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• Fluorescent lamps require special auxiliary equipment to provide reliable starting and to assure proper electrical operation. The principle function of the ballast is to hold operating current within proper limits and to provide enough voltage to start the lamp.
• Instant-start ballasts provide sufficient voltage to start fluorescent lamps without preheating and are commonly used with single-pin lamps and some special lamp types.
• Rapid-start ballasts heat the cathodes continuously from a low-voltage transformer within the ballast. This is the most common type of ballast in use today for 40-watt lamps and for all lamps that use recessed double-contact bases.
• Reduced wattage lamps operate on most existing ballasts, which can reduce wattage 14 to 20 percent. In addition, new ballasts developed to minimize the wattage consumed by the ballast itself further reduce electrical consumption.