Lighting Components Flashcards
A layer of light-sensitive cells along the back wall of the eye
Retina
Two types of photo receptors in the retina
Cones
Rods
High-light-level receptors
Cones
Low-light-level receptors
Rods
A flat, colored, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the center; kind of like a shutter mechanism
Iris
Protected by the iris from the bright light; a black, circular opening that allows light to pass to retina
Pupil
Adjusting to bright light; daylight vision, vision with sufficient illumination that the cones are active and hue is perceived
Photopic vision
Adjusting to dim light; night vision, the ability to see in reduced illumination (as in moonlight)
Scotopic vision
Three factors that influence the amount of light that will reflect off the object to the eye
Color
Texture
Surface
General type of color, texture, and surface that reflect more off the object to the eye
Light colors
Smooth textures
Shiny surfaces
Initial response and complete adaptation (in minutes) of an eye when shifting from low to high light levels
Less than a minute (initial)
7 to 12 minutes (full)
Complete adaptation (in minutes) of an eye when shifting from high to low levels
20 to 30 minutes
Measurement of illumination or quantity of light falling on a subject
Footcandle (fc)
European measurement of illumination or quantity of light falling on a subject
Lux
Approximate conversion of fc to lux
1 fc = 10.76 lux
Measurement of luminance or quantity of light reflected off the surface of an object; sees by the eye, rather than footcandles, making this measurement more important than footcandles
Footlambert (fl)
The amount of light reflecting off the surface of an object; takes into account the scattering of light as it reflects off a surface
Luminance
The relationship between luminances of an object and it’s background or between two areas in a landscape
Luminance contrast
The amount of light, seen by the eye, reflecting form the surface of an object; takes into account the state of adaptation of the eye
Brightness
A continuum of radiation, including all wavelengths of electric and magnetic radiation; much of the radiation is not seen by the human eye, and the portion that can be seen is called the “visible spectrum”
Electromagnetic spectrum
Basic parts of a lamp
Glass envelope or bulb Filament Electrodes or an arc tube Base Transformer (low-voltage incandescent lamp) Ballast (fluorescent/HID)
Type of glass which cannot withstand physical impact or temperature shock, and does not provide for maximum light output efficiency
Soda-lime or soft glass
Type of glass used for lamps rated for outdoor use in open fixtures; heat resistant and hard
Borosilicate glass
Typical incandescent lamp shape - S, F, G, T, PAR, R, MR, A
Straight side (S) Flame (F) Globular (G) Tubular (T) Parabolic aluminized reflector (PAR) Reflector (R) Multimirror reflector (MR) Arbitrary (A)
Typical HID lamp shape - BT, E, R
Bulbous tubular (BT)
Elliptical (E)
Reflector (R)
The number indicates the diameter of the lamp in eights of an inch at its widest point (ex. what is the measurement of the widest point of an R40?)
A reflector shape 40/8 or 5 inches at its widest point
Part of a lamp that connects it to the fixture socket and provides a path for electricity to reach the filament or arc tube
Base
The wire in an incandescent lamp that actually produces light; it heats up, producing light
Filament
Common material used today for filaments, which combines a high melting point and slow filament evaporation
Tungsten
A coating on the filament tube of some halogen lamps, which allows all the visible light to pass and redirects the infrared radiation back onto the filament
Dichroic coating
Three filament types
Straight (S)
Coiled coil (CC)
Coiled (C)
A filament type where there is more wire and is more closely spaced, which conserves heat and increases both efficacy and filament stability
Coiled filaments
Two basic categories of lamps
Filament lamps
Discharge lamps
Type of lamp that produces light by heating a tungsten filament in a vacuum- or gas-filled envelope
Filament lamps
Composed basically of a sealed glass containing a filament connected at its ends to the contact area in the base thereby completing an electric circuit
Incandescent lamps
Sometimes called quartz lamp, a lamp that offers a more balanced white color, higher efficiency, more compact size, longer life, and higher lumen maintenance than conventional incandescent lamps; have a halogen gas pumped in around the tungsten filament which picks up and redeposits the evaporated tungsten back onto the filament
Tungsten-halogen lamp
Most frequently used incandescent lamps
MR
PAR
R
An incandescent lamp that has a multifaceted-mirrored reflector surrounding a sub-miniature lamp; variations in the reflector permits many beamspread and wattage options in one lamp size; has a compact size which allows the fixture to be small; all are tungsten-halogen lamps, which provide improved color (over standard incandescent lamps); most are low voltage, and these are the ones used primarily for landscape
MR lamps
