Film capacitor structure and basic characteristics of film capacitor

Introduction to film capacitors:

Due to the different capacitor dielectrics, the types of capacitors are also different. For example: paper capacitors, electrolytic capacitors, film capacitors, air capacitors and so on. Film capacitors are widely used in audio equipment, and are widely used in the cross-connection of analog signals.

Film capacitor structure:

The electrode of the film capacitor is made of metal foil. After overlapping it with plastics such as polyethylene, polystyrene, polypropylene, etc., they are rolled into a cylindrical shape to form a capacitor. Film capacitors can be divided into polyethylene capacitors, polystyrene capacitors, polypropylene capacitors and polycarbonate capacitors according to the types of plastic films.

Basic characteristics of film capacitors:

The film capacitor is a better capacitor because of its excellent characteristics. Its characteristics are: it has good insulation resistance; its dielectric loss is very small; and its frequency range is very wide. It is precisely because of these advantages that film capacitors are widely used in analog circuits.

The structure of film capacitors is the same as that of paper capacitors. Polyester or polystyrene is its dielectric. The dielectric loss of polystyrene capacitors is very small and has high insulation resistance, but it has a large temperature coefficient and can be used in high-frequency circuits. Polyester film capacitors are small in size, relatively large in capacity, and have good stability, making them more suitable for bypass capacitors.

The DC working voltage of the film capacitor is 63-500V, and the capacity range is 3pF-0.1μF, suitable for high frequency and low frequency.