Light_Vocabulary

Genuine alabaster is a very fine variety of crystalline gypsum (hydrous calcium sulfate) found in nature. It is translucent and its color is often white, pearly, or silky colorless but it, more often than not, has subtle reddish-brown bands of iron oxide running through it. It is often used for decorative objects such as light fixtures or figurines.
 * A **
 * Alabaster **
 * Arc **

Intense luminous discharge formed by the passage of electric current in a gaseous medium across a space between electrodes.
 * Atmosphere **

This field designates the type of gas or vacuum filling a volume or chamber of the lamp. This chamber might contain a filament or it might refer to the bulb which contains the arc tube.


 * B **
 * Ballast **

=
An auxiliary piece of equipment required to start and to properly control the flow of current to gas discharge light sources such as fluorescent and  high intensity descharge (HID)  lamps. Typically, magnetic ballasts (also called electromagnetic ballasts) contain copper windings on an iron core while electronic ballasts are smaller and more efficient and contain electronic components =====
 * Base or Socket **

The socket is the receptacle connected to the electrical supply; the base is the end of the lamp that fits into the socket. There are many types of bases used in lamps, screw bases being the most common for incandescent and HID lamps, while bipin bases are common for linear fluorescent lamps
 * <span style="color: #666666; font-family: Arial,sans-serif; font-size: 12pt;">Beam Angle **

<span style="color: #666666; font-family: Arial,sans-serif; font-size: 12pt;">The angular dimension of the cone of light from reflectorized lamps (such as <span style="font-family: Arial,sans-serif; font-size: 12pt;">R <span style="color: #666666; font-family: Arial,sans-serif; font-size: 12pt;"> and PAR types) encompassing the central part of the beam out to the angle where the intensity is 50% of maximum. The beam angle sometimes called "beam spread" is often part of the ordering code for the reflectorized lamps. Example: The 50PAR30/HIR/NFL25 is a 50 watt PAR30 narrow flood lamp with a beam angle of 25 degrees
 * <span style="color: #404040; font-family: Arial,sans-serif;">Bayonet Base **<span style="color: #404040; font-family: Arial,sans-serif;">: a type of lamp base with pins that serve to lock the lamp into slots in the lamp socket of a luminaire. The bayonet base got its name from the method used by soldiers to mount bayonets on their rifles. **<span style="color: #666666; font-family: Arial,sans-serif;">Bulb Material or Coating **

<span style="color: #666666; font-family: Arial,sans-serif;">The type of glass (or quartz) used in the glass envelope surrounding the light source. The material can also have coatings applied to achieve particular performances.


 * <span style="color: #666666; font-family: Arial,sans-serif;">C **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Cathode **

<span style="color: #666666; font-family: Arial,sans-serif;">Metal filaments that emit electrons in a fluorescent lamp. Negatively charged free electrons emitted by the cathode are attracted to the positive electrode (anode), creating an electric current between the electrodes.
 * <span style="color: #666666; font-family: Arial,sans-serif;">ChromaFit **

<span style="color: #666666; font-family: Arial,sans-serif;">A GE brand name for metal halide lamps designed to operate on HPS ballasts, allowing a user to switch from the yellowish color of HPS to the white color of metal halide without changing ballasts. These products are available in both quartz metal halide and ceramic metal halide (CMH) versions
 * <span style="color: #666666; font-family: Arial,sans-serif;">Class P Thermal Protector **

<span style="color: #666666; font-family: Arial,sans-serif;">A switching device sensitive to current and heat that automatically disconnects ballast if the temperature exceeds UL temperature limitations.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Compact Fluorescent Lamp (CFL) **

<span style="color: #666666; font-family: Arial,sans-serif;">The general term applied to fluorescent lamps that are single-ended and that have smaller diameter tubes that are bent to form a compact shape. Some CFLs have integral ballasts and medium or candelabra screw bases for easy replacement of incandescent lamps.


 * <span style="color: #666666; font-family: Arial,sans-serif;">D **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Dichroic Reflector (or Filter) **

<span style="color: #666666; font-family: Arial,sans-serif;">A reflector (or filter) that reflects one region of the spectrum while allowing the other region(s) to pass through. A reflector lamp with a dichroic reflector will have a "cool beam" i.e. most of the heat has been removed from the beam by allowing it to pass through the reflector while the light has been reflected.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Distance Between Leg Centers **

<span style="color: #666666; font-family: Arial,sans-serif;">For U-shaped Fluorescent lamps, this measurement is the average distance between the centers of each leg.
 * <span style="color: #404040; font-family: Arial,sans-serif;">Dimmer **<span style="color: #404040; font-family: Arial,sans-serif;">: a device in an electrical circuit used for varying the brightness of lamps in a lighting installation. Dimming controls are ideal for almost any type of room because they can change the amount of lighting to suit each mood or activity and they can help you look good. The use of dimmers with incandescent, xenon, and halogen light sources also **//increases//** <span class="apple-converted-space" style="color: #404040; font-family: Arial,sans-serif;"> the life of the lamps and <span style="color: #404040; font-family: Arial,sans-serif;">**//decreases//** <span class="apple-converted-space" style="color: #404040; font-family: Arial,sans-serif;"> the use of electrical energy. (Please see the Table below.)


