A Glossary of Lighting Terms
ACSee alternating current ADEX Awards. American National Standards Institute 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. Some light fixtures use faux alabaster, which is usually man-made glass. Both genuine and faux alabaster can be very attractive. The faux alabaster is generally much less expensive while real alabaster can lose some of its coloration over time. Real alabaster is expensive simply because quarrying it is costly and there is huge amount of waste when it is shaped, finished, and polished. Genuine alabaster is a minimum of 3/8in thick and weighs at least twice as much as imitations and has translucent and dark bands that are completely random in shape, size, and location. Since alabaster is a soft, porous stone it should be treated gently and never cleaned with detergents or abrasives. Instead, wipe alabaster with a slightly damp (not wet), soft cloth. Furthermore, heating alabaster for long periods of time with a high-wattage light bulb may drive out the residual water in the alabaster and turn it completely white. incandescent light bulb that is generally used in most indoor residential lighting applications. By January 1, 2014 the most common standard screw-base incandescent household (A-line) light bulbs will be phased out in the U.S. Clear, frosted, soft white, and daylight light bulbs will be phased out but specialty colors and shapes will not be. The new standards for these light bulbs are technology neutral so any technology that can meet the new energy-efficiency standards can be used - including fluorescent, halogen IR, high-efficiency incandescent, LEDs, and any technologies still to be developed. mercury which is an upgrade from traditional liquid mercury. Since it gives better mercury vapor control in the glass envelope the lamps that use amalgam perform better over a wider variety of temperatures and operating positions. General lighting that usually lights up an entire room or space. ballasts, lamps, and light fixtures (see www.ansi.org). ampere coulomb of electric charge passing a given point in one second. Amperes are sometimes abbreviated as "amps" or simply "A" and are often represented in electrical formulae by the letter, "I", as in V = I x R (volts = amperes x ohms). This unit is named after Andrè-Marie Ampère, a French physicist, who lived during 1775-1836 and is considered to be the "father of electrodynamics". floodlights. incandescent and fluorescent lamps. In incandescent lamps argon retards the evaporation of the filament and, thereby, lengthens the average rated life of the lamp.
Return to Top of Glossaryballast factor opaque, backlighting can cause the edges to "glow". With translucent objects (such as stained glass), backlighting illuminates the object by passing light through it. Backlighting is commonly used to accent artwork, photos, advertisements, or signage. fluorescent and HID lamps to supply sufficient voltage to start and operate the lamp but then limit the current during operation. lumen output for a lamp using ballast to the lumen output for a lamp-ballast system under test conditions established by the American National Standards Institute (ANSI). The higher the ballast factor, generally the more wattage being used by the light fixture. luminaire, such as a track fixture or a theatrical spotlight, which are used to shape and focus the light on a designated area, such as a framed work of art or a stage scene Beam Spread LEDs into a variety of groups based on certain performance characteristics such as color temperature and lumen output. LED manufacturers use binning to manage the slight variations that arise in LEDs during the manufacturing process. luminaire that is a short (usually about 2-4 feet in height) but very sturdy vertical post with the light source located at or near the top. Bollards are typically used to light walkways in commercial settings.
Return to Top of Glossarycenter beam candle power Certified Ballast Manufacturers Association cold cathode fluorescent lamp color temperature Candela compact fluorescent lamp Commission on Illumination color quality scale color rendering index Canadian Standards Association low voltage lighting system where the mechanism holding the light fixtures and conducting electricity to those fixtures is a pair of taut parallel metal cables. UL and ETL in the USA, the CSA is a not-for-profit membership-based association serving business, industry, government, and consumers in Canada and the global marketplace. It is an organization that works in Canada and around the world to develop safety standards that address real needs, such as enhancing public safety and health, advancing the quality of life, and helping to preserve the environment. (see www.csagroup.org/codes-standards/). light source in a specific direction. candela, a unit of measurement that refers to the luminous intensity from a light source in a specific direction. electrode that emits electrons. A fluorescent lamp cathode emits or discharges electrons to the cathode at the other end of the lamp. cathode of a fluorescent lamp, used to collect the evaporating particles from the cathode, greatly reducing the end-blackening of the glass envelope. parabolic recessed troffers with a high cut-off angle that leaves the upper part of the room's walls relatively unlit and noticeably darker than the lower part of the walls. reflector lamp measured in candelas. American National Standards Institute (ANSI). electrons, including capacitors, resistors, and/or transistors, connected by wires through which electrical current flows. If there is only one path for the current, the circuit is called a "Series Circuit". If there are multiple paths, the circuit is called a "Parallel Circuit". cathode (an electrode that emits electrons) that is not independently heated. cathode (an electron-emitting electrode inside the lamp) is not independently heated although the cathode can become quite hot once the CCFL has been operating. Screw-in CCFLs come in several different wattages (present range is 3W to 18W) and several different shapes (spiral, globe, reflector, A-line, torpedo) and are generally characterized by a very narrow glass tube envelope (2mm-4mm in diameter), a longer rated life than compact fluorescent lamps (often 25,000 hours), and a very good range of dimmability (down to 30%). dichroic filter). This is accomplished by mixing various metal oxides in the glass composition. These colored glass filters are primarily used for aesthetic purposes in lighting. They are not designed for the precise control of the spectral bands, as are optical color filters (dichroic filters). Color Rendering Index (CRI). The CQS measures a light source's ability to render colors. The CQS was designed by the NIST to evaluate LEDs. The scale uses 15 color samples of deeper color compared to the CRI, which uses 8 pastel colors. Kelvin. This term is also referred to as the Correlated Color Temperature (CCT). Here is some information to help you better understand how color temperature can effect your mood and the best applications for certain color temps.