Type of lamp that creates light by sending an electric arc through a gas between two electrodes; all are more efficient than incandescent lamps at gross light output (lumen production); useful for floodlighting and accent lighting on large-scale commercial projects
Discharge lamps
An electrical device that provides a high-voltage pulse required to start a discharge lamp, then limits the amount of current to the lamp to prevent the lamp from drawing a destructive amount of current
Ballast
Four lamp families of high intensity discharged lamps, lamps that produce light by creating a relatively small electric arc (point sources); each of these lamp types requires a reflector to control its candlepower distribution, and all require an initial warm-up period when turned on, and if power is lost, require a cooling period before restriking their arc
Mercury vapor
Metal halide
High pressure sodium
Low pressure sodium
HID lamp that produce light by passing an electric arc through mercury vapor; produces light predominantly in the blue and green regions of the electromagnetic spectrum, and in the ultraviolet region; produces slightly fewer lumens per watt than the other HID lamps
Mercury vapor
HID lamp that produces light by passing an electric current through mercury gas, and scant quantities of specific combinations of metal halide; offer most balanced white color of all the HID sources; used for outdoor areas where color rendering is important; best choice for promoting plant growth; sensitive to voltage variation
Metal halide
Type of ballast that can aid in controlling color shift, can stabilize life, and prevent unwanted interruptions of light output
Electronic ballast
HID lamp that produces light by passing an electric arc through sodium vapor; produces most of its light in the yellow range of the spectrum. thus its color appears as a golden yellow; typically used only for lighting parking lots and freeways; the color it produces makes plants look dull and lifeless, and creates an eerie atmosphere
High pressure sodium
A lamp not technically grouped with the other discharge lamps; a monochromatic light source producing only yellow light; unable to render any colors well
Low pressure sodium
Consists of a tubular bulb with an electrode sealed into each end, and a combination of mercury (at low pressure) and argon (or a mixture of gases), which help in starting the lamp; the lamp walls are coated with fluorescent powders which are excited by the ultraviolet radiation to produce colors within the spectrum; temperature sensative
Fluorescent lamp
Three kinds of special fluorescent lamps that are used in landscape lighting
Jacketed
Aperture
Reflector types
A fluorescent lamp designed for low temperature operation
Jacketed (J)
Typical ballast used for most fluorescent lamps operated outdoors
Low-temperature ballast
A type of fluorescent lamp that has an internal layer of white powder between the phosphor and the tube
Reflector
Similar to reflector type of fluorescent lamp, except that it has a section of clear window area along the glass envelope
Aperture
A luminous tubing that runs at higher voltages, and produces less light per watt; has the ability to make very long pieces in any shape, and ability to produce many different colors; mainly for decorative purposes in landscape lighting; with high voltages, and their transformers are usually large and noisy
Cold cathode (including neon)
A combination of all colors of light; to produce it , a light source needs to have a relatively balanced quantities of all light waves through the electromagnetic spectrum
White light
The three specific, narrow bands of light wavelengths that the human eye is more sensitive to
Blue-violet
Pure green
Orange-red
A comparison of the color produced by a light source to a standard (blackbody) source heated to a particular temperature; measured in Kelvin (K), with low numbers referring to warm color and high numbers referring to cool color
Color temperature
Unit of light (or luminous flux)
Lumen
Unit of light intensity
Candlepower (CP) or candela (CI)
A devise that changes the voltage from the main power source to supply a lamp with either a lower or a higher voltage
Transformer
A device that serves as an attachment mechanism and an electrical connection box
Mounting box
Occurs when lighting equipment is exposed to oxygen, water, acids, and salts, especially those lacking of protective coatings or finishes
Corrosion
Refers to the disintegration proceeding at roughly the same rate over the entire surface of a metal exposed to a corrosive environment; primarily affects cast iron and mild steel; affect appearance, then eventually the structural integrity of a fixture; aluminum can sometimes suffer such corrosion, but further attack is suppressed by the resulting layer
Uniform corrosion
Type of corrosion that affects a small portion of the metal but can occur in several places on the metal surface at once; happens with most metals, including aluminum or stainless steel; results in worst damage than uniform corrosion; symptom of this is blistering paint
Pitting corrosion
Corrosion that occurs when a piece of equipment has a gully that will collect water or debris; takes place due to chemical reactions encouraged by trapped moisture; can occur in a crevice where two incompatible metals are in contact, or where a metal is in contact with a nonmetallic material such as plastic; occurs at screw joints
