Ballasts and drivers are components that regulate the current and voltage going to the light bulbs or LED arrays in lighting fixtures. They guard light bulbs and LED arrays from power supply fluctuations that can degrade the quality of the bulbs' and arrays' light output. HID ballasts and fluorescent ballasts both turn on fluorescent or HID light bulbs with a high voltage spike and then regulate the current to the bulbs for as long as the fixture is turned on. To power LED light bulbs and fixture arrays, LED drivers convert high-voltage alternating current (AC) into low-voltage direct current (DC).