Electronic ballasts produce light more efficiently and are quieter than magnetic ballasts. They are up to 25% more efficient than magnetic ballasts. Electronic ballasts can operate from one to four lamps at a time. Most commonly used for T5, T8, and T12 fluorescents. Over time, electronic ballasts will replace magnetic ballasts entirely. Electronic ballasts usually change the frequency of the power from the standard mains frequency of 50 - 60 Hz to 20,000 Hz or higher.
Magnetic ballasts are also called inductive or electromagnetic ballasts. Although magnetic ballasts are still very common, over the next several years manufactures will begin to phase out magnetic ballasts for electronic ballasts. Magnetic ballasts operate T12 lamps (including bi-pin, single-pin, and high output), some T8 lamps, and 2-pin compact fluorescent lamps. Magnetic ballasts are available in 1 and 2 lamp configurations.