Alternating Current
(AC) - current that
changes its direction of flow through a conductor, going first one way, then the
other. The usual rate used is 60 alternations (60 times each way) per second.
Ampere (AMP)
-the unit for measuring rate of flow of electrical current.
ANSI
- the American National Standards Institute, Inc. is the coordinator of
standards, including lighting standards, on a national level.
Arc Lamp -a
discharge lamp in which the light is emitted by an arc discharge or by its
electrodes. (HID)
Arc Tube -a
tube within the outer glass envelope of an HID lamp and made of clear quartz or
ceramic that contains the arc stream.
Argon
- an inert (will not unite with any other elements to form chemical compounds)
gas used in incandescent and fluorescent lamps. In incandescent lamps it helps
to retard evaporation of tungsten filament.
Average Rated Life
- how long it takes to burn out a lamp. For example, you can expect a 60 watt
lamp to burn for about 10,000 user hours, based on continuous testing of lamps
in laboratories. The 10,000 user hour rating is the point in time when 50% of
the tested samples have burned out and 50% still shine.
Ballast
- a device used with an electric discharge lamp to obtain and regulate the
necessary electric current.
Base
- the portion of the lamp that provides a means of connecting the lamp to the
socket.
Beam Candlepower
- a measurement of beam intensity from reflector lamps as opposed to overall
lumens of non-reflector lamps.
Beam Spread
- the angle of light distribution from a specific light source on one plane in
which the candlepower is 50% of the maximum.
Blackbody
- a theoretical body used by the lighting industry as a form of establishing the
“color” and spectral qualities of lamps. A perfect blackbody, when its
temperature has risen to 3500° K would give out light of a certain color; at
4500° K, it would give a whiter color, and at a 5500° K, a still whiter color.
Brightness
- the intensity of the sensations, which results from viewing a surface or space
which directs light into the eyes.
Bulb Darkening
- the darkening of an incandescent lamp caused by small particles of tungsten
that evaporate from the filament and deposit on the lamp as the filament burns.
Burn Cycle
- the burning hours per start of a lighting system. Burn cycle affects the
average rated lamp life. Fluorescent lamp life is rated at 3 hours per burn
cycle. For fluorescent systems that have longer burn cycles, the lamps will have
longer than average rated life; for fluorescent systems that have shorter burn
cycles, the lamps will have shorter than average rated life.
Candela
- the international basic physical quantity of all measurements of light. All
other units are derived from it. Its value is determined by the light emitted by
a laboratory device operating at a specific temperature.
Candlepower
- a measurement of light intensity.
Cathode
- an electrode that emits electrons. The fluorescent lamp cathode emits or
discharges electrons to the cathode at the opposite end of the lamp.
Chromaticity (of a
color) - the
dominant or complementary wavelength and purity aspects of the color taken
together (of a light source) - the whiteness of a light source expressed in
degrees Kelvin (K).
Color Rendering
Index (CRI) -a
rating method by which any fluorescent lamp is evaluated according to its
variance from natural outdoor light, which has a CRI of 100. It is sometimes
referred to as Chromatic Index.
Color Spectrum
- all the radiant energy wave lengths that make human sight possible. The
visible wavelengths include all colors and are measured in nanometers.
Compact Fluorescent
Lamp (CFL) - the
generic name for a family of single-ended fluorescent lamps of folded or bridged
tube design with high color rendering (CRI>80) and long life (up to 10,000
user hours)
Correlated Color
Temperature (CCT) -
the absolute temperature, measured in degrees Kelvin, of a blackbody radiator
whose chromaticity most nearly resembles that of the light source.
Canadian Standards
Association (CSA) -
an organization that writes standards and tests lighting equipment for
performance as well as electrical and fire safety.
Direct Current
- electric current without alterations. DC does not affect incandescent
adversely. High voltage Mercury Vapor can be used if DC is used with polarity
switches.
