MENU

Glossary of Terms

Commonly used words in lighting

AMPERE (AMP)

– The unit for measuring rate of flow of electrical current – Current (Amps) = Power (Watts) / Voltage (Volts)

BALLAST

– A device used to operate fluorescent or high intensity discharge (HID) by regulating the lamp voltage.

BEAM ANGLE

– The width or angle of light emitted from the lamp/luminaire.

BAYONETE CAP (BC)

– A common lamp cap found on many lamps in domestic use in South Africa. The lamp has two small pins that protrude from the base, these are inserted into the lamp holder and lock the lamp in place as it is rotated. B14 and B22 are the most common types.

CANDELA (cd)

– The international (SI) unit for luminous intensity. The intensity of a light source in a specific direction

CHIP

– The LED Chip is the light source

CHIP ON BOARD (COB)

– The latest generation of LED light source. Many small LED chips are incorporated in one packaged light source to provide a more efficient solution that can be combined with a lense and/or reflector to maximise the light distribution

CONVENTIONAL CONTROL GEAR (CCG)

– Control gear used to run a lamp, typically consisting of a ballast, ignitor and capacitor

COLOUR APPEARANCE

– A term used to describe how “white” the emitted light looks. Commonly, warm neutral, cool and daylight are used to categorise.

COLOUR RENDERING INDEX (CRI)

– A measure of the degree of colour shift objects undergo when illuminated by the light source as compared with those same objects when illuminated by a reference source of comparable colour temperature. Expressed on a scale of 1 to 100 where 100 represents the colour rendering of daylight

COMPACT FLUORESCENT LAMPS OR PL LAMPS

– These lamps use a tube which is curved or folded, they are an energy efficient light source, with longer life and reduced operating costs. The light is white in colour, similar to fluorescent fittings. CFL’s have integrated gear and PL lamps use external gear

CORRELATED COLOUR TEMPERATURE (CCT)

– The description used to describe the effect of heating on an object until it glows incandescently, the emitted radiation, and apparent colour, changed proportional to the temperature, easily envisioned when considering hot metal in a forge that glows red, then orange, and then white as the temperature increased. Measured in degrees Kelvin:
2700K – 3000KWarm White
3500K – 4000KNatural White
4000K – 5000KCool White
6500K plusDaylight

CUT OUT DIMESION

– Size of hole required to install luminaire

DAYLIGHT SENSOR

– A device which senses the amount of daylight in a room or outside and switches the luminaire on and off accordingly

DIMMING

– Many commercial and domestic luminaires are available as a dimmable version option. Generally this requires a different driver to the standard fixed output driver and also may require wiring on site to operate/control the dimming function

DOWNLIGHTING

– Light which is cast downward from a fixture. The most common and direct form of lighting

EDGE LIT

– All Lux Panels are edge lit, this means that the LED chips are positioned vertically around the perimeter of the panel. This provides an excellent uniformly illuminated panel in a fixture as slim as 8mm.

EDISON SCREW (ES)

– A lamps that features a screws thread for a positive fit in the lampholder, common sizes include E14, E27 and E40

ELECTRONIC CONTROL GEAR (ECG)

– A device that uses semi-conductor components to operate a discharge lamp

EMERGENCY LIGHTING

– Is to allow the safe evacuation of an area in the event of a mains failure. The positioning and number of emergency lighting luminaires is detailed in an OHS act standard. It is vital that emergency lighting is maintained correctly to ensure batteries are conditioned so it operated when required

FLUORESCENT LAMP

– A lamp consisting of a tube filled with argon, along with krypton or other inert gas

FLUX/LUMINOUS FLUX

– Luminous flux is the measure of the perceived power of light, adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light. It is expressed in lumens (lm)

FREQUENCY

– Is the rate that the power supply wavelength fluctuates and s measured in Hertz

GENERAL LIGHTING

– Lighting to illuminate the general area without supplementary task lighting

HEAT SINK

– A component or integral part of the LED luminaire/lamp that conducts or convects heat away from the LED chip

HID

– High Intensity Discharge lamps include High pressure sodium, Metal Halide and Mercury Vapour

HIGH BAY

– A lighting fixture used in industrial applications where the ceiling height exceeds 5.5m. Common in retail, industrial, warehouse and manufacturing spaces

HIGH PRESSURE SODIUM (HPS)

– A High Pressure Sodium lamp is a gas discharge lamp that uses an electric arc through vaporised sodium metal to produce light. The light is orange in colour similar to street lighting

IGNITOR

– A device which produces a high voltage pulse across a discharge lamps to aid starting

ILLUMINANCE

– The intensity of light falling on a surface area. If the area is measured in square feet, the unit of illuminance is foot-candles. If measured in square meters the illuminance is lux (lx)

INGRESS PROTECTION (IP) RATING

– A system that identifies the protection that a lamp or luminaire has against solid objects and water. The first digit being solid object protection and the second one resistance to water. So IP65 would be dust tight (6) and protection against low pressure jets from any angle (5). ingress protection

JUNCTION

– The p-n junction in a diode, for instance LED, where positively charged and negatively charge materials exchange electrons, emitting photons and generating heat which converts to light

JUNCTION TEMPERATURE

– The temperature in the vicinity of an LED’s p-n junction. Controlling the junction temperature is critical for achieving the optimal balance between lumen output and lumen maintenance

LAMP

– Also known as globe or bulb

LAMP LUMEN DEPRECIATION (LLD)

– Describes the percentage of light lost relative to the initial lumen output.

