Friday, December 30, 2011
Footcandle (fc)
A unit of illuminance or light falling onto a surface. It stands for the light level on a surface one foot from a standard candle. One footcandle is equal to one lumen per square foot. (See Lux)
Fluorescence HO
Fluorescence HO and VHO lamps require special ballast that generate hogher currents than standard ballasts and operated the lamps at higher wattage than standard lamps. These lamps are generally less efficient than the standard product. Metal holide HO and XHO lamps operate an the same wattage but are more efficient and produce higher light output than standard lamps.
Fluorescent Lamp
A high efficiency lamp utilizing an electric discharge through low pressure mercury vapor to produce ultraviolet (UV) energy. The UV excites phosphor materials applied as a thin layer on the inside of a glass tube which makes up the structure of the lamp. The phosphors transform the UV to visible light.
Fluorescence
A physical phenomenon whereby an atom of a material absorbs a photon of light an immediately emits a photon of longer wavelength. If there is a significant delay the phenomenon is called phosphorescence rather than fluorescence. It is interesting that "phosphors" used in lamps exhibit "fluorescence," not "phosphorescence". (See Phosphor)
Floodlight
A luminaire used to light a scene or object to a level much brighter than its surroundings. Usually floodlights can be aimed at the object or area of interest.
Flood
Used to refer to the beam pattern of a reflector lamp, which disperses the light over a wide beam angle, typically 20 degrees or more. ("Flood" as opposed to "spot").
Thursday, December 29, 2011
Flicker
The periodic variation in light level caused by AC operation that can lead to strobe effects.
Fixture Requirements
Describes fixture requirements for HID lamps.
O = Open or Enclosed Fixtures
E = Enclosed Fixtures Only
S = Lamps operated in a vertical position (Base Up or Down) ±15º, can be used in an open fixture. Lamps burned in any other orientation must be used in "enclosed fixtures only".
O = Open or Enclosed Fixtures
E = Enclosed Fixtures Only
S = Lamps operated in a vertical position (Base Up or Down) ±15º, can be used in an open fixture. Lamps burned in any other orientation must be used in "enclosed fixtures only".
Filament Design
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.
Field Angle
The angular dimension of the cone of light from reflectorized lamps (such as R and PAR types) encompassing the central part of the beam out to the angle where the intensity is 10% of maximum (See Beam Angle).
Federal Communications Commission (FCC)
The U.S. Federal Agency that regulates emissions in the radio frequency portion of the electromagnetic spectrum. Part 18 of the FCC rules specifies electromagnetic interference (EMI) from lighting devices operating at frequencies greater that 9 kilohertz (kHz). Typical electronically-ballasted compact fluorescent lamps operate in the 24-100 kHz frequency range.
Eye Sensitivity
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)
Energy-Using Products (EuP)
The EuP Directive establishes a framework for the setting of eco-design requirements for energy-using products. It aims to improve the environmental performance of products throughout the life-cycle, by systematic integration of environmental aspects at a very early stage in the product design.
EoL (End-of-Life Protection)
A circuit that senses that a lamp has reached end of life (compact fluorescent lamps and small diameter linear fluorescent lamps) and turn off power to the lamp. Continuing to power the lamp beyond end of life can result in overheating of the lamp ends.
Energy Policy Act (EPACT) Indicator
Means this lamp is Federally regulated for Energy Efficiency (See Energy Policy Act).
Energy Policy Act (EPACT)
Comprehensive energy legislation passed by the U. S. Congress in 1992. The lighting portion includes lamp labeling and minimum energy efficacy (lumens/watt) requirements for many commonly used incandescent and fluorescent lamp types. Federal Canadian legislation sets similar minimum energy efficacy requirements for incandescent reflector lamps and common linear fluorescent lamps.
Elliptical Reflector (ER) Lamp
An incandescent lamp with a built-in elliptically-shaped reflecting surface. This shape produces a focal point directly in front of the lamp which reduces the light absorption in some types of luminaires. It is particularly effective at increasing the efficacy of baffled downlights.
