A

B

Base
The base of a lamp refers to the the part of the lamp that makes electrical connection with the fitting. These include: E14 (14mm Edison Skrew), E27, E40, B15 (15mm Bayonet), B22, R7s, G4, G9, GU10, GU5.3 and many more.

Beam Spread/angle
The angle over which the luminous intensity drops to a stated percentage (normally 10 or 50%) of its peak intensity.

Brightness
A visual sensation in which an area or object appears to emit more or less light than another.

Bulb
A light bulb is the colloquial term used to describe the common GLS, Incandescent lamp, or tungsten filament lamp that the large majority of consumers in the 20th century are used to. It's shape is similar to that of a bulbous plant root.

C

Ceiling light
A Ceiling light as the name suggests is a light that is mounted on the ceiling surface but is distinguished from Spotlights, Chandeliers and Pendants by the fact that there is no form of suspension as it is usually mounted flush with the ceiling. Usually these fittings are non directional as opposed to multi-directional spotlights.

Chandelier
A chandelier is a branched decorative ceiling-mounted light fixture with two or more arms bearing lights. Chandeliers are often ornate, sometimes containing dozens of lamps and complex arrays of glass or crystal prisms to illuminate a room with refracted light.

Class
Electrical Class refers to the type of insulation a light fitting requires. Class 0 appliances have no protective-earth connection and feature only a single level of insulation and were intended for use in dry areas. In most countries, the sale of Class 0 mains-voltage appliances is prohibited today, as a single fault could cause an electric shock or fire. The International Electro technical Commission is in the process of removing provisions for Class 0 devices from its standards. It can be expected that the Class 0 concept will eventually disappear from the international market, in favour of Class II devices. Class 1 insulation requires that the metal body and other exposed metal parts of the device is connected to earth via a ""grounding"" wire (usually yellow/green) which is earthed at the main service panel; but only basic insulation of the conductors is needed. This equipment is easily identified by a third pin on the power plug for the grounding connection.


Class 2 insulation means that the device is double insulated. This is used on some appliances such as electric shavers, hair dryers and portable power tools. Double insulation requires that the devices have both basic and supplementary insulation, each of which is sufficient to prevent electric shock. All internal electrically energized components are totally enclosed within an insulated body that prevents any contact with ""live"" parts and hence does not require a safety connection to electrical earth. In the EU, double insulated appliances all are marked with a symbol of two squares, one inside the other. A Class III appliance is designed to be supplied from a SELV (Separated or Safety Extra-Low Voltage) power source. The voltage from a SELV supply is low enough that under normal conditions a person can safely come into contact with it without risk of electrical shock. The extra safety features built into Class I and Class II appliances are therefore not required. For medical devices compliance with Class III is not considered sufficient protection.

Colour Rendering Index
The Colour Rendering Index is a reference to the degree to which a light displays the true colour of illuminated objects. A lamp with a high Colour rendering index accurately shows an items true colour while a low Colour Rendering Index creates an appearance that all the colours appear similar.

Colour Temperature
A measure of colour appearance of a light source and expressed in degrees Kelvin.

Compact Fluorescent (CFL)
A compact fluorescent lamp (CFL) or energy saving lamp is a type of fluorescent lamp. Many CFLs are designed to replace an incandescent lamp and can fit into most existing light fixtures formerly used for incandescents. Compared to general service incandescent lamps giving the same amount of visible light, CFLs use 80% less power and have a longer (6X) rated life. Like all fluorescent lamps, CFLs contain mercury, which complicates their disposal. CFL's radiate a different light spectrum compared with that of incandescent lamps. These colours include cool and warm white.

Components
Components are the electrical hardware used to make up a light fitting.

D

DB Board:
A distribution board (or panel board, breaker panel, or circuit breaker) is a component of an electricity supply system which divides an electrical power feed into subsidiary circuits, while providing a protective fuse or circuit breaker for each circuit, in a common enclosure. Normally, a main switch, and in recent boards, one or more Residual-current devices or Residual Current Breakers with Over current protection, will also be incorporated.
Diffused Lighting
Lighting in which the light on the working plane or on an object is not predominantly from another direction.

Diffuser:
A reflecting of transmitting medium in which the light is so scattered as to give approximately uniform luminance in all directions.

