Film capacitor classification

Film capacitor is a kind of capacitor with metal foil as electrode, and plastic film such as polyethyl ester, polypropylene, polystyrene or polycarbonate, overlapped from two ends, and wound into a cylindrical structure。According to the type of plastic film, they are called polyethyl (Mylar) capacitors, polypropylene (PP) capacitors, polystyrene (PS) capacitors, and polycarbonate capacitors.

According to the film classification can be divided into about four types, which are:

1. Polyethyl ester capacitor ( Mylar capacitor)
2. Polypropylene capacitors ( PP capacitors), CBB belongs to this category
3. Polystyrene capacitor ( PS capacitor)
4. Polycarbonate capacitor

These capacitor structures are roughly similar to paper capacitors. Most of them are made of polystyrene and other materials. These thin film capacitors are characterized by good stability, small volume and large capacity, and are often used as bypass capacitors in circuits.

The performance of PP capacitor and PS capacitor is the best in many film capacitors, of course, PP capacitor and PS capacitor is also the most expensive capacitor of all film capacitors.

Characteristics of film capacitor 

Film capacitor is a kind of capacitor with excellent performance due to its many excellent properties. With the advantages of Non-polar, high insulation impedance, excellent frequency characteristics (wide frequency response), and low dielectric loss, film capacitors are widely used in analog circuits.Especially in the part of the signal intersection, it is necessary to use capacitors with good frequency characteristics and very low dielectric loss to ensure that the signal will not have too much distortion during transmission.Among all the plastic film capacitors, polypropylene (PP) capacitor and polystyrene (PS) capacitor have the most prominent characteristics, of course, the price of these two capacitors is also relatively high.In recent years, in order to improve the sound quality of audio equipment, the use of parts and materials has become more and more advanced, price is not the most important factor to consider, so in recent years PP capacitance and PS capacitance are used in audio equipment frequency and quantity is also increasingly high.

Advantages of film capacitor

The main advantages of film capacitance: high insulation resistance, good heat resistance. It has self - healing and non - sensory properties.It has excellent high-frequency insulation performance, and the capacitance and loss Angle are independent of frequency in a large frequency range, and the change with temperature is very small, while the dielectric strength increases with the increase of temperature, which is difficult for other medium materials to have. High temperature resistance and low absorption coefficient.

Structure diagram of the film capacitance