- 2700K - Friendly, Personal, Intimate - Home, Libraries, Restaurants
- 3500K - Friendly, Inviting, Non-threatening - New Offices, Public Reception Areas
- 4100K - Neat, Clean, Efficient - Older Offices, Classrooms, Mass Merchandisers
- 5000K - Bright, Alert, Exacting Coloration - Graphics, Jewelry Stores, Medical Exam Areas, Photography
- 1600K - Sunrise or Sunset
- 1800K - Candlelight & Gaslight
- 2800K - Household Incandescent Lamp
- 3000K - Warm White Fluorescent Lamp
- 3500K - Neutral White Fluorescent Lamp
- 4100K - Cool White Fluorescent Lamp
- 5000K - Professional Light Booth
- 5200K - Bright Midday Sun
- 6500K - Heavily Overcast Sky
Return to Top of Glossarydirect current series circuit portable lamp that usually sits on a desk and provides task lighting for any work done on the desktop. colored glass filters, which are used mostly for aesthetic purposes. glare. This is often accomplished by using diffusers that are translucent in nature such as frosted glass, linear spread lenses, solite lenses, or spread lenses. transparent or translucent piece of glass, silicone, or plastic designed to control light by scattering or diffusing it in order to create softer light without much glare. glare or excessive brightness that travels straight from a light source directly into the viewer's eye rather than being reflected off another surface (indirect glare). Glare hinders visibility and contributes to eyestrain. Direct glare can sometimes be attributed to a poorly designed light fixture, and a light fixture that produces an unusual amount of direct glare is sometimes called a "glare bomb". voltage is applied, resulting in the emission of light. Many different gases are used in discharge tubes, including xenon, neon, argon, mercury, and sodium. lamp that has 2 bases or points of electrical and physical connection that provide extra stability in rough service applications.
Return to Top of Glossaryelectroluminescent Energy Policy Act electron stimulated luminescence UL), is an independent, not-for-profit product safety testing and certification organization. Throughout its long history its name has changed several times. Thomas A. Edison established the Lamp Testing Bureau in 1896. In 1904 Edison renamed his Lamp Testing Bureau the Electrical Testing Laboratories (ETL). In 1977 ETL officially changed its corporate name to ETL Testing Laboratories and in 1996 ETL was renamed the Intertek Testing Services, Ltd. (NOTE: ETL Testing Laboratories, originally organized by the Edison Illuminating Companies, has been conducting electrical performance and reliability tests since 1896. Intertek Testing Services (ITS), which acquired ETL Testing Laboratories from Inchcape in 1996, is recognized by OSHA as a Nationally Recognized Testing Laboratory (NRTL) just as Underwriters Laboratories (UL), the Canadian Standards Association (CSA) and several other independent organizations are recognized. A federal law passed in 1988 established the NRTL program to eliminate provisions that explicitly required or implied that product certification be performed only by standard-writing companies such as UL. Since each NRTL must meet the same OSHA requirements of competency, NRTLs recognized for the same product safety test standard are considered as equivalent in their capability to certify to that standard.) (see www.intertek.com) lumens per watt (similar to miles/gallon for a motor vehicle). A 100-watt light source that produces 1750 lumens of light has an efficacy of 17.5 lumens per watt (L/W). Efficacy for certain light sources:
- Edison's first lamp - 1.4 L/W
- Incandescent Lamps - 10-40 L/W
- Fluorescent Lamps - 35-100 L/W
- Mercury Vapor Lamps - 50-60 L/W
- Metal Halide Lamps - 80-125 L/W
- High Pressure Sodium Lamps - 100-140 L/W
- Theoretical max for white light - 225 L/W
- Product categories must contribute significant energy savings nationwide.