 * <span style="color: #404040; font-family: Arial,sans-serif;">E **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Electrical Testing Laboratory (ETL) **

<span style="color: #666666; font-family: Arial,sans-serif;">Independent testing laboratory that performs ballast tests and certifies accuracy of performance data.
 * <span style="color: #404040; font-family: Arial,sans-serif;">ER Lamp **<span style="color: #404040; font-family: Arial,sans-serif;">: a type of incandescent reflector lamp with the reflector shaped like an ellipsoid (a 3-dimensional ellipse) with the lamp's filament located at one of the two foci of the ellipsoid so that the light is focused directly in front of the lamp at the second foci


 * <span style="color: #404040; font-family: Arial,sans-serif;">F **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Footlambert **

<span style="color: #666666; font-family: Arial,sans-serif;">An obsolete term referring to a luminance of 1/? candelas per square foot.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Full Spectrum Lighting **

<span style="color: #666666; font-family: Arial,sans-serif;">A marketing term, typically associated with light sources that are similar to some forms of natural daylight (5000K and above, 90+ CRI), but sometimes more broadly used for lamps that have a smooth and continuous color spectrum.


 * <span style="color: #666666; font-family: Arial,sans-serif;">G **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Glare **

<span style="color: #666666; font-family: Arial,sans-serif;">Visual discomfort caused by excessive brightness is called discomfort glare. If task performance is affected it is called disability glare. <span style="background-color: white; color: #666666; font-family: Arial,sans-serif;">Glare can be direct glare or indirect (reflected) glare <span style="color: #666666; font-family: Arial,sans-serif;">.


 * <span style="color: #666666; font-family: Arial,sans-serif;">H **
 * <span style="color: #404040; font-family: Arial,sans-serif;">Halogen Lamp **<span style="color: #404040; font-family: Arial,sans-serif;">: a type of incandescent lamp (light bulb) that contains halogen gases (such as iodine, chlorine, bromine, and fluorine), which slow the evaporation of the tungsten filament. Also, sometimes called a tungsten halogen lamp or a quartz lamp. The glass envelope that surrounds the filament of a halogen lamp should **//not//** <span class="apple-converted-space" style="color: #404040; font-family: Arial,sans-serif;"> be touched with bare hands. The natural oil from human hands will only help to shorten the life of halogen lamps. If you should accidentally touch the glass bulb, you should thoroughly remove your fingerprints with methylated spirit (denatured alcohol).
 * <span style="color: #666666; font-family: Arial,sans-serif;">Harmonic Distortion **

<span style="color: #666666; font-family: Arial,sans-serif;">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.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Hot Restart Time **

<span style="color: #666666; font-family: Arial,sans-serif;">Time it takes for a High Intensity Discharge lamp to reach 90% of light output after going from on to off to on.


 * <span style="color: #666666; font-family: Arial,sans-serif;">I **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Ignitor **

<span style="color: #666666; font-family: Arial,sans-serif;">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
 * <span style="color: #666666; font-family: Arial,sans-serif;">Infrared Radiation **

<span style="color: #666666; font-family: Arial,sans-serif;">Electromagnetic energy radiated in the wavelength range of about 770 to 1,000,000 nanometers<span style="color: #666666; font-family: Arial,sans-serif;">. Energy in this range cannot be seen by the human eye, but can be sensed as heat by the skin.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Isocandela Plot **

<span style="color: #666666; font-family: Arial,sans-serif;"> A plot with lines connecting points of equal luminous intensity around a source.
 * <span style="color: #666666; font-family: Arial,sans-serif;">K **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Kilowatt Hour (kWh) **

<span style="color: #666666; font-family: Arial,sans-serif;">The standard measure of electrical energy and the typical billing unit used by electrical utilities for electricity use. A 100-watt lamp operated for 10 hours consumes 1000 watt-hours (100 x 10) or one kilowatt-hour. If the utility charges $.10/kWh, then the electricity cost for the 10 hours of operation would be 10 cents (1 x $.10)


