A film capacitor is a capacitor constructed by using a metal foil as the electrode and overlapping it with a plastic film such as polyethylene, polypropylene, polystyrene or polycarbonate from both ends and then winding it into a cylinder. Depending on the type of plastic film, they are called polyethylene-based capacitors (also known as Mylar capacitors), polypropylene capacitors (also known as PP capacitors), polystyrene capacitors (also known as PS capacitors), and polycarbonate capacitors.