They incorporate the best features of fluorescent tubes - high efficiency and long life. Compact fluorescent lamps also have improved color characteristics and a compact size. The result is a variety of products that replace common standard incandescent bulbs and consume only one-fourth the energy. The ballast is an electric device required to start and operate the bulb. Compact fluorescent lamps come in two basic configurations.
Modular units contain a screw-in base and a replaceable bulb.
The base houses the ballast. The bulb can be replaced when needed for a fraction of the cost of the original unit. Modular compact fluorescent lamps tend to be larger and heavier than standard incandescent. Integral compact fluorescent lamps contain the bulb and ballast in a self-contained package. They are smaller and lighter than modular units.