Detailed explanation of the basic knowledge of film capacitors

What is a film capacitor?

Film capacitors are also known as plastic film, polymer film, or film dielectric capacitors. Film capacitors are inexpensive and come with a nearly limitless shelf life. The film capacitor uses a thin dielectric material with the other side of the capacitor metalized. Depending on the application, the film capacitor is rolled into thin films.

What is a film capacitor value?

Film Capacitor Values are marked on it in terms of picofarads. Let us consider an example of the ‘Mylar Film Capacitor’. The markings of this capacitor are made in the center of it. 683 indicates the value of the ‘capacitance’ in picofarads. The third digit acts as the ‘Multiplier’. That is the value of this capacitor is 68,000 picofarads.

How to choose a film capacitor?

A Film Capacitor can be chosen its film based on the requirement of stability and where the cost is concerned. A capacitor whose dielectric is chosen is of the ‘Film’ type. This type posses stable behavior, low manufacturing cost. These types of capacitors are defined as film capacitors.

How do metalized film capacitors work?

The electrodes of metalized film capacitors consist of an extremely thin metal layer (0.02 μm to 0.1 μm) that is vacuum deposited either onto the dielectric film or onto a carrier film. The opposing and extended metalized film layers of the wound capacitor element are connected to one another by flame spraying different metals to the end-faces.

How reliable are film capacitors?

The most important reliability feature of film capacitors is their self-healing capability, i.e. their abil-ity to clear faults (such as pores or impurities in the film) under the influence of a voltage. The metal coatings, vacuum-deposited directly onto the plastic film, are only 20 ... 50 nm thick.

What does 'no indication' mean on a film capacitor?

As noticed on the capacitor consists of ‘no indication’ represents that Film Capacitors are non-polarized. There are various applications in which these capacitors are used. The ‘Power Film Capacitors’ is utilized in the Electronic Devices where power is the major concern in the flashes of ‘X-Rays’, Analog to Digital Converters … these are used.