LEDs are commonly used in all kinds of applications. The tiny
red and green indication lights found here and there on
electronic equipment such as TVs and computers are LEDs. They
are very efficient in converting an electric current directly
into light, but their use was limited by technical constraints
preventing the creation of colors other than red and green. In
the 1990s, LED color display was made possible by the
development of blue LEDs, and we are now witnessing rapid growth
in LED applications. The outdoor displays you see on the sides
of buildings and other locations on city streets use LEDs. They
are also employed in the optical scanning units of color copying
machines and image scanners. Mechanism by Which Light Exposure
Produces an Electric Current To understand LEDs, let's first
take a look at the mechanism by which light exposure produces an
electric current, such as in solar batteries. Semiconductors, a
term you probably hear daily, are a key component of electric
circuits, including computers,