Film Capacitors

B32656S8225K566 Application Field and Working Principle

A Film Capacitor, or sometimes known as an AC Capacitor, is an electrical components with two driving terminals, designed to store and deliver electrical energy. They are made up of two equal and parallel conductive plates, separated by a dielectric film also known as an insulator or dielectric. The dielectric material is usually a film of polypropylene, plastic or other non-conductive materials.

Application Fields

Film Capacitors are widely used in electric power industry, electrical appliance, communications, cars, medical equipment, etc. They are mounted between two wires to isolate them from each other. This helps protect the system from power surges and electromagnetic interference (EMI). They are also used to smooth out irregularities in power supplies. Film capacitors are used in charging and discharging circuits as well as in filter circuits to reduce noise and provide stabilization.

Film capacitors are used in high-frequency circuits and for decoupling in analog circuits. These capacitors are ideal for switching power supplies, rectifiers, frequency inverters and PLCs. They also protect devices that require low-voltage supply, such as microprocessors.

Working Principle

Film Capacitors work by trapping electrons between two conductive plates, which are held apart by a dielectric. When a voltage is applied to the capacitor, the electric field between the plates will start to increase, which affects the resistance and capacitance between the plates.

The capacitance of a capacitor is determined by the size of the plates and the dielectric material used. The thicker and more highly conductive the dielectric material is, the more capacitance the capacitor will have. This means that the smaller the capacitor, the more capacitance it will store. The capacitance of a film capacitor is usually low when compared to other types of capacitors, such as electrolytic capacitors.

When a current is passed through a film capacitor, the electrons will move from one plate to the other. This will create an electric field between the plates, which will be transferred to the outside of the capacitor. The current then returns to the source through the other plate.

Advantages

Film capacitors offer several advantages over other types of capacitors. They are smaller and more efficient than electrolytic or ceramic capacitors. They also offer excellent temperature stability, low ESR, and wide frequency range. Film capacitors also offer high surge and RF protection, and a high-dielectric withstanding voltage.

In addition, film capacitors can handle higher voltage than other types of capacitors. They are also more reliable and have a longer life span than other capacitors. They also cost less than other capacitors, making them ideal for most applications.