What are film capacitors?

A film capacitor is a capacitor that uses polymer film as the dielectric. It is one recent example of a component that uses metalized film with the internal electrodes deposited to the film. Film capacitors can be classified by their structures and the types of dielectrics they contain. The main types of film capacitor structures are winded and layered. Winded film capacitors contain a polymer film that is wound and pressed, and inserted into a case. Layered film capacitors contain multiple layers of polymer film inserted into a case. Winded film capacitors are most commonly used now, as they have a simple structure.

Various polymer materials are used for film capacitor dielectrics, including PP, PET, PEN, and PPS. The characteristics of a film capacitor, and the situations in which the capacitor can be used, will vary greatly depending on the type of dielectric used. For example, a PP film capacitor provides excellent self-healing and high reliability, and is therefore often used in fields such as vehicle-mounted equipment and industry automation.