Posted on 13 June 2020

Film Capacitors








Capacitors for industrial use are found in nearly all electronic applications. They are used in fans, pumps, conveyors, elevators, fork lifts, windmills, solar converters, UPS, welding, X-ray and so on. The reason for this is the variety of technical functions of film capacitors such as filtering, EMI suppression, smoothing, energy storage, snubbering (snubbing), and resonance.

In film capacitors, an ultra-thin vacuum evaporated metallization layer is used as an electrode. Metallization profiles allow different advantages (i.e. serial connections). A low temperature during the metallization process and a high quality of welding equipment characterize the process technology.  

Important characteristics of film capacitors include contact stability, reliability, and high current capability. In the case of dielectric breakdown, film capacitors have the ability to withstand over-voltages. When high current is generated, the ultra-thin metallization layer vaporizes. The affected area will be electrically insulated from the rest of the capacitor and the capacitor can continue operating at normal rated conditions. Compared with other cap technologies, this special process technology will not loose capacitance or, in the worst case, blow up in the same over-voltage conditions.

The main (general) advantages of film capacitors over aluminum electrolytic capacitors are:

  •  Life time of 200k hours
  •  Self-healing higher peak over-voltage
  •  Stable capacitance and electrical parameters with time and temperature
  •  Much higher absolute peak current
  •  Much higher thermal dissipation capability
  •  Higher ripple current - Usage in modular systems  


For more information, please read:

Introduction to Capacitors

Aluminium Electrolytic Capacitors - Overview and Key Applications

EMC Filter as an Application for Film Capacitors

Film Capacitors for DC-Link


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