A ballast is a device that is used in fluorescent, HID, and some LED lamps to regulate the current to the lamp and to provide enough voltage to start the lamp. It is placed in series with the lamp to limit the amount of current in an electrical circuit. The ballast interacts with the lighting mechanism to control, regulate, and ultimately stabilize the light output of the lamp. It has two main functions: to start the lamp and to control lamp operation. The ballast ensures that a lamp stays lit by managing the distribution of energy throughout the fixture. There are many different types of ballasts, including electronic ballasts and magnetic ballasts. The type of ballast needed depends on the conditions in which the lighting system operates and the type, length, and wattage of the tube. Without a ballast, the fluorescent lamp would uncontrollably increase the amount of current it draws from the power source, causing it to overheat and burn out within a second.