Dimmer:
A device in the electrical supply circuit for varying the luminous flux of lamps

Dimming:
Dimmable lighting systems were developed originally to meet the need for lighting that was easier on the eye. To an increasing extent, these systems are now also being used for cost saving reasons. Users can control the lighting with remote controls and switches, or control circuits with daylight sensors can be used. Leading edge phase dimming is used for low voltage tungsten halogen lamps operated with magnetic transformers. Trailing edge phase dimming is generally used for those lamps operated with electronic transformers. Compact fluorescent lamps (dimming range 3% to 100%) and fluorescent tubes (dimming range 1% to 100%) with electronic control gear are dimmed via a 1-10 V interface. Cables can either be laid separately (recommended for cable lengths > 100 m) or together, provided the requirements of wiring regulations are met.

Directional Lighting:
Lighting in which the light on a working plane or object is predominantly from a particular direction.

Discharge Lamp:
Gas-discharge lamps generate light by sending an electrical discharge through an ionized gas, i.e. a plasma. The character of the gas discharge critically depends on the frequency or modulation of the current. Typically, such lamps use a noble gas (argon, neon, krypton and xenon) or a mixture of these gases. Most lamps are filled with additional materials, like mercury, sodium, and/or metal halides. In operation the gas is ionized, and free electrons, accelerated by the electrical field in the tube, collide with gas and metal atoms. Some electrons circling around the gas and metal atoms are excited by these collisions, bringing them to a higher energy state. When the electron falls back to its original state, it emits a photon, resulting in visible light or ultraviolet radiation. Ultraviolet radiation is converted to visible light by a fluorescent coating on the inside of the lamp's glass surface for some lamp types. The fluorescent lamp is perhaps the best known gas-discharge lamp. Gas-discharge lamps offer long life and high light efficiency, but are more complicated to manufacture, and they require electronics to provide the correct current flow through the gas.

Down lighting:
Down-lighting is most common lighting method, with fixtures on or recessed in the ceiling casting light downward. This tends to be the most used method, used in both offices and homes. Although it is easy to design it has dramatic problems with glare and excess energy consumption due to large number of fittings.

Downlight:
A downlight is a light fixture that is installed into a hollow opening in a ceiling. When installed it appears to have light shining from a hole in the ceiling, concentrating the light in a downward direction as a broad floodlight or narrow spotlight. There are two parts to recessed lights, the trim and housing. The trim is the visible portion of the light. It is the insert that is seen when looking up into the fixture, and also includes the thin lining around the edge of the light. The housing is the fixture itself that is installed inside the ceiling and contains the lamp holder.

E

Lighting provided for use when the supply to the normal lighting fails. Escape Lighting is lighting that ensures an escape route will he highlighted when regular lighting fails. Standby Lighting is emergency lighting that enables certain activities to continue after regular power supply is interrupted.

Energy efficiency is using less energy to provide the same level of energy service. For example, installing fluorescent lights and/or skylights instead of incandescent lights to attain the same level of illumination. Compact fluorescent lights use four fifths less energy and may last 6 to 10 times longer than incandescent light bulbs. Efficient energy use is achieved primarily by means of a more efficient technology or processes rather than by changes in individual behaviour.

F

Impression of fluctuating luminance or colour.

A Fluorescent Lamp is a gas discharge lamp using low pressure mercury vapour lamp in which almost all of the light is produced by the excitation of fluorescent phosphors on the inner surface of the lamp by ultra violet radiation. There are tubular, circular and 2D fluorescent lamps and also compact fluorescent lamps. The tube diameter is often expressed in eighths of an inch (e.g. T5 = 5/8'' = 16 mm).

Front lighting is also quite a common lighting method, but tends to make the subject look flat as its casts almost no visible shadows. Lighting from the side is the less common, as it tends to produce glare near eye level. Backlighting either around or through an object is mainly for accent.

G

Glare is difficulty seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night or Stadium Lighting. Glare can be generally divided into two types, discomfort glare and disability glare. Discomfort glare results in an instinctive desire to look away from a bright light source or difficulty in seeing a task. Disability glare renders the task impossible to view, such as when driving westward at sunset. Disability glare is often caused by the inter-reflection of light within the eyeball, reducing the contrast between task and glare source to the point where the task cannot be distinguished.

H

A Sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure. Because sodium vapor lamps cause less light pollution than mercury-vapor lamps, many cities that have large astronomical observatories employ them. these lamps have poor colour rendering.

I

A heat lamp is an incandescent light bulb that is used for the principal purpose of creating heat. The spectrum of black body radiation emitted by the lamp is shifted to produce more infrared light. Many heat lamps include a red filter to minimize the amount of visible light emitted. Heat lamps are commonly used in shower and bathrooms to warm bathers and in food-preparation areas of restaurants to keep food warm before serving. They are also commonly used for animal husbandry. Lights used for poultry are often called brooding lamps. Aside from young birds, other types of animals which can benefit from heat lamps include reptiles, amphibians, insects, arachnids, and the young of some mammals.

