Fluorescent lamp
length, based on the length of the lamp plus an allowance for luminaires
lamp holders. |
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Ohm's Law |
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A scientific law which states that current (amperes) in a circuit depends on resistance (ohms) and applied electromotive force (volts). Current (I) = Voltage (E) / Resistance (R). |
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Operating Position |
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Lamps may be operated in any position
unless otherwise noted. |
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PAR Lamp |
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PAR is an acronym for parabolic aluminized
reflector. A PAR lamp which may utilize either an incandescent filament,
a halogen filament tube or HID arc tube is a precision pressed-glass
reflector lamp. PAR lamps rely on both the internal reflector and
prisms in the lens for the control of the light beam. |
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Phosphor |
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An inorganic chemical compound processed
into a powder and depositied on the inner glass surface of fluorescent
tubes and some mercury and metal-halide lamps. Phosphors are designed
to absorb short wavelength ultraviolet radiation and to transform
and emit it as visible light. |
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Photopic Vision |
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Refers to vision involving the cones
of the eye; used in reference to the adaptation of the eye to illuminance
of more than 3.4 candelas per square meter. |
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Power Factor |
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A measurement indicating how efficiently
a lighting system is using the power it is drawing. The ratio between
power used (watts) and power being drawn from the line (volts-amperes).
Expressed as a percent or range from 0 to 1.0. The higher the percent
the more efficiently the power is being used. High power factors are
ratings of 0.9 (90%) or higher. Incandescent lamps are close to 1.0,
magnetic ballasts can be as low as 0.5. |
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Preheat |
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A fluorescent lamp-ballast circuit
where the electrodes are heated or warmed by an auxiliary switch or
starter before the lamps light up. |
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Rapid Start |
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A fluorescent lamp-ballast circuit
which utilizes continuous cathode heating, while the system is energized,
to start and maintain lamp light output at efficient levels. Rapid
start ballasts may be either electromagnetic, electronic or of hybrid
designs. Full-range fluorescent lamp dimmming is only possible with
rapid start systems. |
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Reflector Lamp |
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An incandescent, compact fluorescent
or HID lamp with a built-in reflecting surface. Incandescent and HID
versions are made from a single piece of blow-molded soft or hard
glass. |
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Refraction |
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The bending of light rays. |
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Refractor |
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A translucent fixture covering, such
as a lens or diffuser that refracts or bends light rays. |
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Resistance |
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A measure of resistance to flow of
current, expressed in ohms. |
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Scotopic Vision |
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Sight involving the eye's rods, which
respond to low levels of lighting, below .034 candela per square meter. |
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SON |
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High Pressure Sodium abbreviation
term. |
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SOX |
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Low Pressure Sodium abbreviation term. |
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Spectral Power Distribution |
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A graph of the radiant power emitted
by a light source as a function of wavelength. SPD's provide a visual
profile of the color characteristics of the light source throughtout
the visible part of the spectrum. |
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Starter |
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A device used in conjunction with
a ballast to start preheat fluorescent lamps. |
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TCLP Test |
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The Toxicity Characteristic Leaching
Procedure (TLCP) test, specified in the Resource Conservation and
Recovery Act (RCRA) of 1990, is used to characterize fluorescent lamp
waste as hazardous or nonhazardous waste. The TCLP test measures the
ability of the mercury in a lamp to leach from a landfill into ground
water under very aggressive and reactive conditions. |
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Total Harmonic Distortion |
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A measure of the distortion of an
electrical wave form. Excessive THD may cause adverse effects to the
electrical system. |
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Trigger Start |
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A circuit used that eliminates the
starter and allows for instant starting of preheat lamps. |
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Troffer |
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A long recessed lighting fixture,
usually installed flush with the ceiling. |
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Ultraviolet |
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Radiant energy in the wavelength
range of about 100 to 380 nanometers (nm). This light is invisible
to the naked eye and is also known as black light. Blacklight ................ 320-400 nm |
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Very High Output (VHO) Lamps |
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Fluorescent lamps designed to be used
with a 1500 milliampere ballast. |
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Visible Spectrum |
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Radiant energy in the wavelength range
of about 380 to 770 nanometers (nm). The light that can be seen by
the naked eye and produces what we also call the "color spectrum". |
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Volt |
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The unit of electromotive force (emf).
The difference in electrical potential that will cause a current of
one ampere to flow through a resistance of one ohm. |
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Voltage Rating |
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The recommended operating voltage
for a lamp. |
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Watt |
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A unit of electrical power. One watt
is equal to one ampere of currrent flowing through one ohm of resistance. |
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Wavelength |
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Distance between two successive points
of a periodic wave; the wavelegth of light are expressed in nanometers. |
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5515 St. Augustine
Road Jacksonville, FL. 32207 PH: 800-413-9847 FAX: 800-385-3149 Copyright 2006, David Tyson, All Rights Reserved. |