一, Film capacitor
A film capacitor is a capacitor in which metal foil is used as an electrode, and plastic films such as polyethylene, polypropylene, polystyrene or polycarbonate are overlapped from both ends and then wound into a cylindrical structure. According to the type of plastic film, they are called polyethylene capacitors (also known as Mylar capacitors), polypropylene capacitors (also known as PP capacitors), polystyrene capacitors (also known as PS capacitors) and polycarbonate capacitors.
二, the working principle of the film capacitor
The working principle of the film capacitor is the same as that of the general capacitor. It stores the electric charge on the electrode and stores the electric energy. Usually, it is used together with the inductor to form the LC oscillating circuit. The working principle of the capacitor is that the electric charge will move under the electric field, when the conductor Having a medium between them hinders the movement of charge and causes the charge to accumulate on the conductor, resulting in the accumulation of charge.
三, the use of film capacitors
The function of the film capacitor is the same as that of all capacitors, which acts to accommodate the charge.
However, compared with other general capacitors, film capacitors are excellent in performance because of their excellent characteristics. Its main characteristics are as follows: no polarity, high insulation resistance, excellent frequency characteristics (wide frequency response), and low dielectric loss.
A capacitor of the type of a metallized film, which has a so-called self-recovery effect (Self Healing AcTIon), that is, an electrode metal around the short-circuited portion is caused by a small portion of the electrode due to a weak electrical boundary. The electrostatic energy or short-circuit current carried by the capacitor at that time will cause a larger area of melting and evaporation to restore the insulation, so that the capacitor restores the function of the capacitor again. In other words, it can heal itself instantly.
Film capacitors are commonly used for high frequency filtering, high frequency bypass, first or second order filtering circuits. Widely used in electronics, home appliances, telecommunications, electric power, electrified railways, hybrid vehicles, wind power, solar power and many other industries.
