LED’s, what is it?

1. LED’s, what is it? • LED: (Light-emitting diode) is an electric device that allows current to go in one way. • LED uses a special material called semiconductors(example: silicon). Semiconductors only allow the current to flow in one direction.

2. How do LED’s work? • a LED is a “semiconductor” which makes light using solid state electronics • semiconductor=material with an varying ability to conduct electrical current • a diode ( in the light-emitting diode) is a layer made of electron rich material divided by a layer of electron deficient material • this forms a junction • power applied to the junction energizes the electrons in the electron rich layer amounting to the production of light as well as photo emission • the chemical composition of the layers decides the colour the light will be • LED’s are more energy efficient than incandescent counterparts because: -incandescent bulbs only create white light which then have to be filtered for traffic signal use. This is more loss in energy -LED’s make coloured light that does NOT have to be filtered; all the energy is concentrated around ONE colour band and the energy isn’t used up for others

3. When and Why Are LED’s Used? LED lights use less energy to operate than other light bulbs -due to the point above, money is saved on lighting light is much more vibrant, and the colors much more realistic they are more stable in power surges or power fluctuations -LEDs will give immediate light that can withstand just about any alteration in power -other bulbs are less efficient when the light is turned on and off which can cause them (esp. incandescent) to burn out LEDs are the most durable artificial light available -they are made out of shatterproof plastics & aircraft grade aluminum -therefore they survive trauma (ex: being dropped) LEDs last longer -they have a longer life span than other bulbs (less replacing them throughout the home) -most LEDs can be left on 24 hrs and last 10 years (but we really shouldn’t do that) where others would get too hot and burn out

4. THEREFORE…. • LEDs can be used for events where the lights have to sustain their light for a long time • For example: A night club could use LEDs to produce colourful flashing lights while saving money and having them stay on all night without losing their vibrancy. • When the lights need to be dimmed LEDs are used For example: When on a date and you want to turn down the lights OR in a movie theatre and the main lights need to be turned down so people can still see their hands but can focus on the movie. • LEDs can be used on a regular basis to light every room in the house! • -Your parents won’t have to change them as often and will be saving money • LEDs can be used during the Christmas season -Having those Christmas lights on can get expensive and will waste a lot of energy. Switching to LED will be more energy efficient and last a few more years than those old Christmas lights.

5. How and Where are LEDs used? LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Light-emitting diodes are used in applications as replacements for aviation lighting, automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The compact size, switching speed, and extreme reliability of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances.

6. Applications • LED lights have many applications. They are used in night lighting, art lighting, porch and outdoor lighting. top-floor observation deck of the Rockefeller Center in New York • Also, mp3 players, DVD players, computers and televisions use LEDs. There are versions of LED bulbs that can be used and tend to be more expensive. • Newer flashlights use LED technology because of its ability to easily be directed in steady streams. LEDs are beginning to get use in the traffic lights and outdoor signs of some cities. Many car manufacturers are beginning to use LEDs for their headlights.