Lighting Flashcards
What are the 3 main types of lighting?
1- incandescent
2- discharge
3- LED
What type of lighting is tungsten filament lamps?
Incandescent
What type of light is produced by tungsten filament lamps?
Clear white light
What trait does tungsten filament lamp?(hint. Disadvantage)
Poor efficacy
What type of lighting is tungsten halogen lamps?
Incandescent
Why is halogen added to the tungsten halogen lamps?
To strop the tungsten evaporating
What impact does the use of quartz glass have on tungsten halogen lamps?
The glass is weakened by human touch allowing the halogen gas to escape reducing the life expectancy of the lamp
Incandescent lamps describe which two lamp types
Tungsten filament lamp
Tungsten halogen lamp
How does discharge lighting work?
Work by discharging voltage across a gas filled tube, thus ionising the gas which reducing the resistance. This allows for lower voltage to maintain the ionisation
This type of lighting uses control gear like chokes to maintain low lamp currnts
What are the 3 types of discharge lighting?
1- low pressure mercury lamps
2- high pressure mercury
3- metal halide lamps
What type of light is produced by low pressure mercury lamps?
Ultraviolet light which is absorbed by the phosphor coating creating the light
What applications can low pressure mercury lamps be used in?
Domestic
Offices
Shops
Workshops
What colour of lighting is produced by high pressure mercury?
White light with a blue tinge
What are the common applications used for high pressure mercury lamps?
Factory lighting
Car park lighting
Street lighting
CCTV
Any application that requires good colour correction
High pressure mercury is used for cctv! Why?
Good colour correction
What is the main difference between metal halide and high pressure mercury lighting?
Metal halide lamps use halides instead of mercury
Why are metal halide lamps used for security and sports arena lighting?
Good colour rendering and efficacy
What applications are metal halides used for?
Sports arenas
Security
General amenity
How do LED lights work?
P-N junction diodes emits light when energised
What type of light is produced by LEDS?
White light produced by combining red green and blue lights
What are the advantages of LED lighting?
6x greater efficacy
20000 hours of life
Do not emit UV or IR so can be used around heat or UV sensitive materials
What are the common applications of LED lighting?
Indication
Decoration
Small and large lamps
Signage
In areas sensitive to heat or UV
What is the equation for lighting design?
F= E X A / CU X MF
What does F stand for in the lighting design equation?
Luminous flux (lm)
What does the E STAND FOR IN THE LIGHTING DESIGN EQUATION?
Illuminance level required (Lux)
What does the A stand for in the lighting design equation?
Area
What does CU stand for in the lighting equation?
Coefficient of utilisation
What does MF stand for in the lighting design equation?
Maintenance factor