- Qualified products must deliver the features and performance demanded by consumers, in addition to increased energy efficiency.
- If the qualified product costs more than a conventional, less-efficient counterpart, purchasers will recover their investment in increased energy efficiency through utility bill savings, within a reasonable period of time.
- Energy efficiency can be achieved through broadly available, non-proprietary technologies offered by more than one manufacturer.
- Product energy consumption and performance can be measured and verified with testing.
- Labeling would effectively differentiate products and be visible for purchasers.
Return to Top of Glossaryfoot-candle foot-lambert incandesces or lights up when an electric current passes through it. transmit a certain narrow range of light (wavelength) while reflecting or absorbing the wavelengths of light that are not transmitted. See colored glass filter and dichroic filter. low voltage or a line voltage lighting system where the suspended track (sometimes called a monorail) holding the light fixtures in place and also conducting electricity to those fixtures can be bent into creative shapes, sometimes to enhance or emulate the architecture of the space. lux (lx). The relationship between the lux and the foot-candle is 1 fc = 10.76 lux. lumen per square foot of its surface. The brightness of the face of an exit sign is sometimes reported in foot-lamberts. Hertz, or 1 cycle per second. lens developed by the French physicist Augustin-Jean Fresnel for lighthouses. Compared to a conventional bulky lens, a Fresnel lens is much thinner, lighter in weight, larger, and flatter. translucent lens that creates a soft (diffused) light.
Return to Top of Glossarydimmers or electrical receptacles side by side in one wall junction box. transparent, heat-resistant, colored piece of plastic that is used to add color to a light source and is often used in theatrical lighting. task lighting or accent lighting.
Return to Top of Glossaryhigh output hertz filament of a halogen lamp and the blackening of the glass envelope during the life of the lamp. halogen lamp that has a reflective dichroic coating on the inner glass bulb that reflects infrared (heat) energy back to the filament, causing an increase in the output of light without an increase in the wattage supplied to the lamp. portable lamp the metal frame that holds the shade in place - the metal wire component on a fixture that supports the lamp shade. LED light fixtures that lowers the temperature of the LEDs by dissipating their heat. Heat sinks are also found in other electronic devices such as computers and lasers. They are often made of aluminum and have grooves, fins, and sometimes a fan. alternating current. high intensity discharge lamp luminaire designed for and used in spaces with very high ceilings (25ft or higher) like factories, warehouses, and gymnasiums. Also see low bay light fixture. lumens) per watt than most other light sources. HID lamps are available in mercury vapor, metal halide, high pressure sodium, and low pressure sodium types. lamp designed to use high levels of current (800 milliamperes), which corresponds with an increase in lumen output. HO fluorescent lamps are able to operate at low temperatures (down to 0F) and still produce high light levels. HID) light bulb that illuminates by radiation from sodium vapor producing a yellowish color rendering, when supplied with electricity from a ballast. This type of light bulb is often used in street lights and is available with clear or phosphor coated glass envelopes. Often abbreviated as HPS lamps they are considered to be quite efficient producing about 100 lumens/watt. halogen IR lamp ROMEX® is a trademark of the Southwire Company which refers to their specific brand of "non-metalic sheathed electrical cable". The non-metallic sheathing is the outside rubber insulation around the entire cable. The cable inside the sheathing is usually made up of 3 wires: one wire with white insulation (neutral wire), one wire with black insulation (power wire), and one copper wire with no insulation (ground wire). The size of the non-metallic sheathed electrical cable that is used to connect lighting fixtures in a home is usually described as "14/2 with ground" (although this may vary with geographical location). The "14/2" refers to the two insulated wires that are 14 gauge in size and the "ground" refers to the uninsulated copper wire. high pressure sodium lamp
Return to Top of GlossaryInternational Dark-Sky Association Illuminating Engineering Society of North America lux or foot-candles. illuminance www.iesna.com) fiber optic lighting system, which also is made up of fiber optic fibers and sometimes fixtures used at the ends of the fibers to direct the light in a specified manner. The light source used in an illuminator is usually an MR halogen lamp, an MR metal halide lamp, or an LED lamp. filament of a lit light bulb). lamp in which light is produced by the passage of an electric current through a tungsten filament which is heated to the point of incandescence. glare or excessive brightness reflected off another surface separate from the light source. Indirect glare, sometimes referred to as reflected glare, can be a reflection off a computer or television screen or even a magazine. Similar to direct glare, the light source should be considered when trying to prevent indirect glare. luminaires to direct most, if not all, of the light toward the ceiling or wall, providing soft, glare-free illumination without seeing the luminaire directly. fluorescent lamp that uses electricity to generate an electromagnetic field that causes the gaseous mercury atoms inside the glass envelope to emit ultraviolet radiation, which in turn, is converted to visible light by the phosphor coating on the inside of the glass envelope. Induction lamps have no electrodes and, therefore, have longer rated lamp lives than standard fluorescent lamps because the deterioration of the tungsten filaments in a standard fluorescent lamp is usually the main cause of a fluorescent lamp to stop working. wavelengths are longer (about 770 nm to 1100 nm) and frequency lower than those for visible radiation (The visible spectrum is made up of red, orange, yellow, green, blue, indigo, and violet - ROYGBIV, for short.) fluorescent lamps that start instantly without pre-heating the cathodes and without the need for starters. www.darksky.org). direct current into alternating current. Inverters are an integral part of electronic transformers.
