Compact Fluorescent Light (CFL) bulbs are a fluorescent lamp designed to replace incandescent light bulbs. They use a curved or folded tube to fit into a standard light fixture, and a compact electronic ballast in the lamp base.
To learn more check out our informative Light Bulb Buying Guide.
These lamps contain electrons that are bound to atoms which are excited to states where ultraviolet light is emitted. The ultraviolet light is then turned into visible light when it strikes the fluorescent coating. These CFLs are about 80% more efficient than incandescent globes but have some restrictions such as dimming size and appearance.