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P
PEAK DEMAND
a utility customer's maximum load. For purposes of calculating utility cost,
peak demand is generally based on the maximum monthly demand, where demand
is measured as an average over a time interval, usually 15 or 30 minutes.
PHOSPHORS
chemical compounds that are used to coat the inside of fluorescent and some
HID lamps.
PHOTOMETRIC DATA / PHOTOMETRIC REPORT
the lighting performance of a luminair may be measured either by the
manufacturer or by an independent testing laboratory. The results of these
measurements are produced in a photometric report, which often becomes part
of the catalog description of that luminair.
PLENUM
The space between the ceiling and the floor or roof above.
POTENTIOMETER
Intensity control device used in dimmers. May be either a rotary knob or
linear slide type element. A variable resistor used in analog control.
PRISMATIC LENS
Prismatic lenses incorporate a pattern of small prisms or other refractive
elements to reduce the luminance of the luminair and inhibit direct glare.
PARCANS
Lighting fixture that accepts parabolic type lamps that cast an oval beam of
light.
PAR SPOT
Spotlight that accepts spot or flood PAR lamps.
PAR LAMP
Parabolic type lamp available in various spread patterns & wattages.
PIGTAIL
Short cable affixed to a circuit box with a female connector attached.
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