Film capacitor function and working principle

Film capacitors, also known as plastic film capacitors, refer to capacitors that use (electrical grade) plastic films as dielectrics. Compared with ceramics and electrolytic capacitors, it has the advantages of good product performance and high reliability, but the capacity/volume ratio is small and the price is high.

Film capacitor function:

The function of the film capacitor is the same as that of all capacitors, which acts to hold the charge. However, film capacitors are excellent in performance compared to other general capacitors 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.

The capacitor of the type of metallized film has a so-called self-healing action, that is, the electrode metal around the short-circuited portion is caused by a small portion of the electrode due to a weak electrical boundary. Due to the electrostatic energy or short-circuit current of the capacitor at that time, a larger area of melting and evaporation is initiated 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.

Film capacitor working principle:

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 an LC oscillating circuit. The working principle of the capacitor is that the electric charge will move under the electric field, when the conductor With a medium in between, the charge is prevented from moving and the charge is accumulated on the conductor, resulting in cumulative storage of the charge.

Film capacitor development:

The development direction of film capacitors is low cost, miniaturization, chip formation, ultra high pressure, high power, high precision and high reliability. With the application and development of new materials and new process technologies, film capacitors will undergo major changes. With the development of complete equipment, the application of film capacitors will bring opportunities and challenges.