A lighting ballast controls the starting and operating voltages of gaseous discharge lights. That type of lighting includes fluorescent, and high-intensity discharge (HID) lamps. Light bulbs in the gaseous discharge group do not have filaments and cannot regulate the amount of current passing through them. That function is performed by the ballast.
Magnetic lighting ballasts are obsolescent and are being phased out of service in most applications. Magnetic ballasts use a coil of wire and an electromagnetic field that together transform voltage and regulate the voltage. Magnetic ballasts for HID lighting may include an igniter to provide the starting voltage.
Magnetic ballasts do not change the frequency of the input power which may cause fluorescent lights to flicker and the ballast to hum.
Old Magnetic Ballasts
Old, magnetic ballasts may contain PCB. While this is not usually a threat to health and safety a leaking ballast can be a disposal nightmare. For more on the PCB issue go to our ballast recycling page.
Partially because of the hazardous material and partly because magnetic ballasts are less energy efficient than the electronic ballast that replaces them, the Department of Energy (DOE) Ballast Ruling of 2005 prevents the manufacture of T12 magnetic replacement ballasts after July 1, 2010.
T12 fluorescents are commonly four or eight feet long and 1.5 inches in diameter. If your ceiling has fixtures with T12 fluorescent light bulbs you are likely to have magnetic ballasts. Because of the magnetic ballast does not change the frequency of the electricity provided to the lamp the ballast is likely to produce a visible flicker and hum. To know for sure what kind of ballast your T12 lamps use you can do a physical inspection of each fixture or contact Service Lamp and ask about an Advance Ballast Checker.
A more modern type of lighting ballast is electronic instead of electromagnetic. An electronic lighting ballast uses solid state circuitry to transform voltage, but unlike electromagnetic ballasts, also alters the frequency of power. An electronic lighting ballast eliminates visible flicker in fluorescent lamps. Electronic ballasts are more efficient, use less energy and run cooler.
Because of their greater efficiency electronic ballasts are preferred over electromagnetic ballasts. Some applications, however, require an electromagnetic lighting ballast, such as ballasts that must preheat the lamp or ballasts for extremely high output lamps.
Some lamps come with a built-in electronic ballast. This is commonly seen in compact fluorescent lamps used in residential and hospitality applications. By having a built-in ballast and a medium base the compact fluorescent can directly replace incandescent lamps.
Philips introduced a self-ballasted, ceramic metal halide in 2005 that has the same form as a PAR38 halogen. At 23 watts, the "integrated" lamps are a direct replacement for a 75 watt halogen. Saving 52 watts per socket can be a significant dollar amount in retail settings.
For additional information or a quote for replacement ballasts call Service Lamp, 800-222-LAMP.