Crevice corrosion
A frequent type of corrosion in landscape lighting; occurs when moisture is held in and under a deposit on the metal
Deposit corrosion
Corrosion caused by the flow of liquid over a surface and is an issue to consider for underwater fixtures
Erosion corrosion
Corrosion that takes place when dissimilar metals are in contact and exposed to water or moisture
Bimetallic or galvanic corrosion
Corrosion that occurs where the current leaves the metal to enter the soil or water
Stray-current corrosion
Corrosion that occurs in metal alloys when components of the alloy corrode at different rates; most frequent in landscape lighting is the dezincification of brass; salt water and air encourage this type of corrosion
Selective or dealloying corrosion
Metals that contains iron, a reactive metal; with a tendency to lose electrons (forming ionic compounds), they have a higher corrosion potential than the opposite kind of metals
Ferrous
Family of metals that has a limited use in landscape lighting equipment; inexpensive, but has low have low structural strength and low corrosion resistance to high temperature; its primary use is for below-grade boxes, typically cast with thick walls and galvanized to retard the progression of corrosion
Cast iron
Metals that have limited use in landscape lighting equipment because the metal is expensive and difficult to work with; consists of a family of iron-based metals with varying amounts of additives; bit as thermally conductive as some other metals; generally susceptible to pitting, deposit, crevice, and stress cracking corrosion
Stainless steel and alloys
Type of stainless steel alloys that is generally used for lighting equipment; used as an inner lamp chamber for underground and underwater locations; nonmagnetic and nonporous
Austenitic
Less corrosive general types of metals, making them more useful in outdoor lighting equipment
Nonferrous metals and alloys
A material most outdoor lighting equipment are made of, due to low cost, ease of fabrication (forming, die and sand casting, and extruding), high strength, high heat conductivity, and the ability to form a corrosion-resistant film on its surface; finished either by paint or anodized finish
Aluminum and alloys
A relatively expensive material, normally chosen for aesthetic appearance; exhibits high thermal and eletrical conductivity, as well as strong resistance to corrosion in soil; susceptible to stress-induced cracking in the presence of ammonia
Copper and alloys
Metal often used for underwater fixtures and above-grade fixtures in very corrosive environments due to its structural strength and corrosion resistance; formed from a combination of copper with other metals or elements, including zinc and nickel
Brass
Process that refers to the selective leaching of zinc from the alloy, which weakens the metal significantly
Dezincification
Another materials used for submersible fixtures, typically a copper alloy with tin; has better corrosion resistance and not as affected by stress corrosion cracking; normally cast
Bronze
Metal primarily used as an additive to or coating on other metals to increase their corrosion resistance; has an extremely high resistance to atmospheric corrosion
Zinc
Primarily used in lenses; produced froma mixture of silica, sand, and oxides (including soda, lime, magnesia, alumina, lead oxide, and boron oxide) fused together at high temperature
Glass
Shape of lenses that discourages debris collection
Domed shape
Form of lenses that can direct light
Ridges
Type of lenses that spread the brightness of a lamp
Opal glass lenses
Sand-blasted lenses
Two basic types of plastic class of materials
Thermoplastics
Thermosets
Type of plastic that becomes fluid at elevated temperatures, which allows reshaping
Thermoplastic
Type of plastic that will not flow at elevated temperatures, they char or burn; cannot be recycled
Thermosets
Type of plastic normally used for fixture housing, junction boxes, and other containers; all nonflammable with good corrosion and UV resistance
Polyvinyl chloride (PVC)
A form of polystyrene offering excellent toughness with good strength, stiffness, and high corrosion resistance; can be formed, extruded, and molded; many do are not UV-resistant; should not be used when a watertight seal to the lamp compartment is required
Acrylonitrile-Butadiene-Styrene (ABS)
A resin with low shrinkage rate useful for adhering and potting; provides excellent adhesion to metals, and other materials along with chemical resistance and waterproofing characteristics; typically used in the potting of antisyphon chambers and to isolate electrical wires, thus prevents wicking
Epoxy
Available as pastes and greases offering superior thermal stability can be used for lubrication to provide corrosion protection of sockets and threads; as adhesive gasket material, it has flexibility under pressure; high heat resistance and low moisture absorption
Silicone