Example With an IP rating of IP54, the "5" describes the level of protection from solid objects (protected against dust limited ingress with no harmful deposit) and the "4" describes the level of protection from liquids (protection against water sprayed from all directions with limited ingress permitted). An "X" can be used for one of the digits if there is only one class of protection, e.g., IPX1 describes only the level of protection from liquids (protection against vertically falling drops of water, e.g., condensation). First IP Number - Protection Against Solid Objects
Second IP Number - Protection Against Liquids
- 0 - No special protection
- 1 - Protected against solid objects up to 50 mm, e.g., accidental touch by person's hands.
- 2 - Protected against solid objects up to 12 mm, e.g., person's fingers.
- 3 - Protected against solid objects over 2.5 mm (tools and wires).
- 4 - Protected against solid objects over 1 mm (tools, wires, and small wires).
- 5 - Protected against dust limited ingress (no harmful deposit).
- 6 - Totally protected against dust.
- 0 - No protection.
- 1 - Protected against vertically falling drops of water, e.g., condensation.
- 2 - Protected against direct sprays of water up to 15° from the vertical.
- 3 - Protected against direct sprays of water up to 60° from the vertical.
- 4 - Protected against water sprayed from all directions - limited ingress permitted.
- 5 - Protected against low pressure jets of water from all directions - limited ingress.
- 6 - Protected against temporary flooding of water, e.g., for use on ship decks - limited ingress permitted.
- 7 - Protected against the effect of immersion between 15 cm and 100 cm.
- 8 - Protected against long periods of immersion under pressure.
Return to Top of Glossarykilowatt kilowatt hour color temperature of a light source. watts. kilowatt of electricity used over the period of one hour. junction box) that is removed with a punch and hammer to permit insertion of electrical wire like Romex wire. incandescent lamps that allows the filament to glow hotter and brighter and last longer.
Return to Top of Glossarylamp current crest factor light emitting diode Leadership in Energy and Environmental Design light emitting plasma lamp lumen depreciation LED testing performance. LM-80 designates uniform test methods for measuring lumen maintenance for LEDs. lux incandescent, halogen, xenon, fluorescent, or HID lamp. In everyday usage the terms, "light bulb" or "bulb", are usually used instead of the term, "lamp". In everyday usage the term, "lamp", usually refers to a portable lamp like a table lamp or a floor lamp but in the field of lighting the term, "lamp", refers to what most people call a "light bulb". Strictly speaking, the term, "bulb", refers to the glass envelope part of the "lamp". current to the average current for a ballast. A lamp current crest factor (lccf) above the maximum value set by a lamp manufacturer can shorten the lamp's life. The ANSI standard for lamp current crest factor is < 1.7 socket lamp ages, it produces less and less light, the extent of which depends on the type of lamp in question. The value that indicates the lifetime decay of a lamp’s lumen output as the lamp is operated over time is called lamp lumen depreciation. This is exactly why the published "initial lumens" for a lamp are always greater than the "mean lumens" for that same lamp. Some causes for lamp lumen depreciation may be the depletion of the incandescent filament over time, the accumulation of evaporated tungsten particles on the inside of the incandescent or fluorescent glass envelope, the photochemical degradation of the phosphor coating on the inside of a fluorescent glass tube, and the heat generated at the LED junction. task lighting (lighting by which people perform tasks), accent lighting (lighting used to highlight specific objects such as works of art), decorative lighting (lighting created by very attractive light sources such as chandeliers or mini pendants), and general lighting (lighting that fills the space). This technique (long favored by cameramen and cinematographers) can eliminate ugly shadows in the room and on your face. www.usgbc.org/LEED) optics), a lens is a transparent object that transmits and reshapes the direction of light. Made of clear glass or transparent plastic, a convex-type of