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What is LED
LED (Light Emitting Diode) is an electric component with unique properties; it converts electric current directly into visible light. The light spectrum is determined by the material used to create it.
LED was developed during the 20th century; In the beginning only green LED light was available but with time more colors were made possible (blue LED light was introduced in 1971 for example) and light output has increased dramatically ever since.
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(Move over the picture)
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White light
As of today there are two methods in which to create white light:
- Mixing different wavelengths emitted by 3 different primary color LEDs - also known as RGB
- Using a phosphor material, a special coating which converts blue or UV light into white light (fluorescent light bulbs work on the same principle)
LED manufacturers make white light in temperatures ranging from about 2700K - 10,000K (K=Kelvin). The familiar light of an incandescent bulb is about 2700K and is referred to as "warm white". Warm light for that matter is referred to any light in temperatures of up to 3500K
Another important parameter is CRI (Color Rendering Index) which is measured in a scale of 1-100 and represents the ability of a light source to reproduce the colors of various objects faithfully in comparison with natural light source. The closer to 100 the CRI is the higher quality light we consider it to be.
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Measurements:
Ampere
Technical data provided by LED manufacturers about High Brightness LEDs (Luxeon brand for example) is given in Amp. Typical HB LEDs are designed to work on 350/700mA and some would work in well over 1500mA.
Volt
Unit of electric potential difference, which in our field is commonly 3-4.5V. Since working with different scales and measurements are confusing, we can convert them by using the Ohm Law, which describes the fundamental relationship between voltage, resistance, and current.
For ex. - 3.5V for a 350mA LED will give us a light output of 1.2W - we usually call these LEDS - 1W LED.
Commonly used LEDs for general illumination are 1W / 3W and 5W LEDs which are referred to as "Ultra Bright".
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What are the advantages of LEDs?
LEDs have a variety of advantages over other light sources:
- High-levels of brightness and intensity
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- High reliability (resistant to shock and vibration)
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- Low-voltage and current requirements
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The Future of LEDs
As LED technology continues to evolve, different applications and uses are constantly being created. LEDs were named "the 4th generation" in lighting, and today they are not looked at as just indicator light, but as a valid option to replace just about any other light source used today.
According to the U.S. Department Energy, no other lighting technology offers as much potential to save energy and enhance the quality of our building environments, and estimates state that 70% of the global domestic market will be LED based as well by the end of the first quarter of this century.
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