Ballasts
Ballasts are used to control the start and voltages of electrical discharge lamps, such as HID and fluorescent lamps. These lamps are not able to regulate the flow of current, and require ballasts to provide resistance and limit the electrical draw, without which the lamp would continue to draw power until burning out. Although smaller lights can use simple ballasts, such as a series resistor, to regulate the current flow, more powerful lights will require a more complicated ballast.