lens can converge (focus) light while a concave-type of lens can diverge (spread) light. See spread lens, linear spread lens, and solite lens. troffer or recessed light fixture that is covered by a lens. Many lensed troffers have been replaced in offices with parabolic troffers to reduce glare on computer screens. light bulb, light fixture or retrofit but also the cost of maintaining it, which is often large given the cost of labor, and the cost of the electrical energy needed to operate it, which is often even larger than the maintenance costs. Comparing the life-cycle costs of an old lighting system and a proposed new lighting system is the only fair way to compare the costs of the two systems. To compare only the initial costs of the two light fixtures is not a valid way of comparing the total costs of the two systems. lamp. illuminance fixtures such as street and parking lamps. LEPs use a solid-state device to generate radio waves that, in turn, power the plasma, which emits light. LEPs can have a rated life of 50,000 hours, are quickly dimmable, achieve full power in about 30 seconds, and have a CRI up to 94. wall sconces, recessed downlights, mini pendants, table lamps, floor lamps, track heads, step lights, picture lights desk lamps, and recessed troffers. Synonym: luminaire. lumens, lumens per watt (efficacy), watts, CRI, and color temperature of the LED product. The Department of Energy (DOE) started issuing the Lighting Facts Label to encourage consumer trust in LED products. LED flashlights, nightlights, and holiday lighting are not eligible for the Lighting Facts Label. (see www.lightingfacts.com) illumination lost to a variety of factors such as dirt and dust accumulation, voltage fluctuations, and lamp depreciation to name a few. electromagnetic spectrum). There are many natural light sources such as lightning bugs, stars including our own sun, lightning, aurorae, and many artificial light sources such as fluorescent lamps including CFLs, incandescent lamps (including halogen lamps and xenon lamps), high pressure sodium lamps, metal halide lamps, low pressure sodium lamps, neon lights, cold cathode fluorescent lamps, "light sticks", LEDs of various colors, organic light emitting diodes (OLEDs), light emitting plasma, candle light, gaslight, oil lamps, and kerosene lamps. voltage is 120 volts. (Before 1960 residential line voltage was 110 volts, a standard established by Thomas Edison.) Residential electric clothes dryers, however, operate on 240 volts. In the USA commercial line voltage may be 120 volts or 277 volts. In the USA both the residential and the commercial line voltage may vary by ±10%. Thus, residential line voltage may be as low as 108 volts and as high as 132 volts. The standard line voltage is different in other countries. For example, in Japan it is 100V; in Mexico it is 127V; in China and Russia it is 220V; in France, Germany, Italy, England, New Zealand, and India it is 230V, and in Australia it is 240V. translucent or opaque material and geometrically designed to prevent lamps from being viewed directly within a given angle. Louvers are intended to minimize direct or indirect glare. luminaire specifically designed for ceiling heights of less than 25ft. Also, see high bay light fixture. Color Rendering Index. Low pressure sodium lamps, however, have a very high efficacy and are primarily used for outdoor lighting such as street lighting and parking lot lighting. volts, low voltage lighting systems usually operate on 12 volts and sometimes 24 volts. It is important to note that a low voltage lighting system uses a transformer (electronic or magnetic) to transform the "incoming" voltage (usually 120 volts) to 12 or 24 volts because that is the voltage needed by the light bulbs in that lighting system. That is, the transformer of a low voltage lighting system uses the line voltage supplied in the home/building/facility but the light bulbs in that lighting system use the low voltage supplied by the transformer. light source produces or emits. As a reference, we have provided some lumen values for incandescent lamp wattages. These values are approximate because they can vary with the manufacturer of the lamp, the age of the lamp, the dirt on the lamp, whether the lamp is clear or frosted, the voltage rating of the lamp, and the exact voltage of the circuit.
