compact fluorescent lamp

A compact fluorescent lamp (CFL) is an energy-efficient type of electric discharge lamp that produces light through the fluorescence of a phosphor coating. It uses significantly less electricity than traditional incandescent bulbs, consuming only about a quarter of the power.

CFLs consist of a glass tube filled with argon and mercury vapor. When an electric current passes through this mixture, it emits ultraviolet radiation. This radiation is then absorbed by phosphors on the inside of the tube, causing them to glow and emit visible light.

Unlike older fluorescent lamps, CFLs have the ballast integrated into the base of the bulb, often in a coiled shape resembling an incandescent bulb. This design reduces or eliminates the buzzing sound common in older models and makes them suitable for standard household fixtures. While the initial cost of a CFL may be higher due to the ballast, its lower energy consumption and longer lifespan result in overall cost savings for consumers. CFLs are rated by their energy use in watts and light output in lumens.123