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Light emitting diodes (LEDs) generate sharp, focused light.

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Light Emitting Diodes (LEDs)

Light emitting diodes (LEDs) generate sharp, focused light.

To generate this light, these highly efficient sources rely on layers of elemental material such as indium, gallium and aluminum. Applications include DVD technology, traffic lights and stadium scoreboards. (Photo: iStock.com/Tihis)

(Courtesy of iStock.com/Tihis)