Purpose of a Ballast - Advance Transformer Ballast Mfg. The amount of light generated depends upon the amount of electrical current that passes through the filament. In addition to producing light, the filament also limits the current to safe operating values.
Fluorescent lamps are much more efficient than incandescent lamps in using energy to create light.
Rather than using a wire filament, their operation relies upon an electrical arc passing between two electrodes, one at either end of the lamp. Unlike incandescent lamps, fluorescent lamps cannot be connected directly to the power line. Unless the flow of current is somehow stabilized, more and more current will rush through the lamp until it overheats and destroys itself. The length and diameter of an incandescent lamp's filament wire limits the amount of electrical current passing through the lamp and regulates its light output. Fluorescent lamps sold in the US today are available in a wide variety of shapes and sizes.