What is Power Film Capacitor – Features, Working, Types & Applications


Power film capacitors are essential components in the world of electronics and electrical engineering. These capacitors are highly regarded for their ability to store and release electrical energy efficiently, making them indispensable in a wide range of applications. In this article, we will discuss the power film capacitors, exploring their definitions, key features, construction, working principles, types, and it’s applications.

Definition of Power Film Capacitor:

A power film capacitor, also known as a power film or metallized film capacitor, is an electronic component designed to store and release electrical energy. It consists of two conductive metal layers separated by a dielectric film, which can be made from materials like polypropylene or polyester. The dielectric film ensures that electrical energy can be stored without significant energy loss.

Features of Power Film Capacitor:

High Voltage Rating: Power film capacitors are capable of handling high voltage levels, making them suitable for applications where voltage fluctuations are common.

Low ESR (Equivalent Series Resistance): These capacitors offer low ESR, ensuring minimal power loss and efficient energy storage and discharge.

High Reliability: Power capacitors are known for their robust construction, ensuring long-term reliability even in harsh environments.

Self-Healing Property: If a power film capacitor experiences a minor breakdown, it can self-heal, restoring its functionality and preventing catastrophic failures.

Compact Design: These capacitors are available in compact sizes, making them suitable for space-constrained applications.

Construction of Power Film Capacitor:

These capacitors are consists of a wound or stacked design, where the metalized film is interleaved with an insulating dielectric material. The winding or stacking process allows for a higher capacitance value while maintaining a small form factor. The entire assembly is encapsulated in a protective casing to shield it from external influences.

Working of Power Film Capacitor:

It works on the principle of storing electrical energy in the form of an electrostatic field. When voltage is applied across the capacitor terminals, the dielectric material prevents the flow of direct current (DC) while allowing alternating current (AC) to pass through. This property allows them to store and release energy as needed in various electronic circuits.

Types of Power Film Capacitor:

There are main three types of power capacitors which are:

  • Wound film capacitors
  • Stacked film capacitors
  • Hybrid film capacitors


Power Inverters: Used in renewable energy systems and electric vehicles to store and regulate electrical power.

Motor Drives: Employed in motor control systems to enhance efficiency and reduce power losses.

Power Supplies: Utilized in power supply units to stabilize voltage and reduce electromagnetic interference.

DC-Link Capacitors: Enhance the performance of high-power converters and inverters in industrial applications.

Pulse Power Applications: Suitable for pulse power systems in medical devices, radar systems, and particle accelerators.

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