What are the advantages of film capacitors and how are they made?

Advantages and manufacturing methods of film capacitors

Since the film capacitor has many excellent characteristics, so it is a kind of capacitor with excellent performance.

Its main characteristics are as follows: non-polarity, high insulation resistance, excellent frequency characteristics (wide frequency response), and low dielectric loss. Based on the above advantages, film capacitors are widely used in analog circuits.

Especially in the signal cross-connection part, capacitors with good frequency characteristics and extremely low dielectric loss must be used to ensure that the signal is transmitted without too much distortion.Among all plastic film capacitors, polypropylene (PP) capacitors and polystyrene (PS) capacitors have the most remarkable characteristics. Of course, the prices of these two types of capacitors are relatively high. However, in order to improve the sound quality of audio equipment, the parts and materials used have become more and more advanced, and the price is not the most important consideration. Therefore, the frequency and quantity of PP capacitors and PS capacitors used in audio equipment are also increasing.

Readers can often see XX brand equipment, how many XX brand name PP capacitors or PS capacitors are used as the standard of sound quality, and the reason is here.

The general method of making film capacitors is to use aluminum and other metal foils as electrodes and plastic films to be overlapped and wound together. However, there is another manufacturing method for film capacitors, called metallized film. The method is to deposit a thin layer of metal on a plastic film by vacuum evaporation to serve as an electrode. In this way, the thickness of the electrode foil can be omitted, and the volume of the capacitor per unit capacity can be reduced. Therefore, the film capacitor can be easily made into a small and large-capacity capacitor.

For example, the common MKP capacitor is the code name for metallized polypropylene film capacitor, while MKT is the code name for metallized polyester capacitor.