What are film capacitors?

Film capacitors are electronic capacitor devices typically made of polypropylene (PP) charged with electrodes. They feature two pieces of thin plastic films that act as the dielectric. Unlike electrolytic capacitors, film capacitors are non-polarised. They are extensively used in different types of electrical equipment and are capable of replacing electrolytic capacitors in certain applications where the voltage is more than 500V. 

Types of film capacitors

Film capacitors are mainly available in two different varieties, depending on the type of featured dielectric materials. The one you choose should depend on the required electrical characteristics demanded by the application, including stability, voltage capabilities, and so on. Film foil capacitors feature two plastic films separating two metal foil electrodes. Metallised film, on the other hand, features a plastic film and two thin layers of metals, and the former acts as the dielectric.

Applications

Polypropylene film capacitors possess a high tolerance and a higher voltage resistance. This makes them ideal for a multitude of electric applications. For example, they can be found in:

• High-voltage circuit applications 
• Switching power supplies 
• Lighting ballast systems 
• High peak current circuits