Definition of Terms Flashcards
The standard unit of measurement for electric current that is equal to one coulomb per second. It defines the quantity of electrons moving past a given point in a circuit during a specific period.
Amphere
What is ANSI?
American National Standards Institute
A tube enclosed by the outer glass envelope of a HID lamp and made of clear quartz or ceramic that contains the arc stream.
Arch Tube
What is ASHRAE?
American Society of Heating, Refrigerating and Air-Conditioning Engineers
A single opaque or translucent element used to control light distribution at certain angles
baffle
A device used to operate fluorescent and HID lamps. It provides the necessary starting voltage, while limiting and regulating the lamp current during operation
Ballast
Undesirable condition under which the ballast turns lamps on and off(cycles) due to the overheating of the thermal switch inside the ballast. This may be due to incorrect lamps, improper voltage being supplied, high ambient temperature around the fixture, or the early stage of ballast failure.
Ballast Cycling
the ballast factor divided by the input power of the ballast.
BALLAST EFFICIENCY FACTOR
represents the percentage of the rated lamp lumens that will be produced by the combination
Ballast factor
Unit of luminous intensity, describing the intensity of a light source in a specific direction
Candela
curve, often on polar coordinates, illustrating the variation of luminous intensity of a lamp or luminaire in a plane through the light center
Candela Distribution
A measure of luminous intensity of a light source in a specific direction, measured in candelas
Candle Power
What is CBM?
Certified Ballast Manufacturers Association.
What us CEC?
California Energy Commission
The ratio of lumens from a luminaire received on the work plane to the lumens produced by the lamps alone.
Coefficient of Utilization
A scale of the effect of a light source on the color appearance of an object compared to its color appearance under a reference light source.
Color Rendering Index
is a specification of the color appearance of a light source, relating the color to a reference source heated to a particular temperature, measured by the thermal unit Kelvin. The measurement can also be described as the “warmth” or “coolness” of a light source. Generally, sources below 3200K are considered “warm;” while those above 4000K are considered “cool” sources
Color Temperature
A small fluorescent lamp that is often used as an alternative to incandescent lighting.
Compact Fluorescent
A premium type of HID ballast in which the primary and secondary coils are isolated.
Constant Wattage ballast
A popular type of HID ballast in which the primary and secondary coils are electrically connected. Considered an appropriate balance between cost and performance.
Constant wattage autotransformer ballast
The relationship between the luminance of an object and its background
Contrast
The angle from a fixture’s vertical axis at which a reflector, louver, or other shielding device cuts off direct visibility of a lamp. It is the complementary angle of the shielding angle.
Cut-off angle
A dimming system controlled by a photocell that reduces the output of the lamps when daylight is present. As daylight levels increase, lamp intensity decreases. An energy-saving technique used in areas with significant daylight contribution.
Daylight Compensation
Term describing dispersed light distribution. Refers to the scattering or softening of light.
Diffuse
A translucent piece of glass or plastic sheet that shields the light source in a fixture.
Diffuser
Glare produced by a direct view of light sources
Direct Glare
A type of ceiling luminaire, usually fully recessed, where most of the light is directed downward
Down light
A metric used to compare light output to energy consumption. measured in lumens per watt.
Efficiency
