HID Glossary of Terms
ADX - Aqua color ~ 509nm
ANSI - American National Standards Institute
Arc Tube - A sealed quartz or ceramic tube where light is generated.
AQ - Aquarium Light
Ballast - A coil or coils that regulate power going to the bulb/s.
Ballast Factor - associated with fluorescent ballasts.
BD - Burn Base Down only
BL / BDX - Black light or Blue color ~ 460nm (sometimes called 20,000K)
BT - Blown tubular (Bulb shape)
BU - Burn Base Up only
Burning Position - The position the bulb is designed to operate.
C - Coated (diffuse) bulb
Cold Start - When power is first applied to a light bulb.
Color Rendering Index (CRI) - The ability to render colors to a standard.
Constant Wattage Autotransformer (CWA) - A lead style ballast with the capacitor in series with the lamp.
Constant Wattage Isolated (CWI) - Same as CWA but the coils are isolated from each other.
Control Gear - European term for ballast system (ballast/cap/ignitor)
Controlled Current Reactor - A reactor ballast but the capacitor is carefully selected to minimize open circuit current. Replaces CWA type ballasts.
Correlated Color Temperature (CCT) - The perceived color of light expressed in Kelvin (K)
Current Crest Factor - The ratio of the peak to the rms value of lamp current.
D - Diffuse or Daylight
DE - Double - Ended (HQI) bulb
DL - Daylight / Brilliant white color temperature.
DX - Deluxe White (mercury vapor) ~ 3900K
Economic Life - The number of hours when it is ideal to replace the bulb/s.
ED - Bulb shape and diameter in 1/8 inches. (ED28 = 3.5 in. diameter )
ESB - Energy Saving Ballast
Fc2 - Double- ended bulb socket/base
G12 - BiPin metal halide bulb socket/base
Getter - Catches ions inside a light bulb. This improves the light quality.
GR / GDX - Green ~ 535nm
HBD - Horizontal to Base Down operating position.
HBU - Horizontal to Base Up operating position.
Hg - Mercury
HID - High Intensity Discharge bulb
HIE - E27 or E40 European elliptical bulb (enclosed fixture required)
High Power Factor (HPF) - A ballast designed with the input power factor so it is not less than 90 %.
High Reactance Autotransformer (HX-NPF/HX-HPF) - Similar to the Reactor (R) but has an extra coil to transform Voltage.
HIPE - E27 or E40 European elliptical bulb (open fixture rated)
HIT - European Tubular bulb shape (enclosed fixture required)
Hot Restart or Restrike - When a power interruption has occurred and the time it takes to relight.
HOR - Horizontal
HPI - European Metal Halide
HPL - European Mercury Vapor
HPS - High Pressure Sodium
HQI - Metal halide bulbs with a high CRI (enclosed fixture is usually required) and/or DE/SE European lamps
HQL - European mercury vapor
Ignitor (starter) - Generates voltage pulses to a lamp for starting.
Initial Lumens - The light output of a bulb at 100 hours of operation.
Input Voltage at Lamp Dropout - The lowest amount of supply voltage when the lamp extinguishes.
Lag - A ballast exhibiting primarily inductive electrical characteristics.
Lamp Voltage - The voltage the bulb operates at (burning voltage).
Lamp Wattage - The power consumed after warm-up.
Lead Ballast - A ballast having a leading current. (CWA/CWI)
Light Center Length (LCL) - The distance from the base of the bulb to the center.
LPS - Low Pressure Sodium
Lumens - A measurement of light output.
Lumen Maintenance - The lumen output at a given point or at a percentage of its life.
Lumens Per Watt (LPW) - The amount of lumens per watt. This tells you how efficient a bulb is.
Maximum Overall Length (MOL) - The distance from the top of the bulb to the bottom.
Mean Lumens - The amount of light output at a given point.
Medium Base (MED) - E26 or E27 (E27 Export)
MG - Magenta
MH - Metal Halide
Mogul Base (MOG) - E39 or E40 (E40 Export)
MV - Mercury Vapor
nm - Nanometers (color wavelength)
Normal Power Factor (NPF) - A ballast that does not have any correcting of the input power.
O - Open rated bulb
Open Circuit Current (Line) - The RMS current from a ballast.
Open Circuit Voltage (OCV) - The RMS voltage when not loaded.
Operating Current (Line) - The RMS current through the input of a ballast.
Operating Voltage - Lamp voltage
OR - Orange color
Par - Parabolic reflector lamp
PDX - Pink color ~ 635nm
Peak Lead Ballast - A ballast that has a high peaked circuit voltage wave shape and operates with a capacitor in series with the bulb.
Position Oriented Mogul Base - Used for position orientated horizontal bulbs.
Power Factor - The ballast input power divided by the product of the ballast supply and ballast supply current.
Probe Start - A bulb that uses a starting electrode to start the bulb.
PS - Pulse Start bulb
Pulse Start/ Pulse Arc - A bulb that uses an ignitor + ballast
R - R warning: This lamp can cause serious skin burn and eye inflammation from short wave ultraviolet radiation if outer bulb is broken or punctured. Do not use where people remain more than a few minutes unless adequate shielding or other safety precautions are used.
R40 - Reflector lamp - 5 in. diameter
Rated Life - The operating burning hours of a bulb.
Rated Supply Voltage - The voltage a ballast is designed for.
Reactor - One coil connected in series with the bulb.
Regulated Lag - Uses three coils to provide the highest regulation to the lamp.
Restrike - To restart the arc in a bulb.
RSC - A double-ended socket/base (RX7s)
RX7s - A double-ended socket/base
SE- Single Ended lamp
Short Circuit Current - The current of a ballast when the output is shorted.
Shroud - A glass tube around the arc tube (not outer bulb) to protect the outer bulb from breaking if an arc tube rupture occurs.
SON - European High Pressure Sodium
SOX/SOX-E - Low Pressure Sodium
Starter / Starting Aid - Same as Ignitor
Starting Current - The measure of input current at startup (5 - 15 sec.)
Starting Pulse - A high voltage pulse to aid starting of some lamps.
Sustaining Voltage - The instantaneous voltage available to a lamp from the ballast at the time the lamp current passes through zero.
System Wattage - The power going to the input of the ballast. (Ballast + Lamp watts)
T - Tubular shape
Universal (U) - Universal operating position
V - Vertical
Warm Up Time - The amount of time the lamp takes to light to 90% from start up.
Watts - A measurement of power being used or emitted by a lamp each second.
WDX - Warm White Deluxe (mercury vapor) ~ 3300K
White SON - White High Pressure Sodium
Note: Some terms depend on manufacturer
Text by: Paul Erik Hirvonen