- 4 watts - 20 lumens
- 7 watts - 45 lumens
- 10 watts - 56 lumens
- 15 watts - 95 lumens
- 25 watts - 232 lumens
- 40 watts - 360 lumens
- 60 watts - 615 lumens
- 75 watts - 960 lumens
- 100 watts - 1100 lumens
- 150 watts - 2850 lumens
- 200 watts - 3800 lumens
- 300 watts - 6280 lumens
Return to Top of Glossarymaximum overall length ballast uses magnetic inductance to regulate the voltage of a fluorescent lamp. Magnetic ballasts are noisier, heavier, and less efficient than electronic ballasts. Since magnetic ballasts do not alter the frequency of the electricity supplied to the lamp(s), a flicker or stroboscopic effect can be expected. Some people are more affected by this flickering of the light source and can develop headaches as a result. transformer includes an iron core wrapped with two sets of wires. The transformer "transforms" line voltage (usually 120 volts) into low voltage (usually 12 or 24 volts). One set of the wires connects to the line voltage side, which is called the primary side of the transformer while the second set of wires connects to the low voltage side, which is called the secondary side. Magnetic transformers are often larger, heavier, noisier, and less efficient than electronic transformers. lamp — from tip to tip, from the top of the glass envelope to the bottom of the base. lamp life; also sometimes called "design lumens". fluorescent (including CFLs), metal halide, and high pressure sodium light bulbs during their manufacturing process. It is a silvery-looking liquid metal at room temperature that is a neurotoxin; that is, a toxic substance that can attack the nervous system and brains of humans. high intensity discharge (HID) light bulb that produces light by radiation from mercury vapor, when supplied with electricity from a ballast. Mercury vapor light bulbs usually have very long lifetimes and are available with clear or phosphor-coated glass envelopes. The Energy Policy Act (EPAct) of 2005 included a provision that no new ballasts for mercury vapor light bulbs may be imported or manufactured for "general illumination use" in the U.S., effective January 1, 2008. scotopic vision and photopic vision taking into account the total sensitivity of the rod cells in the human eye for the green-blue range with the color perception of the cone cells. This, however, gives inaccurate visual acuity and color discrimination. high intensity discharge (HID) light bulb that produces light by radiation from certain metallic vapors (such as scandium, sodium, thallium, and indium), when supplied with electricity from a ballast. Known for producing accurate color rendition with a range of 65-90 and are, therefore, often used to light large gymnasiums and athletic stadiums; can be produced with almost any color temperature from 2700K to 20,000K; relatively unaffected by ambient temperatures and can, therefore, be used indoors and outdoors; has high efficacy of between 65-115 lumens/watt, which makes it approximately 5 times as efficient as a typical incandescent light bulb; has a long life of 15,000-20,000+ hours luminaire can be placed directly high on a tree to achieve this landscaping effect. occupancy sensor; synonymous with motion detector. halogen multi-faceted reflector lamp that measures 11/8 inches in diameter and which directs a sharp, well-defined beam of light. halogen multi-faceted reflector lamp that measures 16/8 inches in diameter and which directs a sharp, well-defined beam of light.
Return to Top of GlossaryNational Association of Independent Lighting Distributors National Electric Code National Electrical Manufacturers Association National Institute of Standards and Technology nanometer www.naild.org) www.nema.org) www.nist.gov) incandescent light bulb makes it less "yellowish" and more like natural outdoor light; however, the use of these "daylight" light bulbs can "expose" the flaws or inconsistencies in things. current is applied. Neon (Ne) is found in the atmosphere and is considered rare on Earth compared to its presence in the universe.
Return to Top of GlossaryLEDs except that the electroluminescent layer is composed of organic material. infrared, ultrasonic, and/or audio technology to detect the presence of people in an area. transmit any visible light. A wooden door, aluminum foil, and bricks are all examples of opaque materials. infrared, ultraviolet, and visible light and how they interact with matter. Optics also focuses on the construction of instruments/accessories/devices that detect and manipulate light, such as mirrors, lenses, filters, and louvers.
Return to Top of Glossarypassive infrared troffer or recessed light fixture that was made popular in offices due to its ability to reduce glare on curved surfaces like a computer screen compared to the lensed troffer. This troffer has a parabolic shape to the housing of each lamp. Parabolic troffers waste a high amount of energy due to a large percentage of light not leaving the troffer and are outdated with the advances in computer screen technologies such as LED and LCD. louver, usually made of plastic, with a cell-like structure of open cubes designed to control glare in a troffer. Paracubes are often installed in offices to combat glare on computer screens. reflector. A PAR lamp, which may use an incandescent filament, a halogen filament tube, or an HID arc tube is a precision pressed-glass reflector lamp that reflects light coming from the filament much like a parabola. PAR lamps (such as PAR20, PAR30, and PAR38) rely on both the internal reflector and prisms in the lens for the control of the light beam. motion sensor that detects the movement of heat sources. luminaire that illuminates a walkway. Path lights can be solar powered or wired and