 * <span style="color: #666666; font-family: Arial,sans-serif;">L **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Light Emitting Diode (LED) **

<span style="color: #666666; font-family: Arial,sans-serif;">A solid that directly converts electrical impulses into light. Some LED's today incorporate fluorescent materials to change the color characteristics of the emitted light.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Light Trespass (Spill Light) **

<span style="color: #666666; font-family: Arial,sans-serif;">Light that is not aimed properly or shielded effectively can spill out at into areas that don't want it: it can be directed towards drivers, pedestrians or neighbors. It is distracting and annoying and can sometimes be disabling. **Lux (lx)**

<span style="color: #666666; font-family: Arial,sans-serif;">A unit of illuminance or light falling onto a surface. One lux is equal to one lumen per square meter. <span style="background-color: white; color: #666666; font-family: Arial,sans-serif;">Ten lux approximately equals one footcandle

<span style="color: #666666; font-family: Arial,sans-serif;">The end-to-end measurement of a lamp, expressed in inches or millimeters.
 * <span style="color: #666666; font-family: Arial,sans-serif;">M **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Maximum Overall Length (M.O.L.) **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Metal Halide Lamp **

<span style="color: #666666; font-family: Arial,sans-serif;"> A high intensity discharge light source in which the light is produced by the radiation from mercury, plus halides of metals such as sodium, scandium, indium and dysprosium. Some lamp types may also utilize phosphor coatings. GE trade names include: Multi-Vapor®, ConstantColor® CMH®, PulseArc®, Staybright®, Watt-Miser®, ChromaFit and Arcstream®.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Mesopic **

<span style="color: #666666; font-family: Arial,sans-serif;"> Typically referring to nighttime outdoor lighting conditions, the region between PHOTOPIC and SCOTOPIC vision


 * <span style="color: #666666; font-family: Arial,sans-serif;">N **
 * <span style="color: #666666; font-family: Arial,sans-serif;">National Stock Number **

<span style="color: #666666; font-family: Arial,sans-serif;"> The standardized part number used by the US Government for procurement.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Nanometer **

<span style="color: #666666; font-family: Arial,sans-serif;"> A unit of wavelength equal to one billion


 * <span style="color: #666666; font-family: Arial,sans-serif;">O **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Open Fixture Rated **

<span style="color: #666666; font-family: Arial,sans-serif;"> Lamps that are approved for burning in open fixtures (as opposed to enclosed fixtures which have an acrylic lens or plate glass enclosure).
 * <span style="color: #666666; font-family: Arial,sans-serif;">Operating Position or Burn Position **

<span style="color: #666666; font-family: Arial,sans-serif;"> Mercury and High Pressure Sodium lamps may be operated in any burn position and will still maintain their rated performance specifications. Metal Halide and Low Pressure Sodium lamps, however, are optimized for performance in specific burn positions, or may be restricted to certain burn positions for safety reasons.


 * <span style="color: #666666; font-family: Arial,sans-serif;">P **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Preheat Lamp **

<span style="color: #666666; font-family: Arial,sans-serif;"> A fluorescent lamp in which the filament must be heated by use of a starter before the arc is created. These lamps are typically operated with electromagnetic ballasts.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Product Code **

<span style="color: #666666; font-family: Arial,sans-serif;"> It is important to use this five-digit code when ordering to ensure that you receive the exact product you require.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Programmed Rapid Start **

<span style="color: #666666; font-family: Arial,sans-serif;"> Lamp starting method which preheats the lamp filaments while not allowing the lamp to ignite and then applies the open circuit voltage (OCV) to start the lamp. The user may experience a half- to one-second delay after turning on the lamps while the pre-heating takes place. This type of starting circuit keeps lamp end blackening to a minimum and improves lamp life performance, especially in applications where the lamps are frequently switched on and off.


 * <span style="color: #666666; font-family: Arial,sans-serif;">Q **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Quad **

<span style="color: #666666; font-family: Arial,sans-serif;"> Generally refers to a compact fluorescent lamp containing 4 U-shaped tubes, i.e. Quad Biax®, as opposed to Triple Biax® (3 tubes) and Double Biax® (2-tubes).
 * <span style="color: #666666; font-family: Arial,sans-serif;">Quartz **

<span style="color: #666666; font-family: Arial,sans-serif;"> 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.
 * <span style="color: #666666; font-family: Arial,sans-serif;">R **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Rated Lamp Life **

<span style="color: #666666; font-family: Arial,sans-serif;"> For most lamp types, rated lamp life is the length of time of a statistically large sample between first use and the point when 50% of the lamps have died. It is possible to define "useful life" of a lamp based on practical considerations involving lumen depreciation and color shift
 * <span style="color: #666666; font-family: Arial,sans-serif;">Reflectance **

<span style="color: #666666; font-family: Arial,sans-serif;"> The ratio of light reflected from a surface to that incident upon it.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Reveal® **

<span style="color: #666666; font-family: Arial,sans-serif;"> GE's product family of incandescent lamps with the element Neodymium added to the glass bulb. Neodymium filters out much of the yellow light produced by ordinary lamps. Less yellow means whites look whiter and colors appear more vibrant in spaces lighted with Reveal lamps.