LIGHT OUTPUT RATION (LOR)

– Light Output Ration is the percentage difference between the luminous flux emitted by the light source and the amount emitted from the fixture is housed in.

LM/WATT

– Lumens per Watt, a measure of efficiency

LED

– Light Emitting Diode. An LED is a solid-state semiconductor device that converts electrical energy directly into light. On its most basic level, the semiconductor is comprised of two regions. The p-region contains positive electrical charges while the n-region contains negative electrical charges. When voltage is applied and current begins to flow, the electrons move across the n-region into the p-region. The process of an electron moving through the p-n junction releases energy. The dispersion of this energy produces photons with visible wavelengths. Most LED’s emit a blue light as that is the most efficient format, a phosphor coating turns the blue light into the white light required

LED DRIVER

– An electronic device which converts input power into a constant current source despite fluctuation in voltage. It is a critical component that has to be matched to the power requirements of the LED chip and also have quality components. Drivers which use inferior components will fail before the rated life of the LED chip, reducing the claimed life by as much as 50%

LOWBAY

– Also known as a canopy fitting is a lighting fixture used in industrial applications where the ceiling height lower than 5.5m. Common in retail and manufacturing spaces.

LUMEN (lm)

– The international (SI) unit of luminous flux. Lumens will become the measure of light output as watts cannot be a reliable measure due to the different efficacy of light sources and the ongoing improvement in LED efficacy through development

LUMEN MAINTENANCE

– The luminous flux at a given time in the life of a luminaire. This is expressed as a percentage of the initial luminous flux. This usually determines the rated life of a lamp as to the point it should be replaced

LUMINANCE

– The surface brightness of an object and measured in candelas/m²

LUMINAIRE

– A lighting fixture complete with installed lamps or light source.

LUMINOUS EFFICIENCY

– The percentage of total lamp lumens that a lighting fixture, luminaire, or system emits, minus any blocked or wasted light.

LUX (lx)

– The international (SI) unit of illuminance, or luminous flux incident on a unit are, frequently defined as one lumen per square meter (lm/m²)

MAINTAINED EMERGENCY

– A Maintained emergency luminaire is able to be used for both general and emergency lighting, a second live cable allows it to be turned on/off as required and detect a mains power circuit failure.

METAL HALIDE (MH)

– A Metal Halide lamp is an electric lamp that produces light by an electric arc through a gaseous mixture of vaporised mercury and metal halides (compounds of metals with bromine or iodine), the light is white in colour, similar to fluorescent lighting

MERCURY VAPOUR (MV)

– A Mercury Vapour is a gas discharge lamp that uses an electric arc through vaporised mercury to produce light. The light is white in colour, similar to fluorescent fittings

NARROW BEAM

– A smooth mirror like reflector that creates the most focused, powerful and intense beam of light, used mainly for lighting in a distance or spot lighting

NON-MAINTAINED EMERGENCY

– a Non-Maintained emergency luminaire ONLY operates in emergency mode and not for general lighting

OPTIC

– The components of a luminaire such as reflectors, refractors, protectors which make up the light emitting section

PHOTOMETRIC DATA

– Is a generic term for light output and distribution data for a lamp or luminaire and can be shown in many formats. Generally data is produced using the IES or ELUMDAT method to provide a .ies or .ldt computer file for use in a lighting design program such as Relux or Dialux.

POWER FACTOR (PF)

– The ration between the useful (true) power (kW) to the total (apparent) power (kVA) consumed by an AC electrical circuit. It measures how efficiently electrical power is converted into useful work output. The ideal is to have a power factor is unity, or one. Anything less than one means that extra power is required to achieve the actual task at hand.

POWER FACTOR CORRECTION

– In a ccg a capacitor is used and in ecg’s a system of inductors, capacitors, or voltage convertors are used to adjust the power factor toward the ideal power factor 1.0.

REFLECTOR

– A device used to reflect light onto a surface.

REFRACTOR

– A device used to redirect the light output from a lamp when the light passes through it.

SMDs

– Surface Mount LED’s

VOLTAGE

– The difference in electrical potential between two points of an electrical circuit

WATT (W)

– The unit for measuring electrical power.

WIDE BEAM

– A dimpled reflector similar to a golf ball to create a wider and more strikingly even light spread, used mainly for area lighting and signage