Technical Info - LEDs

LED's are a special diode that emit light when connected to a battery. Each LED has a semi-conductor "chip" inside of it. When an electrical voltage is applied, the electrons will only flow in one direction and when the jump across the chip they are attracted to other positively charged particles. When a negative and positive charge are combined a "quantum" of energy is emitted in the form of a "photon" of light. The color of the LED light that is emitted is a result of what the chip is made of (typically the elements gallium, arsenic, and phosphorus).

We may be going through a memorial time in history right now. LED's may soon replace the regular lights (called incandescent lights) that Thomas Edison invented 100 years ago. If you pay attention you may notice that things such as LED flashlights are beginning to become popular. Many traffic stoplights are now built using LED's (the LED stoplights are the bright ones that look like they're made of many small light bulbs). LED's are much more durable that incandescent lights, they are brighter, they don't get as hot, and they use less battery power. The light is a very bright, white light instead of the yellowish color we see with regular light bulbs. And best of all - they last a LONG time! A typical traffic stop light burns out once a year. LED stoplights are expected to last up to 10 years!

Pay attention to the various types of lights around you and you'll begin to notice more and more of these lights being replaced with LED lights. Car manufacturers are beginning to use them in the brake lights of new cars. TV monitors are starting to use LED lights. Neon signs are being replaced with LED signs. Even the Jefferson Memorial in Washington D.C. is now lit with LED lights. As the chips used in the lights become cheaper and scientists figure out easier ways to build them, we'll see LED's used more and more in place of ordinary light. - from Encarta 2003 and Discover Magazine