What is film capacitors？Film capacitors, which are also known as plastic film capacitors. They take the plastic film as the dielectric.
Basic profile of film capacitors:According to the different media, there are many different types of capacitors.For example, electrolytic capacitors, paper capacitors, film capacitors, ceramic capacitors, mica capacitors, air capacitors, etc..But the use of the most frequent in the audio equipment, is the electrolytic capacitor and film (Film) capacitors. Electrolytic capacitors are mostly used in a large amount of power, such as the main power part of the filter capacitor, in addition to filtering, and also to do with the storage of electricity. While the thin film capacitors are widely used in analog signals, power supply noise bypass (reverse link) and other places.
The film capacitors take metal foil as electrode,it and poly ethyl ester, polypropylene, polystyrene or polycarbonate and other plastic film, from the ends of the overlap, winding into a cylindrical structure of the capacitor.And the type of plastic film is called the poly (ethyl ester capacitor (also known as Mylar capacitor), polypropylene capacitor (also known as PP capacitor), polystyrene capacitor (also known as PS capacitor) and poly carbonate capacitors.
The film capacitors have many excellent properties,so they are excellent capacitors.Their main characteristics are as follows: polarity, high insulation resistance, excellent frequency characteristics (frequency response), and the medium loss is very small.Based on the above advantages, it is widely used in analog circuit.Especially in the part of signal connection, we must use such a capacitor: its frequency characteristic is good, the medium loss is extremely low. It is able to ensure that the signal is transmitted without much distortion.
Structure of the film capacitors and paper capacitors is same.Medium is polyester or polystyrene, etc.. Polyester film capacitor, the dielectric constant is higher, the volume is small, the capacity is large, the stability is relatively good, it is suitable as a bypass capacitor. Polystyrene film capacitor, its dielectric loss is small, the insulation resistance is high, but the temperature coefficient is large, it can be used for high frequency circuit.