Film Capacitors Brief Introduction:
The film capacitor is a non-polarized capacitor and its dielectric is made using thin plastic films. These plastic films are sometimes metallized and are available in the market under the name “metallized capacitor”. These capacitors are sometimes also called as a metallized capacitor or plastic capacitors. A Thin Film Capacitor is nothing but bipolar capacitors with plastic films as their dielectric. These films are either metallized or just placed in layers to form out a roll or a candy-like the rectangular shape. The dielectrics popularly used are Polypropylene(PP)/ Polyethylene terephthalate (PET)/Polytetrafluoroethylene(PTFE)/ Polyphenylene Sulfide(PPS)
The main advantage of using a film capacitor is that it has a very low distortion factor and exceptional frequency characteristics. The wide range of plastic film used for different film capacitors, making them versatile. Also, these capacitors do not wear off quickly and are apt for high voltageand high-frequency applications such as coupling/decoupling circuits, ADC, audio circuits and many more.
UF Capacitors film capacitors family:
1)Common series: CL21 metallized polyester film capacitors, CBB21 metallized polypropylene film capacitors
2) X2 MKP capacitors, safety type
3) Axial lead film capacitors, Premium audio capacitors
4) CBB81. MMKP82 high voltage film capacitors
What is the Construction of Film Capacitor?
The generic manufacturing method for these capacitors starts by withdrawing a thin layer of plastic film. The thickness of this film decides the capacitance value. Since the capacitance value increases with a decrease in the distance between the electrodes, therefore a lower thickness of the film indicates a higher capacitance value. In general, the typical capacitance value for these capacitors lies in between 1nF to 10uF.
Production Flow for Film Capacitors
Difference between film capacitors and Electrolytic Capacitor and Ceramic Capacitor:
The first difference which is quite evident between these three capacitors is the type of dielectric used and their construction. While the film capacitors use thin sheets of plastic films, ceramic capacitors have sheets made out of ceramic material as the dielectric. Both of them are bipolar in nature. The electrolytic capacitors, on the other hand, have oxides acting as dielectric and are polar in nature.
The differences in their manufacturing and dielectrics have a huge impact on their performances. As already discussed, the plastic film/metallized film capacitors are available in a wide range of capacitance values. The ceramic capacitors, on the other hand, are ideal only for circuits that have low capacitance requirements. For particular applications like analog signal processing and audio circuits, the film capacitors are preferred over ceramic capacitors due to the low distortion factor which they offer. Also at high capacitances, ceramic capacitors tend to have high nonlinearities which affect the performance of the circuits.
For applications such as coupling/decoupling circuits, capacitors with high capacitance and a low cost are preferred. Therefore, both electrolytic and Film capacitors are good options to choose from. Another major factor that is considered while designing such circuits is the ESR (Equivalent Series Resistance) and ESL (Equivalent Series Inductance) value of the capacitor. As already discussed, Film capacitors have better ESR and ESL value and very less distortion factor when compared to electrolytic capacitors and are therefore preferred over aluminium electrolytic capacitors.
Also, if we compare the aging time between these three capacitors, film capacitors tend to resist the wearing out stage for the longest time among them. This makes them a better choice for high voltage and high-frequency applications.
What are features and characteristics of metallized Film Capacitor?
Wide capacitance range, small size
Self-healing property, long life
Epoxy resin sealing
Dielectric used: Polypropylene(PP)/ Polyester (PET)
What are application of Metallized Polyester Film Capacitor and Metallized Polypropylene film capacitors?
Common applications: The metallic film capacitors are widely used in power electronic circuits including DC link circuits, pulse circuits, switching circuits, etc. The low power metallized film capacitor find their use in decoupling and filtering applications.
UF Capacitors are very professional film capacitors supplier and factory in China. UF Capacitors produce both metallized polyester film capacitors and metallized polypropylene film capacitors. Now film capacitors temperature increased comparing with 10 years ago. UF Capacitors use better film foil and better production process, now metallized polyester film capacitors can reach 125C, while metallized polypropylene film capacitors can reach 110C operating temperature. Wide selection on film capacitors, pls visit UF Capacitors website: www.ufcapacitors.com
Our experienced engineers are willing to support customers for new products design.