LED : Computer Hardware Buyers’ Glossary

LED (Light-Emitting Diode). LEDs are those tiny bright lights that never burn out you see on computer panels, home stereos and kitchen appliances. The are much more efficient than incandescent bulbs. They don’t waste most of the power as heat. They now come in many colours including red, blue, green, yellow, violet, orange and many shades of white. They need low DC voltages to run, so you can’t run them directly off the AC (Alternating Current) mains. You need a transformer, USB (Universal Serial Bus) port or battery to provide the power. They are now used for home lighting, desk lamps, SAD (Seasonal Affective Disorder) lamps, street lamps, stop lights, Christmas tree lights, grow lights… They are actually a type of semiconductor diode. The amount of light is proportional to the area of the diode, so they can be made pretty well as bright as you need. They are polar, so it matters which lead you attach to the positive voltage supply.

Fluoresents and halogen bulbs are still more efficient than LED s, though LEDs are rapidly gaining on them. LEDs are more efficient than incandescents. In displays, LCD (Liquid Crystal Display) s are more efficient that LEDs since they don’t emit light, just reflect it. The big advantage LEDs have is durability and cool running temperature. This makes them safe for Christmas trees for example. I made a set circa 1973.