L.E.D.:
LED means light emitting diode. LEDs are a solid state device and do not require heating of a filament to create light. Rather, electricity is passed through a chemical compound that is excited and that generates light. LEDs are not bulbs or lamps in the true sense of the word and application. LEDs require a lot of work to make them ready to be used by the consumer. They need to be placed on a circuit board or other material that will allow electricity to pass through it at a specific voltage and current, and with components required to operate them at specific voltages such as 12vdc, 24vdc or 120vac. They do not come ready to plug into a 12volt or 120 volt power source. These are LEDs.
LED Bar:
Refers to a solid strip of material on which LEDs have been soldered to, along with resistors and other components that a specific product requires to make them operate at the stated operating voltage. The Bars are usually an enclosed strip of LEDs. Enclosures are plastics, or aluminum, or metal composites with various types of lens/cover plates
LED Cluster or Array:
A group of LEDs set in a square, rectangular or linear pattern, and formatted to be operated at a specific voltage. They will always include two wires called leads. One is positive, the other negative.
LED Drivers:
are current control devices that replace the need for resistors. LED Drivers respond to the changing input voltage while maintaining a constant amount of current (output power) to the LED as its electrical properties change with temperature.
LED Lighting:
A general term used by those who do not know the specific type or category of LED lighting they are after. LED lighting includes LED bulbs and fixtures, flashlights, strips, clusters and other LED light sources.
LED Strip:
LED Strips are usually printed circuit boards with LEDs soldered to the board. The strip can be rigid, or flexible and without any enclosure to protect the LED and circuit.
Low Voltage:
With LEDs, that means 12vDC 24vDC or 48vDC, as opposed to 110/120vac which is high voltage. With LEDs, low voltage is commonly 12vdc sometimes at 24vdc. To run these low voltage lights, power will have to be sent to the light through a power supply/transformer/adapter that is hooked up to 110/120/240vac power lines. The actual voltage reaching the light will be at 12vdc.
Lumen Maintenance:
How well a LED light bulb is able to retain its intensity when compared to new. Typically a high power smd LED bulb will retain 70% of its intensity for 40,000-50,000 hours. That means a good quality LED bulb will run 8 hours a day for 13 years at 70% of its new condition. No other light source can do this.
Lumens:
The unit of luminous flux in the International System, equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions. Used to measure light bulbs as stand alone light sources. Lighting fixtures are measured by lux output which is lumens per square meter. See for a better(?) understanding - Lumens, Illuminance,
Lux:
Typically used to measure the light intensity produced by a lighting fixture. The higher the lux reading the more light the lighting fixture is producing over a given area. Known as lumens per square meter
mA
stands for milliamp. 1000mA equals 1.0 amp. All LEDs run on current and current is measured in milliamps. All LED products have a mA rating at which they are to be powered at.
Max Rated Temperature:, or Operating Temperature
is the ambient temperature where the LED light source is installed at and should be maintained at. In most case that is around 40-50° Celsius. That is comparable to 104° F to 122° F. Operating a LED light source beyond the Operating temperature will lower the LED's life span or kill it.
MCD: or Millicandela
is used to rank/denote the brightness of an LED. 1000mcd is equal to one Candela. The higher the mcd number, the brighter the light the LED emits.
Nanometers: or nm.
Used to measure the wavelengths of light. The lower the wavelength e.g.. 400nm the bluer and stronger the light source. Longer wavelengths above 600nm are red. Above 680nm, they fall into the Infra Red category, which is colorless to our eyes. White LEDs have no specific wavelength. They are measured by the color of white against the chromaticity scale.
Operating Life:
usually refers to the number of hours a specific type of LED is expected to be operational. With high powered LEDs, that usually means life after it loses 10-15% or more rated output after 1000 or more hours of run time. The Cree and Luxeon LEDs are rated for 50,000 at 75% maintenance for 50,000 hours.
