Film capacitor

A capacitor that uses a thin plastic film as its dielectric, with conductive electrodes deposited on or placed beside the film. Its stable, low-loss dielectric makes it useful in filtering, timing, and power electronics.

Metallized film capacitor: A film capacitor whose thin metal electrodes are deposited directly onto the dielectric film. Its self-healing action follows from the very thin deposited electrodes.
Dielectric: An electrically insulating material that polarizes in an applied electric field and stores electrostatic energy. The plastic film is the capacitor's dielectric layer.
DC-link capacitor: A capacitor connected across a direct-current bus to stabilize voltage and supply transient current. Film parts often smooth high-current DC buses in converters and drives.
Ceramic capacitor: A capacitor that uses a ceramic material as its dielectric. Ceramics are often smaller at high capacitance, but some types vary more with voltage.
Film-and-foil capacitor: A film capacitor built with separate metal foils alternating with dielectric film layers. Its robust foil electrodes trade compactness for high current capability.
Polypropylene: A thermoplastic polymer used as a low-loss, electrically insulating material. Its low dielectric loss suits precision and pulse film capacitors.
Snubber: A circuit that limits voltage or current transients in switching devices. Film capacitors absorb switching energy in many snubber circuits.
Aluminum electrolytic capacitor: A polarized capacitor that uses an oxide layer and liquid or solid electrolyte. Electrolytics offer much higher capacitance per volume but typically have shorter lifetimes.
Self-healing: The clearing of a small dielectric fault when local heating vaporizes nearby electrode material. Metallized designs can isolate a puncture instead of shorting permanently.
Polyester: A family of polymers that includes polyethylene terephthalate, used in insulating films and fibers. Polyester film permits compact capacitors with relatively high capacitance per volume.

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