Lighting Glossary

Lamp lightbulb (not light fitting)

Fitting the appliance the lamp fits into, often informally called a lamp, eg tablelamp.

Luminaire same as fitting

CRI Colour rendering index. How well light renders colours. One measure of light quality. 100 is perfect CRI, 50 is poor. CRI is not the only determinant of colour rendition, CCT matters too.

CCT Colour temperature. A measure of light's perceived warmth or coldness. 3000K appears warm, 4500K appears cold, containing a higher percentage of blue light.

LED Light emitting Diode. A small low power solid state light source.

Lumen Quantity of light output

Ballast current control device needed to run fluorescent, CFL and discharge lamps. Built into the fitting, or in the case of most CFLs, ballast and lamp are in one lamp-replacement unit.

Cap the electrical connection end of a lamp.

BC Bayonet cap, push and twist connection

ES Edison screw cap

Efficacy output in lumens per watt. From a non-technical point of view can be considered as efficiency, although this is not strictly accurate.

Bipin 2 pin bulb base used on fluorescent tubes and some halogen lamps

Phosphor Coating inside fluorescent tubes that transforms UV into visible light. See also: halophosphate, triphosphor

Halophosphate One of the 2 families of phosphorescent materials used in fluorescent tubes. Light output falls over time.

Triphosphor The more recent of the 2 families of phosphorescent materials used in fluorescent tubes. Slightly higher efficiency, less fall in light output over time.

GLS General Lighting Service, the traditional filament light bulb.

Rough service lamp Shock and vibration resistant filament lamp

CFL Compact Fluorescent Lamp.

LV Low Voltage

Starter small device that works with a magnetic ballast to start the lamp. Used with fluorescent and some discharge lamps. Starters may be glowstart, electronic, or rarely thermal or a manual switch.

BL blacklight produces UVA and blue/violet light

BLB blacklight blue. Produces UVA only. The dark blue glass filters out nearly all the visible light.

Germicidal lamp produces short wavelength germicidal UV. Damaging to eyes, kills bacteria & erases eproms. Never use these in insect killers or for parties. See UVC.

Uplighter Fitting sending most light upwards

Plaster Uplighter Plaster half bowl uplighter. Suffers various design defects.

Downlighter fitting sending most light downwards

Spotlight reflector lamp throwing most light out over a limited arc, producing a pool of light

Floodlight produces a wide spread of light. Note some floodlights may look like spotlights, with a built in reflector.

Dimmer A device for reducing lamp output. A popular description is 'a device for turning down the efficieny of light bulbs.' Most dimmers are incompatible with most types of lighting other than filament & mains halogen.

Shelf fitting The (normally fluorescent) fitting is mounted on its side on a shelf so the lamp is concealed from view. The fitting however remains visible.

Trough Fitting The lamp is partially enclosed in a trough which conceals it from view. The fitting is also concealed.

Choke Magnetic ballast used in glowstart fluorescent fittings.

Capacitor Component used for power factor correction with magnetic ballasts.

Capacitor Ballast A type of ballast used to eliminate strobing in workshops. Capacitor ballasts generally produces shorter tube life in most cases

Halogen Lamp Type of filament lamp with better efficacy than traditional filament lamps. Contains bromine or iodine. Very high capsule temperature.

Sodium lamp Yellow lamps used for streetlighting

Mercury Discharge Lamp Ice white lamps used for street lighting, very energy efficient

Metal Halide Lamp A high efficiency white discharge lamp

SES small edison screw, a miniature lamp base

E14 a miniature screw fitting lamp base

E27 27mm Screw in base, aka ES

E40 Giant screw base, used with some discharge lamps

Suntan Lamp Lamp producing high levels of UVA. Protective goggles must be used.

UVA, UVB, UVC The three frequency bands of ultraviolet. UVA is used for suntanning, blacklights and insect killers. Outdoor levels of UVA cause skin wrinkling and some cancers. UVB causes sunburn and cancers. UVC is germicidal and destructive to human tissue, and is not present in sunlight on earth. The wavelengths are approx:

• UVA: 320-400nm
• UVB: 290-320nm
• UVC: 200-290nm
• Around 2/3 of melanomas and 90% of basal and squamous cell skin cancers are currently attributed to UV exposure.

Daylight

Warm White 2700K

Cool White

T8, T12 T8 are 1" diameter fluorescent tubes, T12 are the older 1.5" diameter ones. T8s have mostly replaced T12s. T8s work happily in older T12 fittings.

PAR Parabolic Aluminised Reflector, spotlight.

HID High Intensity Discharge, aka metal halide lamp.

See Also

• Lighting
• Fluorescent Lighting
• LEDs
• Halogen Lighting
• Rewiring Tips