Efficacy
- a measure used to compare light output to energy consumption. Efficacy is
measured in lumens per watt. For example, if a 100 watt light source produces
1750 lumens, then the efficacy of the light source is 17.5 lumens per watt.
Electric Discharge
Lamps - a lamp in
which light is produced by the passage of an electric current through a vapor or
gas.
Electrode
- a coasted metal element which facilitates the emission of electrons to form an
arc within a fluorescent lamp.
Emission Coating
- an oxide coating deposited on a cathode that emits electrons when heated.
Energy Policy Act (EPACT)
- energy legislation passed by the U.S. Congress in 1992. The lighting portion
includes lamp labeling and minimum energy efficacy (lumens/watt) requirements
for many incandescent and fluorescent lamp types.
Energy Star
- Energy Star was introduced by the U.S. Environmental Protection Agency in 1992
as a voluntary labeling program designed to identify and promote
energy-efficient products in order to reduce carbon dioxide emissions. The EPA
partnered with the U.S. Department of Energy in 1996 to promote the Energy Star
label.
Filament -
a tungsten wire that lights up when an electric current runs through it. The
light source in an incandescent lamp.
Fluorescent
- light resulting from the action of ultraviolet or other forms of energy on
phosphors. Fluorescence occurs only while energy is being absorbed by the
fluorescing material.
Fluorescent Lamps -
a low-pressure mercury electric-discharge lamp in which a phosphor transforms
some of the UV energy generated by the discharge into light.
Foot Candle
- one lumen uniformly distributed over one square foot of surface. One lumen
falling on one square foot of surface produces illumination of one foot candle.
Halogen
- a gas-filled tungsten incandescent lamp, containing a certain proportion of
halogens in an inert gas which is under pressure.
High Bay - high
ceiling, usually in an industrial plant. Because of height, it may be hard to
reach for lamp changes without special ladders or scaffolding. Usually above 20
ft.
High-Intensity
Discharge Lamp (HID)
- a general term for mercury vapor, metal halide and high-pressure sodium lamps.
HID lamps contain compact arc tubes, which enclose various gases and metal salts
operating at relatively high pressures and temperatures.
High Output (HO)
- a fluorescent lamp designed for use with an 800 milliampere ballast. Will
usually operate at low temperatures near zero and still produce high light
output.
High Voltage
- voltage of 208 and higher.
High Power Factor (HPF)
- the term applied to lighting ballasts and other AC electrical devices that
measure 0.9 (90%) or higher.
High-Pressure
Sodium Lamp (HPS) -
HPS lamps are high intensity discharge lamps, which produce light by an
electrical discharge through sodium vapor operating at relatively high pressures
and temperatures.
Incandescence
- light emission by a heated filament or coil.
Incandescent Lamp
- a lamp in which light is produced by the passage of an electric current
through a wire.
Infra-red
- radiant
energy heat with wavelengths that are longer than the wavelengths of the visible
spectrum.
Instant Start
- refers to fluorescent lamps that start instantly, without pre-heating of
cathodes, and without the need of starters.
Kelvin Temperature
Scale - absolute
temperature scale, 0° Kelvin is equal to -273.16° Centigrade. Term used to
indicate the comparative color appearance of a light source compared to a
theoretical black body.
Kilowatt - one thousand watts.
Kilowatt Hour - one thousand watts of electric energy consumed in one hour.
Example: One 1,000 watt lamp or ten 100 watt lamps burning for one hour.
Krypton - a very heavy inert gas, which permits the filament to glow hotter and
brighter while, still providing long life.
Lamp - generic term for man-made light source (light bulb).
Lumen - the SI unit luminous flux. Lumens represent the time rate of
transferring luminous energy; quantity of light. One lumen is the light flux
falling on a surface of one square foot, every part of which is one foot from a
point source having a luminous intensity of one candela in all direction.
Lumen Maintenance Curve - this curve shows the loss of light output against
life.
