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What is the Circadian Rhythm?
It's the term used for the variations on biological activity during a 24 hour period.
One of the most important factors on humans circadian rhythm variations is light color and intensity. Soft yellowish light tends to calm, or slow down our concentration and mental agility, while strong blueish light tends to increase our brain activity.
What is CT?
Color Temperature (CT) is the term used to express the color tendency of the white light. It's measured in “Degrees Kelvin” (°K) and the usual range is from 2700°K for yellowish white up to 6500°K for blueish white.
The 4000°K value is referenced as LED neutral white light.
Why use LED Light?
Efficiency!!!
A 1W white LED typically generates a light amount of 100 Lumen, as much as a 2,5W fluorescent, or a 15W incandescent fridge lamp.
Longevity!!!
Life expectancy of 50.000 hours is common among LEDs in contrast with 10.000h for fluorescent and 1.000h for incandescent.
Ruggedness!!!
A LED is much more resistant to impact and vibration than standard light bulbs.
Environmental Impact!!!
LED’s don’t use toxic or hazardous materials. With few exceptions, fluorescent, and other low or high pressure lamps, do use toxic and/or hazardous materials.
What is a LM-80 report?
It is a longevity chart or data that tells you how many hours a LED endures until it reaches 80% of the amount of light it produced initially.
This 20% reduction of light after several continuous working hours is extremely dependent of temperature! In some cases a 10% increase of temperature may decrease LED life expectancy by 50%!
A good quality 1W white LED, reaches the 80% value after 50.000 hours at a normal 80° Centigrade package temperature.
What is a COB?
A Chip On Board (COB) is a piece of metal or ceramic, where the LED manufacturer places several LED chips, and connects them in a series/parallel array leaving only the global positive and negative terminals available. This method is used to increase light output, while reducing the implementation space and simplifying electrical connections
Why is Efficiency diferent from Efficacy?
Efficiency is the quantity of light emitted versus the power consumed, while Efficacy is the ratio between the light produced and the useful light.
This is an extremely important specification in LED devices, as well as on all types of luminaire design, since internal reflections may cause substantial reduction on the useful light. These losses contribute to unwanted heat generation.
What is CRI?
Color Rendering Index (CRI) is the numeric quantification of the quality of light, as defined by the International Commission on Illumination (CIE).
As the mane suggests, the higher the number, the better is object color perception.
It's range is from 0 to 100.
Some every day examples:
| Light Source | CRI |
| Economy Fluorescent or LED | 60 to 75 |
| High Quality Fluorescent or LED | 80 to 85 |
| Top Quality Fluorescent or LED | 90 to 98 |
| Incandescent Light Bulb | 100 |
| 50W Halogen | 100 |
| Street Light (Mercury Vapor) | 50 |
What is a LED?
A Light Emitting Diode (LED) is a solid state semiconductor device that emits light when excited with a direct current.
It is usually supplied in a suitable package for soldering into a printed circuit board.