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Internal structure of film capacitors

Release time:

2024-09-27

According to the capacitance formula, the size of the capacitance in addition to the capacitor specifications related to the thermal conductivity of the dielectric (Permittivity). The performance of the dielectric jeopardizes the performance of the capacitor, and different dielectrics are subject to different manufacturing processes.
For a comparison of the performance of common dielectrics, please refer to one of AVX's technical documents.
AVXDielectricComparisonChart (tips: apply Bing search, the first is)
Capacitor manufacturing processes can be divided into three main categories:
-FilmCapacitor.
-Electrolytic capacitors (ElectrolyticCapacitor) - Ceramic capacitors (CeramicCapacitor)
Film Capacitor (FilmCapacitor)
FilmCapacitor in China generally Chinese translation for film capacitors, but and ThinFilm processing is not the same. In order to distinguish, I think immediately translated into Chinese as film capacitor better. Film capacitor is based on the two pieces of plastic film containing metal material electrode inverted wire machine into a cylindrical shape, and ultimately sealed and molded; because its medium is generally plastic material, also known as plastic film capacitors;
Film capacitors can be divided into two categories according to the processing technology of its electrode:
Metal material foil film capacitors (Film/Foil)
Metallic foil film capacitors, immediately add a layer of thin metal material foil on the plastic film, generally aluminum platinum, as the electrode; this type of processing technology is relatively simple, the electrode is convenient to lead out, can be used in large electric flow places.
Metallized film capacitor (MetallizedFilm)
Metallized film capacitors, according to the vacuum pump stacking (VacuumDeposited) process immediately in the surface layer of the plastic film to produce a thin metal surface layer, as the electrode; because the electrode thickness is too thin, can be wound into a larger space capacitor; but because of the electrode is thin, thin, only applies to the small electric flow places.
Metallized film capacitor is to have its own repair function, that is, if the capacitor internal penetration destruction point, will cause avalanche effect in the destruction, vaporization of the metal material in the destruction will produce a vapor bonding surface, the short-circuit fault subsides, the destruction point is repaired; therefore, metallized film capacitor credibility is very high, there will be no short-circuit fault invalid; film capacitors have two kinds of rewinding machine: afterthought winding method in the pre rewinding machine In addition, there is also a laminated type of non-sensory capacitors, similar to the structure and MLCC, good performance, and is conducive to SMD packaging.
The use of the largest number of film capacitors is polyester film capacitors, more cost-effective, because of its high thermal conductivity, specifications can be made smaller; followed by polypropylene film capacitors. Other raw materials also have PTFE, polyethylene, polycarbonate these.