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XII.9
Glossary
P
PAR Lamp
PAR is an acronym for parabolic aluminized
reflector. A PAR lamp, which may utilize either
an incandescent filament , a halogen filament
tube or a HID arc tube, is a precision pressed-
glass reflector lamp. PAR lamps rely on both
the internal reflector and prisms in the lens for
control of the light beam.
Parallel Lamp Operation/Parallel Wiring
Refers to ballasts that employ multiple output
current paths from a single ballast to allow
lamps to operate independent of one another,
allowing other lamps operated by the ballast
to remain lit should companion lamp(s) fail (see
SERIES LAMP OPERATION).
PCB (Polychlorinated Biphenyls)
Chemical pollutant formerly used in ballast
capacitors that were part of ballasts. It is now
illegal to use PCBs and most such ballasts have
been replaced over time.
Peak Wavelength
The maximum wavelength of an LED.
Phosphor
An inorganic chemical compound processed
into a powder and deposited on the inner glass
surface of fluorescent tubes and some mercury
and metal-halide lamp bulbs. Phosphors are
designed to absorb short wavelength ultraviolet
radiation and to transform and emit it as visible
light (See FLUORESCENCE). Phosphors are
also used in LED devices to create white light
when used in combination with LEDs of certain
wavelengths.
Photometry
The measurement of light and related
quantities.
Photopic
Vision for which the cones in the eye are
responsible; typically at high brightness and
in the foveal or central region (See SCOTOPIC ,
FOVEA, FOVEAL VISON).
Plug-In
(See CFL).
Potting
Material used to completely surround and cover
components of some magnetic and electronic
ballasts. Potting compound fulfills functions of
protecting components, dampening sound, and
dissipating heat .
Power Factor (PF)
A measure of the phase difference between
voltage and current drawn by an electrical
device, such as a ballast or motor. Power
factors can range from 0 to 1.0, with 1.0 being
ideal. Power factor is sometimes expressed
as a percent . Incandescent lamps have
power factors close to 1.0 because they are
simple “resistive” loads. The power factor of a
fluorescent and HID lamp system is determined
by the ballast used. “High” power factor
usually means a rating of 0.9 or greater. Power
companies may penalize users for using low
power factor devices.
Power Factor Corrected
Ballasts that incorporate a means of Power
Factor Correction yielding power factor of 90%
or greater.
Precise™
The GE trade name for the compact MR-16 and
MR-11 low-voltage halogen dichroic cool beam
reflectorized spot and flood lamps.
Preheat Circuit
A type of fluorescent lamp-ballast circuit
used with the first commercial fluorescent
lamp products. A push button or automatic
switch is used to preheat the lamp cathodes
to a glow state. Starting the lamp can then be
accomplished using simple “choke” or reactor
ballasts.
Product Code
It is important to use this five-digit code when
ordering to ensure that you receive the exact
product you require.
Programmed Rapid Start
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 preheating 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.
Pulse Start
An HID ballast with a high voltage ignitor to
start the lamp.
Q
Quad
Generally refers to a compact fluorescent lamp
containing 4 U-shaped tubes.
Quartz
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.
Quartz-Halogen Lamp
(See HALOGEN LAMPS).
Quartzline®
A GE registered trademark term for some types
of halogen lamps.
R
Radiation
A general term for the release of energy in a
“wave” or “ray” form. All light is radiant energy
or radiation, as is heat , UV, microwaves, radio
waves, etc.
Rapid Start
Lamp starting method in which lamp filaments
are heated while open circuit voltage (OCV) is
applied to facilitate lamp ignition. A Rapid Start
fluorescent lamp has two pins at each end
connected to the filament . Some rapid start
lamps may be instant-started without filament
heat , for example, the F32T8 lamp.
Rapid Start Circuit
A fluorescent lamp-ballast circuit that utilizes
continuous cathode heating, while the system
is energized, to start and maintain lamp light
output at efficient levels. Rapid start ballasts
may be either electromagnetic, electronic
or of hybrid designs. Full-range fluorescent
lamp dimming is only possible with rapid start
systems (See INSTANT START).
Rated Lamp Life
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 colour shift and also on the need to
reduce lamp replacement costs (See GROUP
RELAMPING).