Ballast:
An electrical device used with fluorescent or HID (high intensity discharge) lamps to supply sufficient voltage to start and operate the lamp but then to limit the current during operation.
Base:
The portion of the lamp (light bulb) that provides a means of physically connecting the lamp to a socket or lamp holder.
Beam Spread:
A measure of the spread of light from a reflectorized light source, a special-shaped lamp with a reflective coating inside the bulb to direct the light forward. The beam spread may be very narrow (narrow spot), very wide (wide flood), or something in-between (narrow flood, for example).
CCFL:
A cold cathode fluorescent lamp is a type of fluorescent lamp in which the cathode (an electron-emitting electrode inside the lamp) is not independently heated although the cathode can become quite hot once the CCFL has been operating. Screw-in CCFLs come in several different wattages (present range is 3W to 18W) and several different shapes (spiral, globe, reflector, A-line, torpedo) and are generally characterized by a very thin glass envelope (2mm-4mm in diameter), a longer rated life than compact fluorescent lamps (often 25,000 hours), and a very good range of dimmability (down to 30%).
Cathode:
An electrode that emits electrons. A fluorescent lamp cathode emits or discharges electrons to the cathode at the other end of the lamp (light bulb).
Colour Temperature:
A measure of the colour appearance of a light source which helps describe the apparent "warmth" (reddish) or "coolness" (bluish) of that light source. Generally, light sources below 3200K are considered "warm;" while those above 4000K are considered "cool" light sources. The colour temperature of a lamp has nothing to do with how hot the lamp will get or how much heat is given off by the lamp. The letter, K, stands for Kelvin.
This table may help you better understand the concept of Colour Temperature.
Colour Temperature |
Light Source |
| 1600K | Sunrise or Sunset |
| 1800K | Candlelight |
| 1800K | Gaslight |
| 2800K | Household Incandescent Lamp |
| 3000K | Warm White Fluorescent Lamp |
| 3500K | Neutral White Fluorescent Lamp |
| 4100K | Cool White Fluorescent Lamp |
| 5000K | Professional Light Booth |
| 5200K | Bright Midday Sun |
| 6500K | Heavily Overcast Sky |
Compact Fluorescent Lamp (CFL):
A generic name used for a whole family of small, single-ended fluorescent lamps with a folded, bridged, or spiral glass tube design and with high colour rendering (CRI > 80) and a long life (> 8,000 hours).
Dimmer:
A device in an electrical circuit used for varying the brightness of lamps in a lighting installation. Dimming controls are ideal for almost any type of room because they can change the amount of lighting to suit each mood or activity and they can help you look good. The use of dimmers with incandescent, xenon, and halogen light sources also increases the life of the lamps and decreases the use of electrical energy.
Direct Current:
Electric current without alterations. DC current is usually supplied by a battery, a transformer, or photovoltaic cells.
Efficacy:
A measure used to compare light output to energy consumption. Efficacy is measured in lumens per watt. A 100-watt light source producing 1750 lumens of light has an efficacy (efficiency) of 17.5 lumens per watt (L/W).
Filament:
A tungsten wire that incandesces or lights up when an electric current runs through it.
Fluorescent Lamp:
A low-pressure mercury electric-discharge lamp (light bulb) in which a phosphor coating on the inside of the glass tubing transforms some of the ultraviolet energy created inside the lamp into visible light.
Halogen Lamp:
A type of incandescent lamp (light bulb) that contains halogen gases (such as iodine, chlorine, bromine, and fluorine), which slow the evaporation of the tungsten filament. Also, sometimes called a tungsten halogen lamp or a quartz lamp. The glass envelope that surrounds the filament of a halogen lamp should not be touched with bare hands. The natural oil from human hands will only help to shorten the life of halogen lamps. If you should accidentally touch the glass bulb, you should thoroughly remove your fingerprints with methylated spirit (denatured alcohol). To learn more about this topic click Halogen Lamps.
HID Lamp:
High intensity discharge (HID) lamps (light bulbs) have a longer life and provide more light (lumens) per watt than most other light sources. Available in mercury vapor, metal halide, high pressure sodium, and low pressure sodium types.
Incandescence:
Light emission by a heated filament.
Incandescent Lamp:
Lamp (light bulb) in which light is produced by means of an element heated to the point of incandescence by the passage of an electric current.
Infrared Radiation:
A type of invisible radiation for which the wavelengths are longer and frequency lower than those for visible radiation.
Lamp:
A light source such as an incandescent, halogen, or fluorescent lamp. A lamp is sometimes called a “light bulb” or simply a “bulb”.
LED:
Light emitting diode. A small electronic device that lights up when electricity is passed through it. LEDs are quite energy-efficient and have very long lives. They can be red, green, blue or white in colour.
Lumen:
A unit of measure used to describe the amount of light that a light source produces or emits. For reference please consult the table below.
Transformer:
An electrical device that transforms the line voltage of a facility (usually 120 volts for residential settings or 277 volts for commercial settings) into the voltage that a low voltage lighting system requires (12 volts or 24 volts).
Voltage:
The difference in electrical charge between two points in a circuit expressed in volts; the electric pressure that exists between two points and is capable of producing a flow of current when a closed circuit is connected between the two points; the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; synonyms: electrical potential, electromotive force, EMF; Formulae: volts = amps x ohms, V = I x R, voltage = electrical current x electrical resistance.
Wattage:
The amount of electrical power consumed by a lamp or light fixture measured in “watts”. One watt is equal to the power dissipated by 1 ampere of electrical current flowing across a resistance of 1 ohm or the power produced by 1 ampere of electrical current under an electromotive force of 1 volt. One horsepower is equal to 746 watts.
Formulae:
Watts = volts x amps, P = V x I, electrical power = electromotive force x electric current.
Xenon Lamp:
A type of incandescent lamp that contains xenon gas in the glass envelope. The primary reason that this is done is to lengthen the average rated life of the lamp. Depending on the lamp a typical xenon lamp may have a rated life of 10,000 hours whereas a similar halogen lamp may have a rated life of 2,000 hours. Unlike halogen lamps, xenon lamps may be touched with bare hands without affecting the rated life of the lamp. Xenon lamps also operate at cooler temperatures than halogen lamps. Like halogen lamps, xenon lamps may be dimmed (using the right dimmer) whether the lamp is rated for low voltage (12 volts or 24 volts) or line voltage (120 volts).