Lighting Flashcards by Dan Smith

Luminous efficacy

How well a light source produces visible light.

How well did you know this?

Not at all

Perfectly

Luminous efficacy of incandescence/ LED / low pressure sodium

Incandescent = 22Lm (worst)
Low pressure sodium 200 (best
LED = 150 lumins

How well did you know this?

Not at all

Perfectly

Two types of light measurments

1: The total quantity of light output (lumin)
2: the quality of light (Lux)

How well did you know this?

Not at all

Perfectly

Explain luminous flux

The quantity of light output from source. Measured in lumen (Lm)

How well did you know this?

Not at all

Perfectly

Explain flux density

The density of light flux measured on a surface. Measured in lux (Lx)

How well did you know this?

Not at all

Perfectly

Two lighting equations

1:Inverse square law
2:Cosine law of incidence

How well did you know this?

Not at all

Perfectly

Explain inverse square law

Illumination is inversely proportional to the square distance between source and surface. Light gets dimmer further away you go in distance

E = I/d2

E = lux
I= light intensity
D= distance squared

How well did you know this?

Not at all

Perfectly

Explain cosine law

E = I/d2 x cos

Illumination changes with angle change

How well did you know this?

Not at all

Perfectly

Lux = intensity in lumens/distance in metre squared meaning?

Double the distance from light source means 1/4 of the illumination on surface

How well did you know this?

Not at all

Perfectly

Lumen

Amount of visible light seen from a source

How well did you know this?

Not at all

Perfectly

Lumen

Amount of visible light seen from a source

How well did you know this?

Not at all

Perfectly

What are luminaries

Complete light fixture ( housing, ballast, wiring etc)

How well did you know this?

Not at all

Perfectly

Two types of light loss

1: lumen depreciation (bulb deteriorates over time and gets less intense the older)

2: luminaire dirt depreciation
(The accumulation of dirt can cause loss of 30% or more) can be avoided by ventilation or cleaning

How well did you know this?

Not at all

Perfectly

What part of eye does light enter

Cornea

How well did you know this?

Not at all

Perfectly

Light passed through _______ and then strikes the ______ to form optical image

Passes through LENS and strikes RETINA

How well did you know this?

Not at all

Perfectly

What two nerves does retina contain

Rods: provides sensitivity to light

Cones: allows us to see detail and colour

How well did you know this?

Not at all

Perfectly

4 Factors affecting vision

1: size ( larger object easier to see)
2: brightness
3: contrast ( different brightness)
4: time ( longer visible more detail seen)

How well did you know this?

Not at all

Perfectly

What wavelength can human eye detect

Between 380nm - 760 nm

Nm= nano metres

How well did you know this?

Not at all

Perfectly

Most sensitive wavelength for human eye

555nm (yellow / green)

How well did you know this?

Not at all

Perfectly

What are the 3 primary colours

Green red and blue

How well did you know this?

Not at all

Perfectly

What is another word for colour temperature

Chromaticity

How well did you know this?

Not at all

Perfectly

What is colour temperature measured in?

Degree Kelvin (k)

How well did you know this?

Not at all

Perfectly

What is a low temp measured at?

Bellow 3000k lower kelvin = warmer colour (yellow/red)

How well did you know this?

Not at all

Perfectly

What is high temp measured above in kelvin?

Above 4000k = cool colour

Higher k = whiter light (blue / white )

How well did you know this?

Not at all

Perfectly

Explain CRI

Colour rendering index: a measurement of how natural colors render under an artificial white light source when compared with sunlight. The index is measured from 0-100, with a perfect 100 indicating that colors of objects under the light source appear the same as they would under natural sunlight.

Does high CRI mean less or more colour distortion

Higher the CRI = the less distorted and more like what we would see under natural sunlight

Rated life of lamp is determined by what?

By 50% lamp failures under normal conditions

Advantages of incandescent light

Cheaper Colour appears more natural

What is incandescent filament lights made of

Tungsten as has a 3419c melting temperature

Higher filament temp = lifespan reduced or increased?

Reduced - a 100w lightbulb at 120v will Burn dimmer than the same lightbulb at 130v. Will have longer lifespan at 120v

Lower filament temp means?

Less light produced but longer lifespan

What gas is in an incandescent and why?

Inert gas (argon) it is used to stop evaporation of tungsten filament when it gets hot

Incandescent have a positive temp coefficient why?

When cold draws more amps. When it warms up resistance increases and less amps flow

What does code and number mean on bulbs

Letter = shape/style of bulb Number = diameter of face of bulb in inches 1/8th inch

Describe inrush current and why does it blow out bulbs

A surge of current when switching light on as the cold resistance is very minimal allows a lot of current to pass. Up to 20x more amps flow

What are tungsten halogen lamps

1:Made of quartz as quartz can withstand high temp. 2:Burns very hot and bright ex. Car headlight/spotlight/floodlights 3: cannot touch with bare hands as oil on skin damage quartz surface

What is lifespan of tungsten halogen lamps

2500-3000 hours usually MR16 12volts and 10-50watts

Advantages of LED Lights

1: low power consumption 2: no early installation failures 3: resistant to shock and vibration 4: instant start (no warming up) 5:lifespan of 50,000 hours

Disadvantage of LED

1:More expensive 2:heat sensitive excess heat effects lifespan 3:not all dimmable 4:good CRI but not as good as incandescent

Grounded conductor =

Neutral

Ungrounded conductor =

Hot (black or red)

What is efficacy

Light Source efficiency in turning electrical energy into light energy= led more efficient lower watt and more light

What are mogul bases used for

Wattage over 300w or higher

Screw shell MUST be attached to neutral- true or false

True

What is the most common base used for lights

Edison screw base

Most used lamp sizes

Candelabra, intermediate, medium , mogul

What plans are used commonly in Electrical construction prints to show the power distribution

Single line drawings

Single line only shows supply side no load. True or false

True- only supply on top line

Riser diagrams are used more than any other in electrical construction

True

How many views in orthographic projection (max)

Max of 6 views. Usually 3 top,front,side

Orthographic projections are drawn to scale. T-F

True

What is most common use for orthographic projections in electrical

Machines and equipment in from of detail and assembly drawings

Min rated wiring temperature

90degree nmd90

To prevent induction heating - all conductors of same circuit must be in same raceway t/f

True. Must be in same metal raceway

Max voltage to code CEC

150v and must use #8-32 machine screw

Lamp life / output. Lamp life is inversely proportional to voltage. T/f

True

Power light output is proportional to voltage t/f

True

1 watt = how many lumen

683

Melting point of tungsten and quartz

3500c tungsten 1700c quartz

Switch/relay will operate EXTRA LOW VOLTAGE 24V or less T/F

True

What screws are used in lighting box

#8 - 32 screws

What is used in fluorescent lighting tube to assist current flow

Argon gas

What is used to transform uv into visible light

Phosphor coating

Lighting Flashcards

(63 cards)