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HELPFUL TERMINOLOGY ON LAMPS |
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Voltage |
The voltage of a circuit is the electrical pressure it gives,
in an indandescent lamp voltage designated the supply voltage
to which the lamp should be connected. In other lamps it may
refer to operating voltage of a lighted arc discharge lamp. |
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Wattage |
Unit used to measure power consumption
of lamp. |
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Candlepower |
A term used for the luminous
intensity of a light source. |
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Average Rated Life |
The statistical average of lamp
under controlled laboratory conditions. |
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Color Temperature |
Measured in Kelvins, it is the
measure of color of light, not actual temperature. |
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Light |
The term generally applied to
the visible energy from a source, measured in lumens or candlepower. |
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Light Centre Length
(LCL) |
The distance from a reference
point on the lamp base to the centre of the light source. |
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Lumens |
The amount of light emitted by
a bulb. |
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Luminance or Brightness |
The light emitted, transmitted
or reflected from a unit area of the source of surface. |
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Halogen |
Halogen lamps, in addition to
being gas filled have a gaseous halogen compound added to the
gas fill. Its purpose is to prevent any blackening of the bulb
by returning evaporated tungsten back to the filament through
a halogen cycle. The higher molecular weight gas and higher
fill pressure permits operation at higher temperatures than
regular gas filled lamps. For the same life, halogen lamps have
the highest efficiency. |
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Vacuum |
The incandescent tungsten filament
must be protected from exposure to the atmosphere, this achieved
in a vacuum lamp
by processing the lamp so that a vacuum exists
inside the glass envelope. |
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Gas Filled |
Gas filled lamps use an inert
gas to protect the filament during operation. The use of fill
gas reduces the net rate of tungsten evaporation by several
orders of magnitude thus the filament can be operated in higher
temperatures making the lamps more efficient than vacuum lamps. |