Technology-Understanding LED Lighting

Technology-Understanding LED Lighting

1. LED

LED is an acronym that stands for “Light Emitting Diode”.

2. SSL

SSL is an acronym that stands for “Solid State Lighting”, a term used to describe semi-conductors used to convert electricity in to light.

3. CRI

Color Rendering Index, a measure of how a light source renders colors of objects, compared to a “perfect” reference light source. CRI is given a number from 0 to 100, with 100 being equivalent to the reference source.

4. CCT

Correlated Color Temperature; a measure of the color appearance of a white light source. CCT is measured on the Kelvin absolute temperature scale. White lighting products are most commonly available from 2700K (warm white) to 5000K (cool white).

5. Lumen

A measure of the total amount of visible light emitted by a source. For example, a 40 watt bulb emits 450 lumens, 60w/800lm, 75w/1100lm, 100w/1600lm, 150w/2600lm.

6. Lumen Depreciation

An LED lamp is considered dead when it is only producing 70% of its original rated lumen output, as opposed to an incandescent bulb that will experience “sudden failure” and emit no light at all.

7. Efficacy

The light output of a light source divided by the total electrical power output to that source, expressed in lumens/watt.

8. Luminaire

A lighting fixture complete with installed lamps and other accessories.

9. Lamp

Any replaceable component that produces light, not to be confused with luminaire which is a light fixture inclusive of the lamp.

10. Color Spectrum

The range of colors that are visible to the human eye.

11. Luminous Flux

The measure of the perceived power of light as measured in lumens (lm).

12. Foot Candles

The illumanance cast on a surface by a one candela source one foot away. One foot candle is equal to one lumen per square foot.

13. Down Light

Down light or “recessed light” is a light fixture that is installed in a hollow opening in a ceiling concentrating the light in a downward direction.