Information about LIGHT EMITTING DIODE (LED)

Published on April 13, 2012

Author: 3nathpandu



LED: LED LIGHT EMITTING DIODE PowerPoint Presentation: W hat is LED ??? ABBREVIATIONS NOT ALLOWED GO... PowerPoint Presentation: Light Emitting Diodes , commonly called LEDs, are real unsung heroes in the electronics world. They do dozens of different jobs and are found in all kinds of devices. Among other things, they form numbers on digital clocks , transmit information from remote controls, light up watches and tell you when your appliances are turned on. Collected together, they can form images on a jumbo television screen or illuminate a traffic light . PowerPoint Presentation: Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs , they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor. The lifespan of an LED surpasses the short life of an incandescent bulb by thousands of hours. Tiny LEDs are already replacing the tubes that light up LCD , HDTVs to make dramatically thinner televisions. What is happening??: What is happen ing?? The holes exist at a lower energy level than the free electrons. A n electron releases energy when it drops from a higher orbital to a lower one. This energy is released in the form of a photon . The energy is emitted in the form of light photon. The size of the electrons fall determines the energy level of the photon, which determines its color. A bigger fall produces a photon with a higher energy level and therefore a higher light frequency. DIODE Vs LED: DIOD E Vs L E D In an ordinary diode, the semiconductor material itself ends up absorbing a lot of the light energy. LEDs are specially constructed to release a large number of photons outward. They are housed in a plastic bulb that concentrates the light in a particular direction. INFRARED LEDs: I NFRA R ED LEDs You can only see the photons when the diode is composed of certain material. The atoms in a standard silicon diode , for example, are arranged in such a way that the electron drops a relatively short distance. As a result, the photon's frequency is so low that it is invisible to the human eye. I t is in the infrared portion of the light spectrum. Infrared LEDs are ideal for remote controls. VISIBLE LEDs: V ISIBLE LEDs Visible LEDs are made of materials characterized by a wider gap between the conduction band and the lower orbitals. The size of the gap determines the frequency of the photon . In other words, it determines the color of the light. Visible LEDs are growing in popularity and use thanks to their long lifetimes and miniature size. Depending on the materials used in LEDs, they can be built to shine in infrared, ultraviolet, and all the colors of the visible spectrum in between. @Rs:1/- : @Rs:1/- LEDs are available in red, orange, amber, yellow, green, blue and white. Blue and white LEDs are much more expensive than the other colors. The cost of manufacturing the product varies depending on the type of semi-conductor used. White LEDs are the most expensive because red, green, and blue are combined together to make a white LED. PowerPoint Presentation: THAN K YO U [email protected]

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