Vapor's Influence on Film Capacitors

Film capacitors have high insulation resistance, excellent frequency characteristics (broad frequency response), and very little dielectric loss. In the process of using film capacitors, there is an inevitable situation that will occur to the capacitor, that is, the capacitance of film capacitors will decay. This article will talk about how the vapor affects the capacitance of film capacitors.

The reason why the water vapor in the film will cause the capacitance attenuation of the film capacitor is that when the capacitor is working, the air may be ionized under the action of the electric field. Ozone is generated after air ionization. As we all know, ozone is a strong oxidant. The metal coating of the metallized film (the composition is Zn/Al) oxidizes immediately after encountering the oxygen decomposed by ozone to form a transparent and non-conductive metal oxide ZnO And Al2O3, the actual performance is that the area of the plate decreases, and the capacitance of the capacitor decreases.

Therefore, eliminating or reducing the air between the membrane layers (especially the humid air. Because when the air between the membrane layers is invaded by external water vapor, the breakdown potential of the air will drop, speed up the ionization of the air, and generate a large amount of ozone) can slow down the decrease of capacitance. The entry of water vapor will cause the capacitance attenuation of the film capacitor, so it is very important to choose a regular and experienced manufacturer.

JYH HSU(JEC) Electronics Ltd (or Dongguan Zhixu Electronic Co., Ltd.) has engaged in the electronic component industry for many years, and our technical engineers can help you solve related problems. When purchasing varistors, you need to find out whether the products come from regular manufacturers. A good varistor manufacturer can reduce many unnecessary troubles.

JEC has over 30 years of manufacturing experience in the electronic components industry. If you have technical questions or need samples, please contact us.