Polyester film capacitors, also known as Mylar capacitors, are a popular choice, featuring polyester as their dielectric material. Available in both film and foil as well as metallized varieties, they offer an economical solution with voltage capacities ranging from 50VDC to 1000VDC.
The polyester capacitor is designed with two metal plates where the polyester film is arranged between them; otherwise, a metalized film can be placed over the insulator. The polyester capacitor capacitance ranges from 1nF -15µF and works from 50 to 1500V.
In comparison, polypropylene metallized film capacitors and double-sided metallized film capacitors have a self-healing property, and they are suitable for use in low pulse and medium pulse applications. These two types of capacitors are suitable for protecting various switching devices including thyristors, FETs and IGBT modules.
The most common dielectric materials used in the construction of plastic film capacitors are polypropylene and polyester.
Polypropylene film/foil capacitors are commonly used as snubber capacitors in low pulse applications. In comparison, polypropylene metallized film capacitors and double-sided metallized film capacitors have a self-healing property, and they are suitable for use in low pulse and medium pulse applications.
Polyester capacitors are available in the range 1nF to 15µF, and with working voltages from 50V to 1500V. They come with the tolerance ranges of 5%, 10%, and 20%. They have a high temperature coefficient. They have high isolation resistance, so they are good choice capacitors for coupling and/or storage applications.