Ampere (Amp):
A unit to quantify the intensity of electric current flow. Commonly referred to as Amps (A) or current (I).

Amperes (Amps):

ANSI (American National Standards Institute):
A non-profit accredited standards organization established to administer a voluntary industry standards process in the United States.

The inner tube of a high intensity discharge (HID) lamp, that contains an electric arc which produces light when an electric current passed through the tube.

Average Rated Life:
The life value assigned to a particular lamp type. Statistically, Average Rated Life is a numeric value in hours of the median, (50% point), of a population of lamps that remain operating. For Example, if a lamp had an Average Rated Life of 10,000 hours and 100 new lamps were installed in the same location, approximately 50 lamps would still be operating after 10,000 hours.

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A device that, by means of resistance, inductance, capacitance, or electronic elements, singly or in combination, controls the current, voltage and waveform to the required values for proper lamp starting and operation. Capacitors for power factor correction and capacitor discharge resistors may form part of such ballast.

Ballast Factor (BF):
Measure of light output from lamp operated by commercial ballast, as compared to a laboratory standard reference ballast. BF = Lumens (Commercial Ballast) / Lumens (Reference Ballast)

Ballast Losses:
The power consumed by the ballast when it is operating a lamp. The ballast loss is calculated by subtracting the input power from the lamp power.

Ballast Noise “Hum”:
Sound made by operating Core & Coil assemblies in both electromagnetic and electronic ballasts, generated by the vibration of laminations in the electromagnetic field that transforms the voltage and current used by discharge lamps. The sound made by high frequency electronic ballasts is lower, and any noise made by models with electronic power factor connection circuits is inaudible.

A mechanical device that supports the lamp and may provide an electrical connection to operate the lamp.

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Device in ballast that stores electrical energy.

CCF (Current Crest Factor, Lamp):
The peak lamp current, divided by the RMS lamp current. Low crest factors are important for achieving rated lamp life. CCF = Peak Lamp Current (Amps) / RMS Lamp Current (Amps)

Centigrade (C):
Celsius temperature scale where 0°C = 32°F and 100°C = 212°F.

The dominant or complimentary wavelengths (colors) and purity aspects of the colors taken together.

Color Shift:
The change in a lamp’s color appearance, over life, measured in Kelvin compared to the initial color temperature rating.

Component of electromagnetic ballast that is surrounded by the coil and comprised of steel laminations or solid ferrite material.

Core & Coil Ballast:
Another term for electromagnetic ballast.

Correlated Color Temperature:
A specification of the color appearance of a lamp relating its color to that of a reference source heated to a particular temperature, measured in degrees Kelvin (K).

Cost of Light:
The total cost of owning a lighting system, which includes fixture, lamp, installation, maintenance labor, and electrical power costs.

CRI (Color Rendering Index):
An international system used to rate a lamp’s ability to render object colors. The higher the CRI (based upon a 0-100 scale), the better colors appear. CRI ratings of various lamps may be compared, but a numerical comparison is only valid if the lamps are also rated for the same chromaticity. CRI differences among lamps are not usually significant (visible to the eye) unless the difference is more than 3-5 points.

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The measure of a lamp or lighting system to convert electrical energy to radiant luminous energy. Lighting efficacy is expressed in Lumens Per Watt (LPW).

Electromagnetic Interference (EMI):
Electrical interference (noise) generated by electrical and electronic devices. Levels generated by high frequency electronic devices are subject to regulation by the Federal Communications Commission (FCC). Two classifications exist; Non- Consumer (also referred to as Class A or Commercial) and Consumer (also referred to as Class B or Residential).

Electromagnetic Radiation:
Radiation originating in a varying electromagnetic field, such as visible light, radio waves, x-rays, and gamma rays.

Electronic Ballast:
A type of ballast that uses electronic components to provide the open circuit voltage and current regulation to start and sustain a discharge a lamp.

Enclosed Fixture:
A luminaire designed to contain any hot quartz fragments that might result from an arc tube rupture.