Electronic Ballast
A short name for a fluorescent high frequency electronic ballast. Electronic ballasts use solid state electronic components and typically operate fluorescent lamps at frequencies in the range of 25-35 kHz. The benefits are: increased lamp efficacy, reduced ballast losses and lighter, smaller ballasts compared to electromagnetic ballasts. Electronic ballasts may also be used with HID (high intensity discharge) lamps (See Magnetic Ballast).
Electromagnetic Spectrum
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.
Electromagnetic Inference (EMI)
High frequency electronic ballasts and other electronic devices can produce a small amount of radio waves which can interfere with radio and TV. Federal mandated requirements must be met for EMI levels before an electronic device is considered FCC compliant. (FCC is the Federal Communications Commission).
Electrodeless Lamps
Light sources where the discharge occurs in a chamber with no electrodes (no metal.) The energy for the discharge is supplied by radio frequency excitation, e.g. microwaves (See Genura).
Electrode
Any metal terminal emitting or collecting charged particles, typically inside the chamber of a gas discharge lamp. In a fluorescent lamp. In a fluorescent lamp, the electrodes are typically metal filaments coated with special powders called emisison mix.Negatively charged free electrons emitted by one electrode (anode), creating an electric current and arc between electrodes.
Electrical Testing Laboratory (ETL)
Independent testing laboratory that performs ballast tests and certifies accuracy of performance data.
Electrical Discharge
A condition under which a gas becomes electrically conducting and becomes capable of transmitting current, usually accompanied by the emission of visible and other radiation. An electric spark in air is an example of an electrical discharge, as is welder's arc and a lightning bolt. (See Arc, Electrodeless Lamps)
ELC (European Lamp Companies Federation)
Created in 1985, the European Lamp Companies Federation (ELC) is both the forum and the voice of the lamp industry in Europe. It represents the leading European lamp manufacturers, which collectively directly emplay 50,000 people and account for 95 percent of total European production, with annual turnover in Europe of €5 billion. From the outset. ELC objectives have been to promote efficient lighting practice for a sustainable environment and the advancement of human comfort, health and safety. To this end ELC monitors, advises and co-oparates with legislative bodies in developing European Directives and Regulations relevant to the European lamp industry.
Wednesday, December 28, 2011
Efficiency Ballast
The ratio of output power divided by input power. A premium ballast would have an electrical efficiency of a luminaire or fixture is the percentage of the lamp lumens that actually comes out of the fixture.
Efficiency
The efficiency of a light source is simply the fraction of electrical energy converted to light, i.e. watts of visible light produced for each watt of electrical power with no concern about the wavelength where the energy is being radiated. For example, a 100 watt incandescent lamp converts 7% of the electrical energy into light; discharge lamps convert 25% to 40% into light.
The efficiency of a luminaire or fixture is the percentage of the lamp lumens that actually comes out of the fixture. (see Luminous Efficacy)
The efficiency of a luminaire or fixture is the percentage of the lamp lumens that actually comes out of the fixture. (see Luminous Efficacy)
Efficacy
A measurement of how effective the light source is in converting electrical energy to LUMENS of visible light. Expressed in LUMENS-PER-WATT (LPW) this measure gives more weight to the yellow region of the spectrum and less weight to the blue and red region where the eye is not as sensitive.
GE Edison Award
An annual competition where lighting designers submit their best projects. The entries are judged by an international panel and awards are presented at a banquet accompanying Light Fair, the North American trade show for the lighting industry.
Eccentricity (Maximum)
In High Intensity Discharge lamps the Bulb to Arc Angle is the angle off of center between electrodes and bulb. The Bulb to Base Angle is the angle off of center that the bulb is from the base.
Department of Transportation (DOT) Type
The US Department of Transportation lamp number stamped in the glass lens or on the base of headlamps.
Distance Outside Legs
For U-shaped Fluorescent lamps, this measurement is the average distance to the outside of each leg.
Distance Between Leg Centers
For U-shaped Fluorescent lamps, this measurement is the average distance between the centers of each leg.
