What is the difference between wound and laminated film capacitors? Introduction to the structure of film capacitors



If divided according to the internal structure of film capacitors, we can divide film capacitors into winding structure and laminated structure. If you have not seen the production process of film capacitors, it is difficult to imagine the difference between them.

The roll-to-roll type is a structure in which a polymer film is wound and punched, and then packed into a shell. The laminated type is a structure in which multiple polymer films are laminated together, and then the laminated body is housed in a case.

Most of the film capacitors now basically have a winding internal structure. Its advantages are easy to manufacture, and wound film capacitors are currently the most commonly used type.

Film capacitors with a laminated structure, such as CL71 correction capacitors, are widely used. However, the production equipment of this type of capacitor is complex and extremely expensive, and the product defect rate is relatively high. Now it is slowly being replaced by CL23B winding correction capacitors. Yes, true laminated film capacitors are now rarely seen.

The quality of film capacitors is closely related to the quality of film materials, not closely related to the internal structure

The process flow of thin film capacitors can be simply summarized as follows: deposit a layer of metallized film on the base film, then cut the metallized film according to certain specifications, wind it, weld the leads at both ends, and then put it into the case. Among them, the thickness, material, and pattern of the metallized film determine the electrical characteristics and life of the thin film capacitor, so the metallized film is a decisive indicator for determining the performance of the thin film capacitor.

The price of film capacitors on the market varies greatly. To put it bluntly, the core is the difference in raw materials. If the raw materials used are extremely poor, the unit price is indeed very low, but the quality of film capacitors is very poor and the life is short. It can be understood in this way that film capacitors also pay for what you pay for, and the low unit price is achieved by manufacturers by cutting corners.

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