The interpretation of absorption coefficient of thin film capacitor

Film capacitors are ubiquitous in our lives. Its applications are very wide, such as our common air conditioners, refrigerators, washing machines, water heaters, etc. Today, Xiao Bian took everyone to know about the film capacitors, what is the absorption coefficient of the film capacitors? , The role of the film capacitance absorption coefficient and the occurrence of abnormal conditions. Follow the progress of Xiao Bian to learn about it!

A film capacitor is a type of capacitor in which a metal foil is used as an electrode, and a plastic film such as polyethylen, polypropylene, polystyrene, or polycarbonate is superposed on both ends and then wound into a cylindrical shape. The polypropylene's film capacitance has a very small absorption coefficient, its capacity and loss tangent tg σ change little with temperature, and its dielectric strength increases with temperature. This is one of his characteristics, which is difficult for Other Capacitors to have. . What is its absorption coefficient? This is the value used to describe the dielectric absorption phenomenon of the film capacitor. We call it the absorption coefficient, which is related to the three factors of dielectric, dielectric polarization, and capacitor absorption. This coefficient is not the same, different manufacturers, different models of batches will be different, even the same manufacturer model batch produced by each film capacitor may be different.

The dielectric absorption effect of the film capacitor determines the low-frequency characteristics of the capacitor. The smaller the absorption coefficient, the better the film capacitor and the faster the capacitor is charged and discharged. In the absolutely ideal state, if the absorption coefficient can be zero, the dielectric (ie, the insulator) has no polarization under the effect of the applied electric field, and the dielectric surface has no traction binding force on the charge, and the capacitor does not have hysteresis in the charge and discharge response. Of course, this is an ideal situation. In fact, the current technology cannot be realized.

If the absorption coefficient is too large, the charge/discharge response of the capacitor is seriously delayed, the time constant of the ultra-low frequency smoothing filter becomes large, the zero point of the DC amplifier is disturbed, and the unidirectional drift, the ripple of the power supply circuit, and the like will occur. Therefore, the film capacitance will occur. The smaller the absorption coefficient, the better.

After reading this article, everyone should understand what is the absorption coefficient of the thin film capacitor. If you have technical problems, you can contact us. We are here to answer your questions.