A Concise And Brief Explanation Of Film Foil Capacitor And Its Usage

Film capacitors also known as film dielectric capacitors are capacitors which use a thin plastic film as the dielectric. The electrode contained in film capacitors can be metalized aluminum or zinc and directly applied to the surface of the plastic film that is overlying the film. In contrast to non-inductive type capacitors, film foil capacitor can handle large voltage application. Here is the brief explanation of film capacitor and its different usage.

Characteristic of film foil capacitor:

Film foil capacitors are made with very high precision capacitance value and they can keep capacitance for a longer time which is even more than non-inductive type capacitors. This makes aging process is slower than in other capacitor. Moreover, film capacitors have low ESR (Equivalent Series Resistance), and low self-inductance (ESL) which results in very low dissipation factors. They are prone to burst into flames if overloaded. Though there are film capacitors which can withstand almost 200 volt-amps.

Use of film capacitor:

Film capacitors are the most widely used form of an electronic capacitor. Film capacitors have very low ESR and ESL values which make it well suited for many general purposes and industrial applications in electronic equipment. Film foil capacitors are not polarized hence they can be used in AC voltage application without DC bias and moreover they have very stable electrical parameters.

Different type of film capacitor and its usage:

Film capacitors are the most commonly available among all type of capacitors consisting of a relatively large family of capacitors. Depending upon shape and size film capacitors can be divided among the following type.

Radial lead type:

This type of film foil capacitors is made from a long thin strip of thin metal foil with the dielectric material sandwiched together. This is a form of box type capacitor because of its shape and it has two leads stick out from the bottom of the capacitor. It is highly different from axial capacitor because it has higher capacitance value. It is used in several DC to AC microelectronic and electronic application including motor run, snubbing and peak voltage detectors.

Axial lead type:

The axial capacitor is a typical film capacitor which has only one lead sticking out of each end. Axial type capacitor may be box type capacitor or it can be dielectric type capacitor. This type of capacitor is widely used because of its self-healing feature which makes it suitable for high power and more precise application.

So, from the above explanation, one can easily have a basic overview about the film foil capacitor.