EN lamps are Environmental Protection Agency/TCLP compliant as non hazardous waste in that they are completely lead free and contain reduced mercury.

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FCC (Federal Communications Commission):
The U.S. federal agency that is charged with regulating electrical interference emissions of the electromagnetic spectrum. The regulation entitled, “Part 18” deals with electromagnetic interference (EMI) from all lighting devices operating at frequencies higher than 9 kilohertz (kHz).

Fixture Requirement:
An ANSI containment classification of luminaires for specific HID lamp types. The classification code consists of the letters “O” for open, “E” for enclosed and “S” for open luminaires with lamp operating position restrictions.

Footcandle (fc):
A unit of illuminance equal to 1 lumen per square foot or 10.76 lux.

Rate of alteration in an AC current. Expressed in cycles per second or Hertz (Hz).

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Chemicals added to a lamp that neutralizes contaminants such as hydrogen and oxygen, which negatively affect lamp starting and life.

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Hard Glass:
Heat resistant glass that prevents breaking from thermal shock when struck by water. Borosilicate is one type of hard glass used for lamp outer jackets.

Harmonic Distortion:
A measurement of the magnitude of voltage and current harmonics as compared with the amplitude of the fundamental frequency. Harmonic distortion can be generated by a load and fed back into the AC mains, causing distortion of the sinusoidal waveform.

Refers to components of the overall frequency, an integral multiple of the fundamental sine wave frequency.

Hertz (Hz):
Unit used to measure frequency of alteration of electric current or voltage per unit time. Formerly CPS (Cycles Per Second) 1CPS = 1 Hz.

HID (High Intensity Discharge):
An electric discharge lamp in which the light-producing arc is stabilized by the bulb wall temperature and the bulb wall loading is in excess of three watts per square centimeter. High intensity discharge lamp includes groups of lamps commonly known as Mercury, Metal Halide, and High Pressure Sodium.

High Pressure Sodium (HPS) Lamp:
High Intensity Discharge light source which produces light by an electrical discharge sodium vapor operating at relatively high pressures and temperatures.

Hot Restart Time:
The time it takes a HID lamp to restart and reach 90% of its light output after going from on to off to on. Typical restart times are 1 to 2 minutes for High Pressure Sodium and 5 to 20 minutes for Metal Halide.

HPS Lamp (High Pressure Sodium Lamp):
A high intensity discharge lamp (HID) in which the light is produced by radiation from sodium vapor operating at a partial pressure of 100 Torr. Includes clear and di use coated lamps.

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IEC (International Electro-technical Committee):
An international independent standards organization. IEC standards are almost exclusively used in Europe and are adopted by many countries as their national standards for product safety and performance.

Ignitor (Starter):
A device used within the ballast circuit to generate high voltage electrical pulses needed to start High Pressure Sodium and some Metal Halide lamps.

Initial Lumens:
The measure of the amount of light a lamp produces after it has been operating 100 hours.

Input Voltage:
Voltage provided by a power line or power supply to the ballast or driver.

Input Watts:
Total power consumed by lamp and ballast when the lamp is operated at rated wattage.

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The unit of measure used to designate the color temperature of a light source.

Kilohertz (KHz):
One thousand Hertz (cycles per second).

Kilowatt Hour (kwh):
The standard of measure of electrical energy and the typical billing unit used by electrical utilities for electricity.

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LCL (Light Center Length):
The distance from the light center to a specified reference point on the lamp.

Radiant energy which can be sensed or seen by the human eye. Visible light is measured in lumens.

LPW (Lumens Per Watt):
See Efficacy

Lumen (lm):
SI unit of luminous flux emitted within a unit solid angle (1 steridian) by a point source of having a uniform luminous intensity of 1 candela.

Lumen Depreciation:
The decrease in lumen output of a light source over time. Also called Lumen Maintenance.

A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.

Lux (lx):
The SI unit of illuminance. One lux equals one lumen per square meter.

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Mean Lumens:
The average light output of a lamp over its life, usually determined by the light output at 40% of rated life.