Mercury Vapor Lamp
-a
discharge lamp in which the light is emitted by an arc discharge or by its
electrodes. (HID)
Metal Halide Lamp - an
electric discharge lamp in which the major portion of the radiation is produced
by the excitation of mercury atoms.
M.O.L. -maximum overall length of a lamp.
Nominal Length - overall length of a fluorescent lamp installed (including
sockets).
North Light - scattered (not direct sunlight) light from the north sky at noon.
About 7500° Kelvin.
Preheat - a fluorescent system, which requires starters. This system requires
several seconds of heating from the time the circuit is turned on to the time
the lamp produces light.
Rapid Start - a fluorescent system which does not require starters and takes 1
or 2 seconds to light.
Spectral - color spectrum rating.
Spectral Distribution Charts - the term “spectral distribution” refers to
the various wavelengths (colors) of light emitted by a lamp, and the intensity
of power of the various wavelengths.
Starter - a device used in conjunction with a ballast for the purpose of
starting an electric discharge lamp.
Total Harmonic Distortion (THD) - a measure of the degree, to which the input
current is distorted from a sine wave, measured as a percentage. THD is usually
expressed as a percentage of the fundamental frequency line current. THD for
4-foot electromagnetic fluorescent ballasts range from 20% to 40%. For compact
fluorescent ballasts, THD levels greater that 50% are common.
Underwriters Laboratories (UL) - a private organization which tests and lists
electrical and fire safety according to recognized UL and other standards.
Ultra-High Output (UHO®) - a fluorescent lamp which operates with 1500
milliampere ballast. It is used whenever higher footcandle levels are needed,
using fewer lamps. Also called VHO - Very High Output or SHO - Super High
Output.
Ultraviolet Radiation (UV) - for practical purposes, any radiant energy within
the wavelength range of 10 to 380 nanometers. It is invisible radiation that is
shorter in wavelength than visible violet light (literally beyond the violet
light).
Visible Spectrum - the complete range of energy wavelengths that activate human
eyesight.
Volt - the standard unit of measurement for electrical potential.
Voltage - the difference in electrical potential between two points of an
electrical circuit. The voltage of a circuit is the electrical pressure it
gives. In an incandescent lamp, “voltage” designates the supply voltage to
which the lamp should be connected. In other lamp types, it may refer to
“operating voltage” of a lighted discharge lamp.
Watt - a unit of power consumption.
Keywords:
Duro-Test, Duro-Test Lighting, Durotest, Vita-Lite, Vitalite, Lighting Glossary
of Terms, Alternating Current (AC), Ampere (AMP), ANSI - the American National
Standards Institute, Inc., Arc Lamp, Argon, Ballast, Beam Candlepower, Beam
Spread, Blackbody, Burn Cycle, Candela, Candlepower, Cathode, Chromaticity,
Color Rendering Index (CRI), Color Spectrum, Compact Fluorescent Lamp (CFL),
Correlated Color Temperature (CCT), Canadian Standards Association (CSA),
Efficacy, Electric Discharge Lamps, Electrode, Emission Coating , Energy Policy
Act (EPACT), Energy Star, Filament, Fluorescent, Fluorescent Lamps, Foot Candle,
Footcandle, Halogen, High Bay, High-Intensity Discharge Lamp (HID), High Output
(HO), High Power Factor (HPF), High-Pressure Sodium Lamp (HPS), Incandescence,
Incandescence Lamps, Infra-red , Infrared, Kelvin Temperature Scale, Krypton,
Lumen, Lumen Maintenance Curve, Metal Halide Lamp, North Light, Spectral
Distribution Charts, Total Harmonic Distortion (THD), Underwriters Laboratories
(UL), Ultra-High Output (UHO®), VHO Very High Output, SHO Super High Output,
Ultraviolet Radiation (UV), Visible Spectrum, Full Spectrum Lighting,
Environmental Protection Agency EPA, Light Bulbs