Offers extreme clarity, good light transmission, impact resistance, and high UV resistance for lens use; with poor coordination of lamp wattage and housing size, yellowing and cracking of the lens can occur; inexpensive types break and scratch easily, and are temperature sensitive
Polymethyl methacrylate (acrylic)
Used for lenses, a type of plastic that offers high impact strength, rigidity, and stability up to 240 F, good clarity, and UV-stabilized forms hold well in outdoor environments
Polycarbonate (lexan)
Have good weathering, aging, and good heat properties; does not hold up as well as other gasket materials in lighting fixtures due to high heat; food for nonheat situations such as gasketing in underwater fixtures; inexpensive, but has a lower temperature range, and less ability to retain its original shape than PVC
Ethylene propylene diene monomer (EPDM) rubber
A finish that deposits oxygen on the metal surface, which combines chemically with the aluminum; a process entails a series of baths for cleaning and pretreating; provides a good seal by penetrating the pores and reducing their openings; typically a clear finish, but color can be added; sensitive to pollution and any contact with an acid
Anodizing
Type of anodizing processes that uses either organic dyes or inorganic dyes; does not include corrosion protections , and should not be used for outdoor lighting equipment
Clear anodize and dye
Type of anodizing processes that includes several classes of anodizing: commercial, class II, and class I; only class I has a thick enough coating and seal to withstand outdoor conditions
Two-step or two-step electrolytic
Type of anodizing that produces a harder finish but costs more than two-step; works only on a few aluminum alloys
Duranodic (alcoa) orKalcolor (kaiser
Paint finish that consists of a powder resin heated to a temperature between 375 F and 400 F to form a strong, durable, but somewhat porous finish; requires a conversion coating to ensure long-term performance and corrosion protection
Powder coat
Three types of conversion coatings
Chromate
Phosphate
Oxide
A type of polyester that is goof for outdoor lighting equipment; combines a small amount of epoxy-curing resin with the polyester resin to provide additional corrosion and solvent resistance; does not chalk, resistant to heat and UV and resists overbake, unlike epoxy
Triglycidal isocyanurate (TGIC)
Both a natural aging process and a treatment applied to brass and copper, produces a green or bluish appearance called patina; the process depends on the formulation of the chemical compound applied to the metal surface, as well as controlled humidity and temperature, to induce the reaction
Verdigris or verdi green
Intensity of light required for casual work, as in conferencing, interviewing, and inactive filing
10-30 fc
Intensity of light required for moderate work, as in intermittent filing and general clerical work
30-50 fc
Intensity of light required for prolonged work, as in active filing, index referencing, and mail sorting
50-100 fc
Intensity of light required for precision work, as in accounting, auditing, tabulating, bookkeeping, business machine opertation, reading poor reproductions, and rough layout drafting
100-150 fc
Intensity of light required for fine precision work, as in cartography, designing, and detail drafting
150-200 fc
Loss of light when light rays strikes or traverses any medium
Absorption
The ratio oflight absorbed by a material to the light falling
Absorption factor orabsorptance
A beam of light is reflected diffusely, that is, its ray is scattered in alldirections, if it strikes a rough or matte surface
Diffuse reflection
A beam of light is specularly reflected when a light ray striking ashiny or glossy surface at an angle of incidence is reflected as the same beam with equal angle of reflection
Specular reflection
The ratio of light reflected by a surfaceto the light falling upon it
Reflectance or reflection factor
The passage of light through a medium when light falls upon a transparent material; light is “refracted” (bent) as it passes through the material but emerges at the same angle that it entered
Transmission
The ratio of light transmitted tolight striking the surface
Transmittance or transmission factor
Directional lighting to emphasize a space or an object
Accent lighting
A fixture producing concentrated direct lighting from a single bulb; may be recessed in or mounted on the ceiling
Down light
A term often applied to a can-type of recessed incandescent downlight
High hat
Recessed or semi-recessed lighting unit with a rotating spherical element that may be turned to project light in any direction
Eye ball
A tubular fluorescent lamp with a disc base at each end
Lumiline
A false ceiling of diffusing material with light sources mountedabove
Luminance ceiling
A device which changes either amount or color, or both. of light passing through it
Filter
A device to control the amount of light by reducing the voltage or the current
Dimmer or rayostat
The quantitative measure of the electric-energy storage capability of acapacitor; usually measured in farads or microfarads
Capacitance
An electric component which consists of conducting plates insulated from each other by a layer of dielectric material; introduces capacitance into a circuit.
Capacitator
