Glossary of Terms

Ambient Light
– The surrounding light within an environment
– The “positive” terminal of a diode.
Ambient Temperature
– The surrounding temperature within an environment.
– Unit of luminous intensity. One candela equals one lumen per steradian.
– Luminous intensity expressed in candelas.
– The “negative” terminal of a diode.
– A very small square of semi-conducting material. Also known as a “die,” it is the “active” light-emitting component of an LED.
Color (Dominant Wavelength)
– LEDs are designed to give off a specific color emission. The dominant wavelength is a quantitative measure of an LED color as perceived by the human eye and is usually measured in nanometers (a billionth of a meter). In order to specify an LED, you must specify the color or dominant wavelength range required for your application. Some applications may have color constraints in order to meet specific government specifications or regulatory guidelines.
Color Bin
– LEDs are sorted according to their wavelength or CIE coordinates into different groupings or “bins.”
Color Rendering Index (CRI)
– It is a measure of the quality of light. It is a measurement of the amount of color shift that objects undergo when lighted by a light source as compared with the color of those same objects when seen under a reference light “~ source of comparable color temperature. LED light CRI values generally range from 60 (average) to 90 (best). High CRI equates to sharper, crisper, more natural colored pictures while at the same time reducing glare. The higher the number, the truer the appearance of the light on objects. Incandescent lighting is 100 on the CRI.
Color Temperature
– A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approximately 2800K) and have a red-yellowish tone; daylight has a high color temperature (approximately 6000K) and appears bluish (the most popular fluorescent light, Cool White, is rated at 4100K). Lamps with color temperatures below 5000K tend to be more yellow/red, lamps rated between 5000 and 6000K are viewed as white, while lamps above 6000K tend to have a blue cast.
Correlated Color Temperature (CCT)
– measures light color. “Cool” colors have higher Kelvin temperatures (3600-5500 K); “warm” colors have lower color temperatures (2700-3000 K).
Dominant Wavelength
– A quantitative measure of the color of an LED as perceived by the human eye. It is usually measured in nanometers (a billionth of a meter).
– The unit is defined as the amount of illumination the inside surface of an imaginary 1-foot radius sphere would be receiving if there were a uniform point source of one candela in the exact center of the sphere. Basically, it is the amount of light that a single candle would provide to a 1ft. radius sphere. Global Warming – A gradual warming of the Earth’s atmosphere reportedly caused by the burning of fossil fuels and industrial pollutants.
Greenhouse Gases
– Carbon dioxide and other gases that reportedly contribute to the warming of the Earth’s atmosphere.
Hertz (Hz)
– An international measure of frequency or vibration equal to 1 cycle per second. The alternative current frequency used in North America is 60 hertz. In Europe and some other parts of the world it is 50 hertz.
- Density of the luminous flux incident upon a surface. It is the quotient of the luminous flux by the area of the surface when the latter is uniformly illuminated.
Kilowatt (kW)
– 1,000 watts. The basic unit of electric demand, equal to 1,000 watts; average household demand is 10 to 20 kilowatts.
Kilowatt Hour (kWh)
– A unit of work or energy equal to using 1,000 watts for one hour. A 100-watt light bulb burning for 10 hours uses one kilowatt-hour. Your bill is computed according to the number of kWhs that you use.
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 as a result, 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 which will allow electricity to pass throuqh 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.
– A measurement of light output. The higher the number, the more light is emitted.
Lumens per watt (Im/W)
– measures efficiency. The higher the number the more efficient the product.
Lumen Maintenance
– How well a LED light bulb is able to retain its intensity when compared to new bulb Typically a high power 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.
– Density of luminous flux Ieaving a surface in a particular direction. It is the quotient of the intensity of the source in the direction of measurement by the projected area of the source in that direction.
Luminous Efficiency
– The ratio of light output to power input.
Luminous Intensity
– A measure of the visibility of a light source generally expressed in candelas. It is defined as luminous flux per unit solid angle (steradian) in a given direction.
– 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.
Peak Wavelength
– The maximum wavelength of an LED
– SSL means Solid State Lighting. It does not use heating of a thin fragile filament to create light. Rather it uses electrical current passing through a chemical which will get excited and thus emit light.
Voltage (Volt)
– The force which moves electric current through a conductor from the origin to the point of use.
– Meaning the LED product can be submerged into calm water but there is a limited depth as stated for each specific product. Most aluminum bodied LED products will not do well in salt or acidic water.
– ‘The unit for measurement od Metrical power; the energy required to light the product. The lower the wattage, the less energy is used. It defines the rate of energy consumption by an electrical device when it is in operation. The energy cost of operating an electncal device is calculated as its wattage times the hours of use. In single phase circuits, it is related to volts and amps by the formula:Volts x Amps x PowerFactor = Watts.
Watt per LED
– It can be confusing when two watt numbers are used in product specifications. For the application to smd hiqh powered LEDs, the 1 watt, 3 watt, 5 watt, etc, refers to the power consumption of that specific LED installed in that product The watt numbers expressed as light output are a comparison to an incandescent light bulb light output, for example- a 60 watt liqh toutput is equal to a 60 watt incandescent light bulb.
– White is deflned by Kelvin Temperature or Degrees Kelvin. Most will say that a Kelvin Temperature of 6000K plus is white with a bluish tint. And let’s say that 5000k -5500k is daylight/sunlight white. At 4200-4500K, it is called Cool white. At 2800.3300K it’s Warm white, which is the color temperature most incandescent light bulbs emit.

From 5500k on down the scale, the color becomes “warmer” due to the dominance of red and yellow hues In the opposite direction, whites will have cooler colors like blues and green becoming more apparent, thus they are called cool whites.