Driver
Control gear for LED-based products. Can be either constant current or constant voltage. For LED lamps the driver is often integral (see Self-Ballast Lamps).
Discharge Lamp
A lamp where light is emitted from an electrical discharge between two electrodes as opposed to filament lamp. Examples are: Fluorescent lamps and HID (High Intensity Discharge) lamps like Metal Halide, Mercury and High Pressure Sodium.
All Discharge lamps require some kind of current limiting device, e.g. a ballast, to operate them.
All Discharge lamps require some kind of current limiting device, e.g. a ballast, to operate them.
Distance Between Legs
For U-shaped Fluorescent lamps, this measurement is the average distance between the inner walls of the legs.
Dimmer, Dimming Control
A device used to lower the light output of a source, usually by reducing the wattage it is being operated at. Dimming controls are increasing in popularity as energy conserving devices.
Dichroic Reflector (or Filter)
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.
Declaration of Conformity (DoC)
A self-declaration of a product on its compliance to the Electromagnetic Compatibility Directive and the Low Voltage Directive and it can bare CE conformity marking (EU).
Daylight Lamp
A lamp resembling the colour of daylight, typically with a colour temperature of 5500 K to 6500K
Daylight Harvesting
Lighting design for building interiors that makes of daylight as a way of reducing energy consumption.
Crest Factor (Max Current)
The ratio of the peak lamp current to average lamp operating current (RMS). The lower the current crest factor is, the gentler the ballast is on the lamp.
covRguard™
A special plastic shielding on the outside of tubular fluorescent lamps that effectively contains shattered glass particles if the lamp is broken. Such protection is mandated in many industries and locations, e.g. food packaging.
Current Type (AC/DC)
Whether the operational voltage is based on Alternating Current or Direct Current.
Cost of Light
Usually refers to the cost of operating and maintaining a lighting system on an ongoing basis. The 88-8-4 rule states that (typically) 88% is the cost of electricity, 8% is labor and only 4% is the cost of lamps.
Cosine-Corrected
An illuminance meter that measures the light level correctly irrespective of the angle the light is coming from. (See Illuminance Meter)
Core & Coil Ballast
A ballast that uses a "Core & Coil" assembly to operate fluorescent or HID lamps. Refers to Copper or aluminium windings on a steel core.
Core
Component of electromagnetic ballast that is surrounded by the coil. Core is comprised of steel laminations or solid ferrite material.
Cool White
A term loosely used to denote a colour temperature of around 4100 K. The Cool White (CW) designation is used specifically for T12 and other fluorescent lamps using halophosphors and having a CRI of 62.
Constant Color™
A GE Registered name for lamp families which show very little colour shift over life, Such as GE's Precise™ MR16 lamps and GE's ceramic metal halide (CMH) lamps.
Compact Fluorescent Lamp (CFL)
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.
Colour Temperature (Correlated Colour Temperature - CCT)
A number indicating the degree of "yellowness" or "blueness" of a white light source. Measured in kelvins, CCT represents the temperature an incandescent object (like a filament) must reach to mimic the colour of the lamp. Yellowish-white ("warm") sources, like incandescent lamps, have lower colour temperatures in the 2700K-3000K range; white and bluish-white ("cool") sources, such as cool white (4100K) and natural daylight (6000K), have higher colour temperatures. The higher the colour temperature the whiter, or bluer, the light will be (See Chromaticity).
Colour Rendering Indicator
Draws attention to the fact that this is a lamp with high colour rendering, which helps objects and persons illuminated to appear more true to life.
Colour Rendering Index (CRI)
An international system used to rate a lamp's ability to render object colours. The higher the CRI (based upon a 0-100 scale) the richer colours generally appear. CRI ratings of various lamps may be compared, but a numerical comparison is only valid if the lamps are close in colour temperature temperature. CRI differences among lamps are not usually significant (visible to the eye) unless the differences is more than 3-5 points.
Colour Bin
LEDs are often sorted according to their CIE chromaticity coordinates into different groupings or "bins".