 * <span style="color: #666666; font-family: Arial,sans-serif;">S **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Spectral Power Distribution (SPD) **

<span style="color: #666666; font-family: Arial,sans-serif;"> A graph of the radiant power emitted by a light source as a function of wavelength. SPDs provide a visual profile or "finger print" of the color characteristics of the source throughout the visible part of the spectrum.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Starting Temperature (Minimum) **

<span style="color: #666666; font-family: Arial,sans-serif;"> The minimum ambient temperature at which the lamp will start reliably.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Sunburn **

<span style="color: #666666; font-family: Arial,sans-serif;"> Skin reddening and inflammation caused by overexposure to sources containing UV-B and/or UV-C.
 * <span style="color: #666666; font-family: Arial,sans-serif;">System **

<span style="color: #666666; font-family: Arial,sans-serif;"> A term referring to the lamp and ballast combination, and sometimes to the entire lighting delivery system including the fixture, the optics, the particular layout and the lighting controls.


 * <span style="color: #666666; font-family: Arial,sans-serif;">T **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Task Lighting **

<span style="color: #666666; font-family: Arial,sans-serif;"> Supplemental lighting provided to assist in performing a localized task, e.g. a table lamp for reading or an inspection lamp for fabric inspection.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Transients **

<span style="color: #666666; font-family: Arial,sans-serif;"> High voltage surges through an electrical system caused by lightning strikes to nearby transformers, overhead lines or the ground. May also be caused by switching of motors or compressors, as well as by short circuits or utility system switching. Can lead to premature ballast failure.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Troffer **

<span style="color: #666666; font-family: Arial,sans-serif;"> A long, recessed lighting unit, usually installed in an opening in the ceiling.


 * <span style="color: #666666; font-family: Arial,sans-serif;">U **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Uniform Code Council (UCC) **

<span style="color: #666666; font-family: Arial,sans-serif;"> The 12 digit case code derived from the last 12 digits of the 14 digit SCC code on GE's case content label.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Underwriters' Laboratories (UL) **

<span style="color: #666666; font-family: Arial,sans-serif;"> A private organization which tests and lists electrical (and other) equipment for electrical and fire safety according to recognized UL and other standards. A UL listing is not an indication of overall performance. Lamps are not UL listed except for compact fluorescent lamp assemblies - those with screw bases and built-in ballasts.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Uniform Product Code (UPC) **

<span style="color: #666666; font-family: Arial,sans-serif;">The 12 digit code on the saleable unit that is used for scanning at the register.


 * <span style="color: #666666; font-family: Arial,sans-serif;">V **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Veiling Reflection **

<span style="color: #666666; font-family: Arial,sans-serif;"> Effective reduction in contrast between task and its background caused by the reflection of light rays; sometimes called "reflected glare." You might have dealt with veiling reflections when you have to tilt a shiny magazine to avoid glare so as to read it, or struggled with reading a computer monitor because of the reflection of a window or a light fixture
 * <span style="color: #666666; font-family: Arial,sans-serif;">Visual Comfort Probability (VCP) **

<span style="color: #666666; font-family: Arial,sans-serif;"> For a given lighting scheme, VCP is a ratio expressed as a percent of people who, when viewing from a specific location and in a specified direction, find the system acceptable in terms of glare.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Volt **

<span style="color: #666666; font-family: Arial,sans-serif;"> 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.


 * <span style="color: #666666; font-family: Arial,sans-serif;">W **
 * <span style="color: #666666; font-family: Arial,sans-serif;">Work Plane **

<span style="color: #666666; font-family: Arial,sans-serif;"> 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.
 * <span style="color: #666666; font-family: Arial,sans-serif;">Working Distance (Typical) **

<span style="color: #666666; font-family: Arial,sans-serif;"> For Multi-Mirror® and other reflector Quartzline® lamps and MARC™ Projection lamps, the Working Distance shown is the distance from the front surface of the reflector rim to the film plane, in the optical system for which the lamp was first designed. In most cases, it provides a uniform plane of light for the intended aperture.