In all fluorescent lighting systems, the ballast performs three basic tasks:
- Provides the proper voltage to establish an arc between the electrodes.
- Regulates the electric current flowing through the lamp to stabilize light output.
- Supplies the correct operating voltage to provide the specified lamp operating current. Ballast map also compensate for supply voltage variations.
In rapid-start fluorescent systems, the ballast performs an additional function, providing continuous voltage to maintain heat in the lamp electrodes—at a level recommended by the lamp manufacturer during lamp operation. If electrode filaments of a rapid-start lamp are not continuously heated, they may deteriorate prematurely, shortening lamp life.