Characteristics and Functions of Film Capacitors

May. 29, 2024

Film capacitors use metal foil as electrodes, which are layered with plastic films such as polyethylene, polypropylene, polystyrene, or polycarbonate, and then wound into a cylindrical shape. Due to their many excellent characteristics, film capacitors are considered high-performance capacitors.


Their main characteristics are as follows: they are non-polar, have very high insulation resistance, excellent frequency characteristics, and very low dielectric loss. Due to these advantages, film capacitors are extensively used in analog circuits. Particularly in signal coupling sections, capacitors with good frequency characteristics and very low dielectric loss must be used to ensure minimal signal distortion during transmission. Film capacitors are generally used in high-frequency filtering, high-frequency bypass, and first-order or second-order filtering circuits.


Characteristics and Functions of Film Capacitors

The function of film capacitors, like all capacitors, is to store electric charge. Film capacitors are widely used in various industries including electronics, home appliances, communications, power, electrified railways, hybrid vehicles, wind power generation, and solar power generation.


Among these, metallized film capacitors have a so-called self-healing property. If a small part of the electrode short circuits due to dielectric weakness, the surrounding electrode metal will melt and evaporate due to the electrostatic energy or short-circuit current at that moment, restoring the insulation and allowing the capacitor to resume its function. This means they can self-heal instantaneously.


This article is provided by JYH HSU (JEC) Electronics. JEC is a research, development, production, and sales-oriented company specializing in manufacturing and selling various electronic components such as capacitors and resistors.

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