Light+Vocabulary



("Amps.") A measure of electrical current. In incandescent lamps, the current is related to voltage and power as follows: Watts (power) = Volts x Amps (current). A style of bulb base which uses keyways instead of threads to connect the bulb to the fixture base. The bulb is locked in place by pushing it down and turning it clockwise. A short, thick post with a light at its top, used for grounds and outdoor walkway lighting. A system for measuring the color of the light emitted from a light source--either a primary source like a lamp or a secondary source like an illuminated object. Usually two numbers, x and y coordinates ranging from 0 to 1 specify the chromaticity. Windings of copper or aluminum wire surrounding the steel core in ballast. Also refers to the entire assembly comprising the inductor or transformer. Whether or not the lamp lumens can be varied while maintaining reliability. A continuum of electric and magnetic radiation that can be characterized by wavelength or frequency. Visible light encompasses a small part of the electromagnetic spectrum in the region from about 380 nanometers (violet) to 770 [|nanometers] (red) by wavelength. **A curve depicting the sensitivity of the human eye as a function of wavelength (or color). The peak of human eye sensitivity is in the yellow-green region of the spectrum. The normal curve refers to photopic vision or the response of the cones. (See [|Photopic], [|Scotopic] , [|Fovea, Foveal vision] ) Filaments are designated by a letter combination in which C is a coiled wire filament, CC is a coiled wire that is itself wound into a larger coil, and SR is a straight ribbon filament. Numbers represent the type of filament-support arrangement. **Glare **: direct glare is caused by light coming directly to the eye from a light source. Indirect glare is light reflected from a surface in the direction of the eye. Both can harm vision and cause visual discomfort or disability. Distortion of an AC waveform caused by multiples of the fundamental frequency (harmonics). Odd triplet harmonics (thirds, ninths, etc.) may result in large currents on the neutral line in a four-wire Wye three-phase system. An electronic device providing a high voltage pulse to initiate an electrical discharge. Typically, the ignitor is paired with or is a part of the ballast A plot with lines connecting points of equal luminous intensity around a source. Layers of steel, making up the "core" that is surrounded by the coils in a core & coil ballast. A transparent or semi-transparent element which controls the distribution of light by redirecting individual rays. Luminaires often have lenses in addition to reflectors. A nationally accepted electrical installation code to reduce the risk of fire, developed by the National Fire Protection Association. Ballasts with power factor less than .90 and do not incorporate any means of Power Factor Correction. Lamps that are approved for burning in open fixtures (as opposed to enclosed fixtures which have an acrylic lens or plate glass enclosure). An inorganic chemical compound processed into a powder and deposited on the inner glass surface of fluorescent tubes and some mercury and metal-halide lamp bulbs. Phosphors are designed to absorb short wavelength ultraviolet radiation and to transform and emit it as visible light Material used to completely surround and cover components of some magnetic and electronic ballasts. Potting compound fulfills functions of protecting components, dampening sound, and dissipating heat. A name for fused silica or melted sand from which many high-temperature containers are fashioned in the lighting industry. Quartz looks like glass but can withstand the high temperatures needed to contain high intensity arc discharges. Vision where the rods of the retina are exclusively responsible for seeing, typically like the light levels in the countryside on a moonless, starlit night A common way of referring to high efficiency GE T8 family of lamps that perform better than standard T8 lamps. Also refers to the [|system]. **A measure of "electrical pressure" between two points. The higher the voltage, the more current will be pushed through a resistor connected across the points. The volt specification of an incandescent lamp is the electrical "pressure" required to drive it at its designed point. The "voltage" of a ballast (e.g. 277 V) refers to the line voltage it must be connected to. **Work Plane** Plane at which work is done and at which illumination is specified and measured; unless otherwise indicated, it is assumed to be a horizontal plane 30 inches above the floor (table-top height) having the same area as the floor.
 * Amperes**
 * Bayonet**
 * Bollard**
 * Chandelier **: a chandelier is often the focal point of the dining room. As such it should be hung about 30 inches above the tabletop and should be at least 6 inches narrower than the table on each side.
 * Chromaticity Coordinates**
 * Coil**
 * Dimmable**
 * Electromagnetic Spectrum**
 * Eye Sensitivity
 * Filament Design**
 * Harmonic Distortion**
 * Ignitor**
 * Isocandela Plot**
 * Laminations**
 * Lens**
 * National Electric Code (NEC)**
 * Normal Power Factor**
 * Open Fixture Rated**
 * Phosphor**
 * Potting**
 * Quartz**
 * Scotopic**
 * Ultra**
 * Volt