Ingress Protection Rating. Protection against foreign objects and liquids.

J

K

A temperature scale used to designate the colour temperature of a light source

L

A light-emitting diode (LED)is a semiconductor light source. LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. Modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness. The LED is based on the semiconductor diode. When a diode is switched on, electrons are able to recombine with holes within the lamp, releasing energy in the form of photons. This effect is called electroluminescence and the colour of the light is determined by the energy gap of the semiconductor. An LED is usually small in area (less than 1 mm2), and integrated optical components (lens) are used to shape its radiation pattern and assist in reflection. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output.

Luminaire efficiency is an important criterion in gauging the energy efficiency of a luminaire. It is the ratio between the luminous flux emitted by the luminaire to the luminous flux of the lamp (or lamps) installed in the luminaire.

A measure of the illuminating power of a light source in a particular direction, independent of distance from the source. Unit = candela (cd)

Luminous intensity should not be confused with another photometric unit, luminous flux, which is the total perceived power emitted in all directions. Luminous intensity is the perceived power per unit solid angle.

M

Mounting height refers to the suggested height that a light fitting should be mounted for optimum use.

N

A neon lamp is a gas discharge lamp containing primarily neon gas at low pressure. The term is sometimes used for similar devices filled with other noble gases, usually to produce different colors.

O

An outdoor light is any light that is suitable for outdoor use and is protected by from the elements. This protection is observed by reference to it's IP rating which determines a fittings protection against liquid and foreign objects.

P

This vision typically occurs when the eye can see at around 30 lux where colour and detail are clear.

Project lighting refers to lighting that is used in specific industries as task lighting. The combination of specifically designed Luminaires and specific lamps allows for the most efficant lighting for various tasks in industry and commerce.

Q

QI Premium refers to the quartz used in the make up of linear halogen lamps.

R

Reflectors make use of reflective surfaces to direct light where it is needed. They function on the basis of the law of reflection. They may be convergent or divergent. Most divergent reflectors have a white coating. The efficiency and the way in which light is distributed are primarily determined by the mounting depth of the lamp and dimensions of the reflector. Their shape has only a small influence. In the case of convergent reflectors, which nowadays are almost exclusively manufactured from polished anodised aluminium, the contours of the reflector play an important role. The following forms are the most common: Spherical reflectors return the light to the focal point; they are often used as additional reflectors for point-source lamps and spotlights; Elliptical reflectors send the rays of light to a second focal point. These reflectors enable a large quantity of light to be directed through small openings, provided small lamps with high luminances are used. The disadvantages are high temperatures at the focal point due to the concentration of the light and heat; Parabolic reflectors send the light from a light source out in a parallel beam. The maximum luminous intensity is determined by the luminance of the light source and the diameter of the reflector. Parabolic reflectors are used predominantly in spotlights and narrow angle luminaires.

Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at an angle. Refraction of light is the most commonly observed phenomenon, but any type of wave can refract when it interacts with a medium.

S

A Spotlight as the name suggests illuminates a specific 'spot'. This fittings usually mounted on the ceiling or wall are directional and usually have some form of reflector lamp to concentrate the beam of light.

T

Current is passed through a wire to heat it to high temperature. The model here is the sun with its surface temperature of 6000K. Because it has the highest melting point of any metal (3683K), the element tungsten is best suited for this purpose. Examples: incandescent lamps and tungsten-halogen lamps.

U

Uplighting is a less common lighting method, often used to bounce indirect light off the ceiling and back down. It is commonly used in lighting applications that require minimal glare and uniform general illuminance levels. Uplighting (indirect) uses a diffuse surface to reflect light in a space and can minimize disabling glare on computer displays and other dark glossy surfaces. It gives a more uniform presentation of the light output in operation. However indirect lighting is completely reliant upon the reflectance value of the surface. While indirect lighting can create a diffused and shadow free light effect it can be regarded as an uneconomical lighting principle.

V

The volt is defined as the value of the voltage across a conductor when a current of one ampere dissipates one watt of power in the conductor. It is named in honour of the Italian physicist Alessandro Volta (1745-1827), who invented the voltaic pile, possibly the first chemical battery.

W

Watt
The watt named after Scottish engineer James Watt is the unit that measures the rate of energy conversion. It is defined as one joule per second.

X

Y

Z