Ballasts are electrical devices that convert line current into the proper voltage, amperage, and waveform to operate fluorescent lamps. The choice of ballast influences how efficiently a lighting system operates and how much light it provides, but users face an often bewildering array of options. The best choices are usually high-performance instant-start ballasts, unless lights aren’t switched on and off very often, in which case programmed rapid-start ballasts may be the best way to go. Dimming ballasts also offer savings opportunities in many situations.