THE CAPACITORS WITH ORGANIC FILM DIELECTRIC
find use in different electrotechnical devices, their electrical and operational parameters and characteristics are satisfied to wide range of users' demands. Main advantages of film capacitors are their high stable characteristics and relatively small dimensions.
The film capacitors are indispensable when it is necessary to realize such specific parameters as small charge absorption, extremely long time constant, increased capacitance stability, low losses in wide frequency range. Main areas of applications of these capacitors are radio and TV equipment, audio recording and reproducing devices, measurement systems and others.
The capacitors with organic film dielectric are applied in phase shifting elements in AC motors and as capacitive filters for EMI suppression.
Organic film dielectrics are widely used also in high energy storage pulse capacitors and in capacitors with increased reactive power designed for use in low- and high-frequency AC voltage circuits.
The capacitors with organic dielectric are divided into three main groups:
* capacitors based on low-frequency polar isolator - polyethylene terephtalate film;
* capacitors based on high-frequency nonpolar isolator - polypropylene film;
* capacitors based on composed dielectric: capacitor paper + film.
Organic film capacitor cover wide range of demands due to the characteristics of dielectrics used and also due to constructional and technological special features of the capacitors which are produced by mechanical winding of long and thin tapes of organic film dielectric with metallized film or foil electrodes which together constitute capacitor elements.
Organic film capacitor do not contain any precious metals and they are easy to produce. That is why a price of the capacitors wich are produced with good level of mechanization is not so high.
Conventional symbols on diagrams:
Cr - rated capacitance;
Ur - rated voltage