Light Emitting Diodes

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Light emitting diodes or LEDs are tiny bulbs that fit into an electric circuit. LEDs work by creating light without incandescence or florescence. Incandescent light bulbs use the process of passing an electric current through a filament, which is a thin, coiled wire. Florescent light bulbs are long white tubes, which produce light by chemical reactions in a system called gaseous discharge. LEDs are made of semiconductor material, which are materials that conduct current under some situations and not others. These chips have a semiconductor on one side that has extra electrons and a semiconductor on the other that is missing electrons. The side with the excess electrons is called N-type material because it has more negatively charged particles. The other side with the absent electrons has extra holes and is called P-type. It is called P-type because it had positivity charged particles. The two sides are stuck together and have electrodes placed at both ends. Then the entire chip is encased in a clear plastic container. When an electric current is administered to the LED, the free electrons from the N-type material move to fill the holes in the P-type material. While doing this they release photons, the fundamental particles of light. The arrangement of the semiconductors and electrodes conducts electricity in only one direction. The heat given off by LEDs is significantly less than have other light sources. The back of the unit is usually used to let the heat escape. Four independent American research groups invented light emitting diodes in 1962. They were introduced to be used as indicator lights and were red or amber. LEDs helped to solve many problems. One of these problems are that incandescent bulbs burn out too fast and get quite hot. LEDs on the other hand surpass the life span of an incandescent bulb by thousands of hours and they don’t get especially

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