Crestron Lighting Software | Appendix D |
DOWNLIGHT: A type of ceiling luminaire, usually fully recessed, where most of the light is directed downward. May feature an open reflector and/or shielding device
E
EFFICACY: A metric used to compare light output to energy consumption. Efficacy is measured in lumens per watt. Efficacy is similar to efficiency, but is expressed in dissimilar units. For example, if a
ELECTROLUMINESCENT: A light source technology used in exit signs that provides uniform brightness, long lamp life (approximately eight years), while consuming very little energy (less than one watt per lamp)
ELECTRONIC BALLAST: A ballast that uses
ELECTRONIC DIMMING BALLAST: A variable output electronic fluorescent ballast
ELECTRONIC
EMI: Abbreviation for electromagnetic interference. EMI is the high frequency interference (electrical noise) caused by electronic components or fluorescent lamps that interferes with the operation of electrical equipment. EMI is measured in
F
FC: (SEE FOOTCANDLE)
FLUORESCENT LAMP: A light source consisting of a tube filled with argon, along with krypton or other inert gas. When electrical current is applied, the resulting arc emits ultraviolet radiation that excites the phosphors inside the lamp wall, causing them to radiate visible light
FOOTCANDLE (FC): The English unit of measurement of the illuminance (or light level) on a surface. One footcandle is equal to one lumen per square foot
FOOTLAMBERT: English unit of luminance. One footlambert is equal to 1/p candelas per square foot.
FORWARD PHASE DIMMING: Rather than attempting to restrict the amplitude of the current flowing through a lamp, as in other forms of dimming, forward phase control works by switching off the beginning part of each cycle of the alternating current supply
G
GLARE: The effect of brightness or differences in brightness within the visual field sufficiently high to cause annoyance, discomfort or loss of visual performance
H
HALOGEN: (SEE TUNGSTEN HALOGEN LAMP)
HARMONIC DISTORTION: A harmonic is a sinusoidal component of a periodic wave having a frequency that is a multiple of the fundamental frequency. Harmonic distortion from lighting equipment can interfere with other appliances and the operation of electric power networks. The total harmonic distortion (THD) is usually expressed as a percentage of the fundamental line current. THD for
HID: Abbreviation for high intensity discharge. Generic term describing mercury vapor, metal halide,
HIGH BAY: Pertains to the type of lighting in an industrial application where the ceiling is 20 feet or higher. Also describes the application itself
HIGH OUTPUT (HO): A lamp or ballast designed to operate at higher currents (800 mA) and produce more light.
HIGH POWER FACTOR: Ballast with a 0.9 or higher rated power factor, which is achieved by using a capacitor.
HIGH PRESSURE SODIUM LAMP: A high intensity discharge (HID) lamp whose light is produced by radiation from sodium vapor (and mercury)
HOT RESTART or HOT RESTRIKE: The phenomenon of
I
IESNA: Abbreviation for Illuminating Engineering Society of North America.
ILLUMINANCE: A photometric term that quantifies light incident on a surface or plane. Illuminance is commonly called light level. It is expressed as lumens per square foot (footcandles), or lumens per square meter (lux)
INDIRECT GLARE: Glare produced from a reflective surface.
INSTANT START: A fluorescent circuit that ignites the lamp instantly with a very high starting voltage from the ballast. Instant start lamps have
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