Coil
Windings of cooper or aluminium wire surrounding the steel core in ballast. Also refers to the entire assembly comprising the inductor or transformer.
Coefficient of Utlization (CU)
In genereal lighting calculations, the fraction of initial lamp lumens that reach the work plane. CU is a function of luminaire efficiency, room surface reflectances an room shape.
Class P Thermal Protector
A switching device sensitive to current and heat that automically disconnects ballast if the temperature exceeds UL temperature limitations.
Chromaticity Coordinates
A system for measuring the colour 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.
Tuesday, December 27, 2011
Chromaticity
Measure to identify the colour of a light source, typically expressed as (x.y) coordinates on a chromaticity chart (see Colour Temperature)
Chip
A very small square of semi-conducting material. Also known as a "die", it is the "active" light-emitting component of an LED.
Ceramic Metal Halide (CMH)
A type of metal halide lamp that uses a ceramic material for the arc tube instead of glass quartz, resulting in better colour rendering (>80 CRI) and improved lumen maintenance.
Center Beam Candlepower (CBCP)
Refers to the luminous intensity of the center of the beam of a blown or pressed reflector lamp (such as a PAR lamp). Measured in candelas.
Cathode Resistance
Resistance of the cathode in a fluorescent lamp. It is measured "cold" before the lamp is turned on (Rc) or "hot" after the lamp is turned on (Rh). The ratio of the hot resistance to the cold resistance is also measured (Rh/Rc).
Capacitor
Device in electronic circuit (part of ballast or a separate element) that stores electrical energy. Often used for power factor correction and lamp regulation.
Sunday, December 25, 2011
Candlepower Distribution Curve
A graphical presentation of the distribution of light intensity of a light source, usually a reflector lamp or luminaire.
Candlepower (Mean Spherical)
Initial mean spherical candlepower at the design voltage. Mean spherical candlepower is the generally accepted method of rating the total light output of miniature lamps. To convert this rating to lumens, multiply it by 12.57 (4 pil).
Candlepower
An obsolete term fo luminous intensity; current practice is to refer to this simply as candelas. (see Candela)
Candela (cd)
The measure of luminous intensity of a source in a given direction. The term has been retained from the early days of lighting when a standard candle of a fixed size and composition was defined as producing one candela in every direction. A plot of intensity versus direction is called a candela distribution curve and is often provided for reflectorized lamps and for liminaires with a lamp operating in them.
Canadian Standards Association (CSA)
An organization that writes standards and tests lighting equipment for performance as well as electrical ad fire safety. Canadian provincial laws generally require that all products sold for consumer use in Canada must have CSA or equivalent approval.
Canadian Energy Standards
Indicates ballast complies with Canadian Energy Standards and meets the requirements of CAN/CSA C654-M91.
Bulb Size
Bulb shape followed by its size (the maximum diameter of the bulb expressed in eights of an inch). For Compact Fluorescent products. "S", "D", "T" and "Q" are used to represent Single, Double, Triple and Quad Biax® sizes. The code also includes a reference such as T4 to represent the size of the tube. Rectangular headlamps are designated as "Rect" and the number of millimeters as "Rect" and the number of millimeters horizontally.
Saturday, December 24, 2011
Bulb Material or Coating
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.
Bulb
A loose way referring to a lamp. "Bulb" refers to the outer glass bulb containing the light source.
Bottom Exit Studs (BES)
(LFL plug-in ballasts) A configuration with screw studs mounted on the base plate or bottom og the ballast. The screws are 3/8" (inches) long with a #8-32 thread size (#8-32 nut). They are mounted on a two-inch center. The studs are usually used to mount the ballast directly onto a junction box plate.
Blacktop
Whether or not the top of the miniature lamp has a blacktop coating. The coating is used to central unwanted brightness or glare.
Black Light
A popular referring to alight source emitting mostly near UV (320 to 400 nm) and very little visible light.
Blackbody
A hot body with an incandescent black surface at a certain temperature used as a standard for comparison. Note that a black surface is the best radiator possible. A tungsten filament will emit slightly less radiation than a blackbody at the same temperature.
