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