be programmed to turn on and off at certain brightness levels throughout the day. fluorescent lamp that transforms some of the ultraviolet energy created inside the lamp into visible light. luminaires accordingly. It is often used with a street light to turn the light on at dusk and off at dawn. luminaire designed to project light over a picture/painting/photograph. A picture light can be attached to the picture frame or the wall or be recessed in the ceiling. compact fluorescent lamp coined by Philips Lighting, a large manufacturer of lamps. outlet in only one orientation - a plug with 1 prong that is wider than the other and serves to "ground" the connection. Polarized plugs are designed to protect people from being shocked and prevent voltage from reaching an appliance switched "off". voltage and current are out of phase in an electrical circuit. A power factor that is near 1.0 is considered good because this means that the electrical circuit is able to do work efficiently. The closer the power factor is to 0, the more inefficient the electrical circuit is. A high power factor (HPF) is generally considered to be 0.90 and above and a normal power factor (NPF) is generally considered to be between 0.5 and 0.6. fluorescent lamp. Also known as switch start fluorescent lamps, preheat fluorescent lamps require a starter unlike rapid start fluorescent lamps. spread lens
Return to Top of Glossaryhalogen lamp wire nut"). radio frequency interference starter and takes about 1 to 2 seconds to emit light. The ballast preheats the electrodes within the fluorescent lamp and initiates the arc without a starter or the application of high voltage to the electrodes of the lamp. incandescent lamp that has a rated life of 1000 hours and is designed to be used with 130 volts but is used with 120 volts instead will have an "Actual Life" of 2610 hours. outlet that connects the power supply to a plug. A receptacle can have 2 to 4 holes, including a connection for grounding. light source, which could be an incandescent, halogen, fluorescent, LED, or HID lamp. Synonyms: downlight, can, recessed can, high hat, pot light. reflected by a surface to the amount of light originally striking that surface; reflectance = reflected light/incident light. refraction, which is the bending of light as it passes through a different transparent or translucent medium. opaque material that controls light into a certain direction. A component of PAR lamps, reflectors can be used to intensify light. A mirror is an example of a flat reflector. incandescent, cone-shaped, light bulb that has a reflecting surface on the inside rear of the glass envelope. Variations of this lamp type are the bulged reflector lamp (BR lamp), the ellipsoidal reflector lamp (ER lamp), and the small reflector lamp (R). Since mid-2008 BR and ER light bulbs greater than 65 watts, used mostly in commercial retail applications, have been outlawed from being manufactured. These banned light bulbs can be replaced with more-efficient halogen PAR light bulbs. Also since mid-2008, R20 light bulbs can be no more than 45 watts. If a higher wattage reflector-type lamp is needed, a more efficient halogen PAR20 light bulb can be used. The 65-watt BR30 light bulb, commonly used in homes and restaurants, may still be manufactured and sold. transparent medium into another transparent medium (e.g., from air to glass, from water to air, from air to vacuum, diamond to air). transparent material, such as a lens or a prism, that bends or refracts light HID lamp to come to full brilliance after it has been turned off. lamps, ballasts, luminaires, or equipment that improves the efficiency or safety of the lighting system. reflector lamp household wire". LEDs or miniature incandescent light bulbs (placed about 1.0in apart) connected in clear plastic tubing (about 0.5in in diameter) that can be plugged into an outlet
Return to Top of Glossaryseasonal affective disorder solid state lighting wall sconce. Not to be confused with a scone, which is a flat, round cake of wheat flour. wavelengths of light around 498 nm (green-blue). illumination. Self-luminous exit signs do not require any other power source and can last nearly 20 years before they need to be replaced. reflector that produces a diffuse or distorted image as opposed to a specular reflection like that seen in a mirror. open circuit and the electric current would not be able to get to the other light fixtures. Another term for a series circuit is a "daisy chain". cut-off angle are complementary angles, meaning they total 90 degrees. The greater the shielding angle, the more glare is reduced. linear spread lens luminaire that provides a means of physically holding the lamp base and connecting the lamp to the luminaire's electric circuit; (2) a power point usually mounted in a wall that serves as a connection for electrical plugs. Sockets have holes or slots for electrical plugs and are sometimes called "outlets". LED, an OLED, or a PLED) rather than electrical filaments (like incandescent, halogen, or xenon) or plasma (like fluorescent, metal halide, or high pressure sodium). illumination of the work plane. fiber optic lighting and is useful in elegant locations. diffuse), in accordance with the laws of geometrical optics, as with a mirror or a highly polished metallic surface. ballast for the purpose of starting an electric discharge lamp like a fluorescent lamp or an HID lamp. fluorescent light source powered by a low frequency alternating current (AC). The moving images on televisions and other rapidly moving objects can appear to stand still or flicker. Often associated with fluorescent lighting, the stroboscopic effect can be substantially reduced with an electronic ballast.