Friday, December 23, 2011
Biax™
The GE trademark for its biaxial family of high efficiency and long-life compact fluorescent lamps. DBX (Double Biax), TBX (Triple Biax) and QBX (Quad Biax) refer to the number of U-shaped legs present in the lamp.
Bi-Pin
Any base with two metal pins for electrical contact. This is typical base for a fluorescent tube of 1 to 4 feet in length. It consists of 2 prong contacts which connect into the fixture. Medium bi-pins are used with type T-8 and T-12 tubular fluorescent lamps and miniature bi-pins are used for tubular T-5 fluorescent lamps.
Beam Spread (Approximate)
For reflector type lamps. The total angle of the directed beam (in degrees horizontal or vertical) to where the intensity of the beam falls to 50% or 10% of the maximum candlepower value as indicated.
Beam Angle
The angular dimension of the cone of light from reflectorized lamps (such as R 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 the ordering code for the reflectorized lamps. Example: The 50PAR30/HIR/NFL25 is a 50 watt PAR30 narrow flood lamp with beam angle of 25 degrees. (see Field Angle).
Bayonet
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.
Base Temperature (Maximum)
The maximun operating temperature permitted for the base in Celcius. Fixture manufacturers need to ensure that these conditions are satisfied in their fixture.
Thursday, December 22, 2011
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 type 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.
Ballast Hum
Sound generated by the vibration of laminations in the iron core of the transformer or inductor present in the ballast.
Ballast Factor (BF)
This is the percentage of a lamp's rated lumen output that can be expected when operated on a specific, commercially available ballast. For example, a ballast with a ballast factor of 0.93 will result in the lamp's emitting 93% of its rated lumen output. A ballast with a lower BF results in less light output and also generally consumes less power.
Ballast Efficacy Factor (BEF)
Defined as ballast factor x 100 divided by input watts. The value is used to evaluate various lighting systems based on light output and power input. The BEF can only be used to compare systems operating the same type and quantity of lamps.
Ballast
An auxiliary piece of equipment required to start and to properly control the flow of current to gas discharge light sources such as fluerescent and high intensity discharge (HID) lamps.
Auto Reset Shutdown Circuit
Circuit senses lamp end life and will automatically shut off power to the lamp(s). When a new lamp is inserted in the socket, the ballast resets and turns on the lamp automatically. Some shutdown circuits require the power to be cycled be fore a new lamp will re-light.
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.
Wednesday, December 21, 2011
Arc Lenght
In high intensity Discharge lamps this is the distance between the electrode tips, which represents the physical length of the electrical discharge.
Arc Lamp
A light source containing an arc. Also called discharge lamp or an arc discharge lamp. (see Electrical Discharge).
Arc
A general term for a high intensity electrical discharge occurring between two electrodes in gaseous medium. Usually accompanied by the generation of heat and emission of light. (see Electrical Discharge)
Application
Also called "lighting application" it refers to the particular use the lamp is being put to. (e.g. high-bay industrial application or retail lighting application). The term can also refer in a general way to "application engineering" which deals with specific parameters and usage of light sources. (e.g. how to do a lighting layout, where to place fixtures and so on).
ANSI Codes
These are 3-letter codes assigned by the American National Standards Institute. They provide a system of assuring mechanical and electrical interchangeability among similarly coded lamps from various manufactures.
American National Standards Institute
American National Standards Institute (ANSI) A consensus-based organization which coordinates voluntary standards for the physical, electrical and performance characteristics of lamps, ballast, luminaires and other lighting and electrical equipment.
Amperes
("Amps.") A measure of electrical current. In incandescent lamps, the current is related to voltage and power as follows: Watts (power) = Volts x Amps (currents).
Ambient Lighting
The general lighting present in an area excluding task lighting and accent lighting but including general lighting and daylight streaming in.
Tuesday, December 20, 2011
Accent Lighting
Directional lighting to emphasize a particular object or draw attention to a display item.
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