LEDs or Light Emitting Diodes are small lights that come in many different colours and sizes. They even emit infra-red and ultra-violet light.
LEDs are used in car lights, traffic signals, holiday lights, televisions and indicators to show something is switched on or off.\
More importantly, they have begun to be used as replacements for household lights for a number of reasons:
As a comparison:
|LED Light Bulb||CFL Light Bulb||Incandescent Light Bulb|
|Cost to run||$32 / year||$80 / year||$330 / year|
|Works in Cold Temperatures||Yes||No||Yes|
|Turns on instantly||Yes||No - has to warm up||Yes|
The long leg of the LED is called the anode or positive leg.
The short leg near the flat spot on the case is called the cathode or negative leg.