LEDs consist of small semiconductors, which glow during exposure to electric current. This current flows between LED anodes, which are positively charged electrodes, and LED cathodes, which are negatively charged electrodes.
As the electrons stream across the semiconductor, they create electromagnetic radiation. Some forms of this electromagnetic radiation can take the form of visible light.
The light that is created an LED can be of any colour and can even be ultraviolet or infrared. This colour depends on the material used to make the semiconductor and the current run through it. Tiny LEDs are already replacing the tubes that light up LCD HDTVs to make dramatically thinner televisions.
How an LED TV works
Life: The life of an LED light bulb can be as long as 50,000 hours. This time frame is based on ideal conditions with the LED light bulb not being exposed to extreme heat or cold, or moisture.
Air circulation: Poor air circulation can reduce in the life of an LED light. The bulb itself produces a small amount of heat, but it is enough to result in lessthan optimal conditions for LED bulbs.
Applications: LED lights have found a permanent home in Exit signs, traffic lights, store displays, and anywhere where coloured light is needed. LEDs are energy efficient.
The Future of LED
THE STORY SO FAR
1962:The first practical visible-spectrum (red) LED was developed by Nick Holonyak. Holonyak is seen as the "father of the light-emitting diodeā??.
1972:M. George Craford is a former graduate student of Holonyak, invented the first yellow LED
1968: Hewlett Packard (HP) introduced LEDs.
1970:Commercially successful LED devices at less than five cents each were produced by Fairchild Optoelectronics.
1977:All LED TV screen is credited to J.P. Mitchell.
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