Return to Top of GlossaryUnder cabinet lighting used in a kitchen is a good example of task lighting. incandescent lamp that offers 3 levels of illumination (brightness) by using 2 different filaments with one filament providing the lowest level of illumination, the second filament providing a higher level of illumination, and the 2 filaments together providing the highest level of illumination. A few compact fluorescent lamp (CFL) models now also offer 3 levels of illumination but by using a different mechanism. magnetic transformer with a donut-shaped core. Toroidal transformers are generally more efficient, lighter weight, quieter, and cooler than conventional "EI magnetic transformers". Toroidal transformers can be loaded 100%, meaning a 600-watt transformer can power 600 watts of lighting. EI magnetic transformers, however, should be loaded approximately 80%, which means that a 600-watt EI magnetic transformer should be used to power about 480 watts. luminaires attached to a track mounted on a ceiling or wall to illuminate a space. The track provides the current for the various luminaires, which allows them to be manipulated into different positions. transmits most, if not all, of the visible light incident upon it with very little, if any, distortion. A typical glass window pane, the air, and clear plexiglas are all examples of transparent materials. luminaire (light fixture) that often uses 1-4 fluorescent lamps (light bulbs), usually measures 24in by 48in or 24in by 24in, and is usually installed with the opening flush with the ceiling. There are several types of troffers, for example: lensed troffer, parabolic troffer, basket troffer, and volumetric troffer. lamp and bulb for more information. filament in incandescent light bulbs. halogen lamp compact fluorescent lamp (CFL) made up of two parallel glass bulbs or tubes. Also referred to as a "PL" lamp (by Philips Lighting) or a "biax" lamp (by GE) or a "dulux" lamp (by Osram-Sylvania).
Return to Top of GlossaryUnderwriters Laboratory ultraviolet radiation fluorescent lamp that is shaped like the letter "U"; sometimes called a U-shape fluorescent lamp. ETL), is an independent, not-for-profit product safety testing and certification organization. The UL symbol with the letter, "C", and the letters, "US", indicate that the lighting product is UL listed in both Canada and the United States. (see www.ul.com) illuminance over a given plane. Greater uniformity means less variation of illuminance. pendant light, an entire row of linear luminaires, or a semi-flush mount ceiling fixture) the amount of light lumens directed upward at or above 90 degrees. Also, refers to a single light fixture that is generally placed on the floor or recessed in the floor that projects light upward. UV Filters.
Return to Top of Glossaryvisual comfort probability very high output luminaire that is shielded by an opaque panel parallel to the wall which directs light upward and downward from the luminaire. luminaire that is positioned above or on either side of a bathroom mirror. fluorescent lamp designed to use even more current than a high-output fluorescent lamp, which allows for an even greater lumen output. glare acceptable in a specific location from a specific direction. The higher the VCP, the more comfortable observers find the space. circuit, meaning the greater the current running through a circuit. The standard household line voltage in the U.S. is approximately 120 volts. The unit is named after Alessandro Volta, an Italian physicist who made the first electric cell. See voltage. volts; the electric pressure that exists between two points and is capable of producing a flow of current when a closed circuit is connected between the two points; the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; synonyms: electrical potential, electromotive force, EMF; Formulae: volts = amps x ohms, V = I x R, voltage = electrical current x electrical resistance. transformer and the light fixtures, and/or using a DC transformer. troffer that is designed to eliminate the cave effect associated with parabolic troffers. The volumetric troffer distributes light more evenly than its predecessors and its light sources are concealed by diffuse translucent shielding.
Return to Top of Glossaryampere passing across a potential difference of 1 volt is equal to 1 watt (W=AV). One watt also equal 1 joule per second (W=J/s). The unit is named after James Watt because of his work on steam engine technology. In lighting, watts indicate the amount of power a light bulb consumes not the light output of that light bulb. lamp or light fixture measured in "watts". One watt is equal to the power dissipated by 1 ampere of electrical current flowing across a resistance of 1 ohm or the power produced by 1 ampere of electrical current under an electromotive force of 1 volt. One horsepower is equal to 746 watts. Formulae: watts = volts x amps, P = V x I, electrical power = electromotive force x electric current. Note: the wattage rating of light bulb does not indicate how much light is produced by that light bulb. nanometers while the wavelength of violet, at the other end of the visible spectrum, is about 400 nanometers. - a measure of the distance between the corresponding points in consecutive cycles of a wave (such as consecutive troughs or crests). Wavelengths of the electromagnetic spectrum are generally measured in nanometers.
Return to Top of Glossaryincandescent light bulb that contains xenon gas in the glass envelope. The primary reason that this is done is to lengthen the average rated life of the lamp. Depending on the lamp a typical xenon lamp may have a rated life of 10,000 hours whereas a similar halogen lamp may have a rated life of 2,000 hours. Unlike halogen lamps, xenon lamps may be touched with bare hands without affecting the rated life of the lamp. Xenon lamps also operate at cooler temperatures than comparable halogen lamps. Like halogen lamps, xenon lamps may be dimmed (using the right dimmer) whether the lamp is rated for low voltage (12 volts or 24 volts) or line voltage (120 volts).
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