Metal Halide Lamp:
A High Intensity Discharge (HID) lamp in which the major portion of light is produced by radiation of Metal Halides and their products of dissociation in combination with metallic vapors such as Mercury. Includes clear and phosphor coated lamps.

Mogul Base:
A large Edison Screw Base whose diameter is approximately 1.5 inches.

MOL (Maximum Overall Length):
The largest outside dimension of a lamp. Typically MOL is measured from the end of the lamp base to the top of the outer jacket.

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NEC (National Electric Code®):
A collection of electrical wiring specifications and standards developed by the National Fire Protection Association (NFPA), and adopted and used in all 50 states in the USA. This standard is accredited by ANSI and CSA.

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Open Circuit Voltage (OCV):
Voltage, as measured at the lamp socket (HID or CFL) or across the lamp holders (fluorescent) when the lamp is not present, generated by the ballast needed to start a lamp when power is turned on.

Operating Position:
The specific physical orientation in which lamps are designed to operate. (for example, Base Up = BU, Base Up or Down=BUD, Base Up to Horizontal=BUH, Base Down = BD, Horizontal = HOR, etc.)

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Compound used to completely surround and cover components of some magnetic and electronic ballasts in order to protect components, dampen sound, and dissipate heat.

Power Factor (PF):
The ratio of real power (watts) to apparent power VA (volts x amps). HID ballast power factor is classified in two categories, High (Pf ≥0.90), and Normal or Low, (Pf <0.90).

Probe Start:
Method of starting Mercury vapor and specific Metal Halide lamps in which an additional electrode at one end of the arc tube assists in lamps starting.

Pulse Start:
Method of starting High Pressure Sodium and specific Metal Halide lamps in which a high voltage starting pulse starts the lamps.

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A high heat resistant glass-like material manufactured from pure silica sand. Quartz is used for the arc tube in Mercury and many Metal Halide lamp types.

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Rated Life:
See Average Rated Life

Reduced Jacket:
A reduction in lamp bulb outer jacket size from the traditional standard size. Reduced jacket lamps are designed for special fixture applications and have generally shorter rated life.

RFI (Radio Frequency Interference):
Form of electromagnetic interference.

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Seasoning Time:
The time required for a new operating lamp to reach a state of equilibrium where the electrical, light level and color parameters stabilize. Typically, HID lamps obtain their rated performance after 100 hours of seasoning.

SI Unit:
The International System of Units universally abbreviated SI (from the French Le Systeme d’Unites).

A linear representation of the different radiant electromagnet wavelengths ranging from cosmic rays to radio waves.

System Efficacy:
Overall efficiency of the lamp/ballast system. System efficacy = total lamp lumens / system wattage.

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T12, T10, T8, T5:
Industry standard naming for a fluorescent lamp. (T = Tubular and the numbers that follow represent the diameter in 1/8 inch increments).

Thermal Protector:
A self resetting switch that disconnects power to the ballast if internal temperatures rise above the trip point – typically 105°C

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UL (Underwriters Laboratories):
Underwriters Laboratories Inc. is an independent, not-for-profit product safety testing and certification organization. UL has tested products for public safety for more than a century.

UV (Ultraviolet):
Radiant energy within the wavelengths of 100-400nm. UV energy is classified by IEC in three categories: UVA – 315 to 400 nm (“Black Light”), UVB – 280 to 315 nm (Bacterial Sterilization) and UVC – 100 to 280 nm (Ozone Producing).

Ultra Ace™ EN:
Converts a Mercury or Metal Halide system to High Pressure Sodium by simply changing the lamp. Meets Federal EPA TCLP requirements for non-hazardous waste.

Universal Operating Base Position:
Lamps that can be installed and operated in any position. The letter U commonly designates universal position operating lamps.

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Warm Up Time:
The time from the initial establishment of an arc to 90% of the steady state full light output of the lamp.

Watt (W):
A unit of power used to quantify the rate of doing work. In electrical calculations, one watt is the power produced by a current of 1 ampere across a potential difference of one volt. In addition, the radiant luminous flux of a lamp is also expressed in watts.

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