About Film Capacitor

The Tecate line of film capacitors is comprehensive in it’s breadth and depth.  In addition to our vast line-up of catalog film capacitors, Tecate supports custom, application specific requirements as well. 

Film capacitors, as a category,  include any capacitor type made from plastic: polyester, polypropylene, polystyrene, etc. There are at least two types of film capacitors. Film-foil capacitors are constructed of layers (single or multiple) of plastic film dielectric wound alternately with metal foil electrodes. Metallized film capacitors are constructed of film dielectric on which the metal electrode has been previously vapor-deposited.  The layers are wound into a convoluted roll (jelly roll), with electrodes extending beyond the dielectric films.

Film capacitors are designed using a number of different dielectrics. Dielectrics are the insulating materials between the plates of the film capacitor. Materials are chosen for their ability to permit electrostatic attraction and repulsion to take place across the film.  Materials will have the property that energy required to establish an electric field is recoverable in whole or in part, as electric energy. In other words, good dielectric material is a poor conductor of electricity while being an effective supporter of electrostatic fields in film capacitors.  Common dielectrics used in film capacitors include polyester, polycarbonate, polypropylene and polystyrene. 

Polyester film capacitors offer a high dielectric constant and high dielectric strength with volumetric efficiency for metallized polyester film capacitors. Metallized polyester film has excellent self-healing properties. Typical applications include bypassing and coupling.

Polypropylene provides very low losses, low dielectric absorption, and high dielectric strength. In addition, polypropylene film capacitors offer very high insulation resistance and negative temperature coefficient. Typical applications include stable oscillators and filters, sample and hold circuits and pulse handle circuits.

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