Film capacitors are one of the most common types of capacitors used in electronics systems today. The most widely used types of film capacitors include polyester, polycarbonate, polystyrene, polypropylene, polysulfone, and Teflon capacitors. A comparison chart of various film capacitors is shown in Table 1.
In conclusion, capacitor manufacturing has seen significant advancements in recent years, with leading brands like Cornell Dubilier, Panasonic, and Murata at the forefront. These manufacturers offer a wide range of capacitors suitable for various applications.
Although the materials and construction techniques used for large power film capacitors are very similar to those used for ordinary film capacitors, capacitors with high to very high power ratings for applications in power systems and electrical installations are often classified separately, for historical reasons.
The inherent geometry of film capacitor structure results in very low ohmic losses and a very low parasitic inductance, which makes them especially suitable for applications with very high surge currents (snubbers) and for AC power applications, or for applications at higher frequencies.
Even the long-time manufactured polystyrene (PS) and polycarbonate (PC) film capacitors have been largely replaced by the previously mentioned film types, though at least one PC capacitor manufacturer retains the ability to make its own films from raw polycarbonate feedstock.
Especially for applications with high current pulse loads or high AC loads in electrical systems, heavy-duty film capacitors, here called "power capacitors", are available with dielectric ratings of several kilovolts. But the manufacture of film capacitors does have a critical dependency on the materials supply chain.