LEDs, or light emitting diodes are tiny,
almost microscopic, chips of crystalline semiconductor material encapsulated
in solid epoxy, gum-drop-shaped packages. They are low voltage devices,
typically in the range of 1.7 to 4.2 volts DC.
LEDs do not have filaments like a conventional incandescent light bulbs.
They are not made of glass. They do not encapsulate a vacuum or inert gas.
They are not fragile and if powered properly, they do not fail instantly
The color of light that an LED produces is a result of the electro-chemical
properties of the crystalline structure of the diode chip inside.
The energies radiated from these chips are very narrow portions of the
visible light spectrum (the rainbow) therefore they appear to be nearly pure hues.
LEDs produce no noticeable heat and pose no fire or electrical shock hazard at all.
LEDs are considered to be semi-permanent devices. They are designed to have a
half-life of typically 100,000 hours or more. In other words, if lit continuously
for over 11 years, an LED might lose half of its brightness when new, but still be lit!
The technology that makes the new LEDs "super-bright" and capable of colors
like true green, turquoise, blue, violet and white has only been developed in the past
few years and literally every month brings the possibility of new exciting breakthroughs.
It is inevitable that LED technology will, for the most part, replace incandescent
and fluorescent lighting for interior illumination in the coming years.
LED are, already in wide spread use as yellow and red tail lights
on cars, trucks and busses and in high intensity traffic signals.