Metalization is different from the structural structure of the foil film. Teach you how to choose here. For metallized thin film capacitors, aluminum is sprayed into the dielectric film by film vacuum deposition. The metallization is smaller than the capacitor made of separate foil and membrane layer, the weight is lighter, and the cost of the unit Fala is lower, and it is healing. But it also causes a lower current capacity. Smaller size and low costs are particularly attractive in high power capacity

 

Self-healing refers to an internal short circuit or a defect in the membrane from the transient overvoltage to be removed in a few microfarad. This is a small fault in an external voltage, but the capacitor does not have permanent damage to avoid negligible capacitance decrease. This advantage makes the HVC metallic film capacitor becomes the correct high selection in the application, but the following four cases exception:

1) Small capacitance less than 0.01 μF, in which the size difference is not important, and the foil film material is smaller.
2) Like a high continuous current in the volatile circuit,
3) Like the high transient current in the abruptive loop,
4) Low noise, there is a problem in this self-cleaning, although little is accompanied by noise voltage

 

Polyester dielectric: as metallization is usually the selection of HVC structures, and the polyester is typically the selection of dielectric film materials. In three HVC dielectrics, polyester has the highest dielectric constant, providing the lowest cost minimum size capacitor, and the advantage of operating at a temperature of up to 125 ° C at half rated voltage. However, as the power dissipation hinders its choice as a high current or high frequency AC voltage, the power dissipation hinders its application in high current or high frequency AC voltage; from -55 ° C to 0 ° as capacitance C and from 50 ° C to 125 ° C, polyester is not a precise capacitance at extreme temperatures. However, it is noted that the capacitance from 0 ° C to 50 ° C is only changed for ± 1%.

 

Polypropylene dielectric is based on its lower loss angle that the HVC capacitor can be eligible for DC high current, AC high voltage and communication high frequency applications. At the same time, its high insulating resistors and low dielectric absorption meet the precise DC capacitor. In many applications, it will replace polyester, except for its low dielectric constant; because thin high ratio foil film is not obtained, the size is large and higher. It is a bad thing that the maximum operating temperature is 105 ° C. Polypropylene is suitable for applications where many polyesters are lacking. It can even make up the polyester can be used on a wide temperature: its capacitor is about the same rate as the temperature drop is increased. Therefore, the polypropylene capacitor parallel polyester capacitance forms a temperature compensation capacitor.

 

Polyphenylene sulfide is used in precise capacitance and width temperature. It can operate from -55 ° C to 125 ° C, mostly the capacity of less than 1%, except for the range extreme value. Polyphenylene sulfide is the preferred precise capacitor dielectric and a dielectric film of the FCP chip capacitor.

 

Dielectric comparison chart: