Glossary of Terms

Accent Lighting Technique that emphasizes a particular object or draws attention to a particular area. Accent Lighting usually utilizes a tight beam angle PAR, MR or GU light source.
Alternating Current (AC) Electrical current in which the flow of electric charge continually reverses direction.
Ambient Lighting Lighting designed to provide uniform light levels throughout and area.
Backlighting Use of light source to illuminate from behind without protrusion through the panel.
Ballast The device that limits amount of current in an electrical circuit.
Beam Angle Size of the cone of light produced by lighting source measured in degrees.
Can Light Short for Canister Light. Another name for a recessed light or down light which is a fixture installed into a hollow opening in a ceiling.
CE Certifies product has met EU (European) consumer safety, health and or environmental requirements.
CFL Compact Fluorescent which consume less energy than Incandescent with the negative aspect of Mercury/Poison content.
Color Temperature (CT) This is a measurement of the Yellowness or Blueness of a White light source based on a Kelvin number. Yellowish White described as Warm White is compared to Incandescent Lamps which have a lower Kelvin temperature number around 2700-3000 range. White and Bluish White described as Natural White and Cold White have a higher Kelvin Temperature of 5000-7000.
Cool White Kelvin color temperature of 5500-7000
CRI Color Rendering international system to rate lighting device ability to render object colors. The higher the CRI (based on a 0-100 scale), the greater the color fidelity of the lighting source. Natural outdoor light has a CRI of 100.
Diffuser Optical element used to mix light ray to improve uniformity of light.
Direct Current (DC) Electrical current which the flow of electric charge moves in one direction only.
Down Light Light source set in a metal cylinder. Mounted or recessed into the ceiling so the beam of light is directed downward.
Driver LED power supply providing either a constant level of current or a constant level of voltage.
E26/E27 Edison Screw fitting system designated at standard screw-in bulb bases. Also referred to as a “Medium” or “Standard” Base. E26 Base is U.S. standard. E27 is European standard. The number after the E refers to the number of millimeters of the base.
Flood Light A lamp that provides a broad beam intended to light a general area.
Fluorescent Tube Light source consisting of a glass tube filled with low pressure mercury vapor. Electrical discharge through the vapor produces ultraviolet light that excites phosphor materials on the inside of the tube which emit visible light.
Flux Sum of Lumens emitted by a light source.
Foot-candle (FC) Unit of light falling onto a surface. One foot-candle is the light level on a surface one foot from a standard candle.
GU A bipin base code. Each Pin has two diameters. Being larger near the ends in order to twist and lock into position in the socket. GU10 Being one of the most common base products almost always 110/120V AC.
Heat Dissipation This is the transition of thermal energy form a hotter object to a cooler object. With LED heat sinks made from high quality aluminum and other alloys accomplish this.
High Intensity Discharge (HID) Electrical lamp filled with gases and other compounds in which an electric arc is passed between tungsten electrodes to produce light.
High Pressure Sodium (HPS) High Intensity discharge lamp offering a warm Correlated Color Temperature (CCT) high levels of efficiency, ling life with very modest levels of CRI.
Incandescent Lighting Light produced when a filament is heated to incandescence using electric current. Incandescent lighting is very inefficient since most of the energy is wasted as heat rather than light
Kelvin (K) Unit of temperature starting from absolute zero.
Kelvin Temperature Color measure as to Yellowness or Blueness of the color white. The higher the Kelvin temperature the more Blue than White.
Kilowatt (KW) Measure of electrical power equal to 1000 Watts.
LED Light Emitting Diode solid state semiconductor device that converts electrical energy directly into light.
LM-79 IESNA approved method for the electrical and photometric test of solid state lighting devices. Specifies procedures for measuring total luminous flux electrical power, luminous efficacy.
LM-80 IESNA approved method of measuring Lumen depreciation of LED Light sources. It is related to the effective useful life of the product.
Lumen Measurement of luminous flux of quantity of light emitted by a source. Higher the Lumen, the Brighter the Light.
Lumen Maintenance Describes how long a light source will retain a certain percentage of its initial Lumen output.
Luminaries Lighting fixture complete with lamp, housing, power supply and optical components used to direct light.
Luminous Efficacy Measurement of how effective the light source is in converting electrical energy to Lumens of visible light. Usually expressed in Lumens per watt (LPW)
Lux Unit of luminance or density of light falling onto a surface. One lux is equal to one lumen per square meter.
Metal Halide (MH) High Intensity light source produced by the radiation from mercury, plus halides of metals such as sodium, scandium, indium, and symposium.
MR A bipin base code for a 2 sharp pin push in base. Almost always 12V Product. The MR16 LED lamps are a very popular replacement for Halogen.
Natural White Light with a Kelvin Temperature between 4500 and 5500.
PAR Lamp Acronym for a Parabolic Reflector. PAR20, PAR30, PAR38 are Most Common.
Power Supply Device that supplies electrical or energy. Most LED Power Supplies Convert Line Voltage (110AC) to 12 & 24V DC.
RGB Acronym for Red, Green, and Blue. These are the 3 primary colors of light. Combinations of these 3 colors to create wide variety of other colors.
RoHs Compliance Restricts the use of certain dangerous substances commonly used in electrical and electronic equipment.
SMD (Surface Mount) LED’s are soldered to the surface of the circuit board. The LED Die is integrated into the package design. Surface Mounted LEDs can be assembled faster and with better quality than Dip through-Hole Components.
Spotlight A lamp that produces a narrow beam angle designed to illuminate a specific targeted area.
Tube Light Term used to describe a fluorescent tube. Most typical sizes are T5, T8, T10 and T12. T indicates the shape of the bulb is tubular. Typical diameters T5 =5/8 ” T8 =1″ T12=1 1/2″ Traditionally the T8, T10, and T12 use the dual pin G13 Socket.
Ultraviolet (UV) Invisible radiation that is shorter in wavelength and higher in frequency than visible violet light. UV rays are light waves that are similar to the light from the sun. UV radiation can cause oxidation, fading of colors of furniture, carpet, draperies and art work.
Warm White White color with a Kelvin temperature between 2800-3200.
Wavelength Distance between two points of corresponding phase and is equal to waveform velocity divided by frequency.