It is a type of film capacitor, in this case polypropylene film, but first we have to know a little what a film capacitor or film capacitor is.
Film capacitors, plastic film capacitors, dielectric film capacitors or polymer film capacitors, generically called "film layers", as well as power film capacitors, are electrical capacitors with an insulating plastic film as a dielectric, sometimes combined with paper as a carrier for the electrodes. .
These dielectric films, depending on the desired maximum voltage or dielectric strength, are stretched in a special process to an extremely thin thickness and then electrodes are attached to them. The electrodes of the film capacitors can be metallized aluminum or zinc applied directly to the surface of the plastic film, or a separate metal foil. Two of these conductive layers are wound into a cylinder-shaped winding, generally flattened to reduce mounting space on a printed circuit board or pcb, or layered as multiple individual layers stacked together, to form a capacitor body.
A related type of component is the power (film) capacitor. Although the materials and construction techniques used for high-power film capacitors are very similar to those used for ordinary film capacitors, capacitors with high to very high power ratings for applications in power systems and electrical installations. they are often classified separately, for historical reasons. As modern electronic equipment has acquired the ability to handle power levels previously the exclusive domain of "electrical power" components, the distinction between "electronic" and "electrical" power classifications has become less clear
Film capacitors are the most common types of capacitors and it belongs to a relatively large family of capacitors. The main difference between film capacitors and other types of capacitors lies in their dielectric properties. Some are listed below and to their left their different most common trade names:
They are available in many values, tolerances from 10% to 0.01% and voltages up to 2000 volts.
Specifically, polypropylene film capacitors have a dielectric made of thermoplastic, nonpolar, organic and partially crystalline polymeric material Polypropylene (PP), trade name Treofan, from the polyolefin family. They are manufactured in both rolled and stacked metallized versions, as well as in film / foil. Polypropylene film is the most widely used dielectric film in industrial capacitors and also in types of power capacitors. Polypropylene film material absorbs less moisture than polyester film and is therefore also suitable for "bare" designs without any additional coating or packaging. But the maximum temperature of 105 ° C makes it difficult to use PP films in SMD packaging.
The temperature and frequency dependencies of the electrical parameters of polypropylene film capacitors are very low. Polypropylene film capacitors have a linear negative temperature capacitance coefficient of ± 2.5% within their temperature range. Therefore, polypropylene film capacitors are suitable for applications in Class 1 frequency determination circuits, filters, oscillator circuits, audio circuits, and timers. They are also useful for inductive coil compensation in precision filter applications and for high frequency applications.
In addition to the application class rating for the film / foil version of PP film capacitors, the IEC / EN 60384-13 standard specifies three "stability classes". These stability classes specify the tolerance on temperature coefficients along with the allowable change in capacitance after defined tests.