A

David

Darling

ballast

electronic ballast

A ballast is a device used to start and thereafter control the voltage (or regulate the current) in a fluorescent lamp. The ballast efficacy factor, a measure of the efficiency of fluorescent lamp ballasts, is the relative light output divided by the power input. The ballast factor is the ratio of light output of a fluorescent lamp operated on a ballast to the light output of a lamp operated on a standard or reference ballast.