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26 Cards in this Set
- Front
- Back
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Visible light |
400-700 nanometers |
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Wavelength of colours |
Red longest Violet shortest Red is felt not seen by humans |
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Correlated colour Temperature |
5500 degrees K is daylight at noon |
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Colour rendering index |
Value indicating how well light source reproduces actual colour of object |
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Best CRI for true colour rendering |
CRI of 100 |
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Candela |
Unit of luminous intensity to quantify the brightness of a light source . Approximately amount of light from a single candle |
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Lumen |
Unit measurement of luminous Flux or quantity of light emitted by a light source |
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Lux |
Unit measurement of amount of illumination on a given area. One lux= one lumen per Metre squared |
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Efficacy |
Lumens per watt . How effective a light source is at producing desired light from specific amount of power |
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Light with best efficacy |
LPS has best efficacy |
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Incandescent lamps |
Tungsten filament Inert gas or vacuum Low efficacy Common for decorative, flood lighting and appliances Medium base is most common |
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Halogen lamps |
Halogen gas in quartz or alumonoscilate -produces better colour temp and better efficacy than standard incandescent -whiter less orange light - don't touch the quartz ...oil from skin reduces the life of the lamp -good for flood lighting to high intensity task lighting |
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Ballasts |
Establish arc . Limit current Magnetic or solid state Used as a transformer |
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Fluorescent lamps |
Linear or compact Most common electrodes are bi-pin |
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Integrated lamp |
Self ballasted |
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Electronic ballast |
Increases operating frequency of the lamp (magnetic stays the same at operating frequency) -improve power factor and reduce harmonic distortion |
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Ballasts / thermal protection |
If operates at 10 degrees above rated case temperature, it halves the life span of the ballast |
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Sound rating (ballast) |
Rated A to F A is quietest: home's offices F is loudest :street lights, factories |
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HID LAMPS |
Mercury vapor Metal halide High pressure sodium -street and parking lot lights -security lighting -gymnasiums |
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Metal halide |
Ceramic tube :good colour rendition Quartz tube : long life and low maintenance |
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Low pressure sodium |
Starter voltage creates arc at 3000V Takes about 3-4 minutes to be full |
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Lamp rating |
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Blackening of lamp |
Incandescent : it's almost dead Flourescent: loose connection |
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Lamp interchangeability |
Two basic factors -lamp base or pin design -manufacturer warning labels |
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Relamping |
Some metal halide lamps can replace : mercury vapor, HPS lamps HPS can replace mercury or metal halide lamps |
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Relamping practice |
-individual lamp -group relamping |
