Film capacitors
The film capacitor [old: wound capacitor] owes its name to its construction. A dielectric wound or vapour-deposited between two metal foils ensures high capacitance. Low internal resistance (ESR), low inductance (ESL) as well as high current carrying capacity and self-healing capability characterise this type of capacitor.
Specifications
- 100pF - 180µF
- 16V - 3000VDC
Designs
- SMD
- Radial leaded / box
- Axial
- Axial round / oval
Applications
- Automotive electronics
- HF resonant circuits
- Crossovers
- Booster capacitor
- Plasma research, etc.
DC-Link capacitors
- High rms currents (RMS)
- Low self-inductance
- Low series resistance (ESR)
- High surge current carrying capability
- Use in low-inductance DC buffer circuits and DC filtering, smoothing
AC filter capacitors
- High rms currents (RMS)
- High capacitance values
- Fast assembly
- Safe pressure relief
- High reliability and long life
Snubber capacitors
- High effective currents (RMS)
- Use as protection for thyristors and gate turn-off (G.T.O.) thyristors
Datasheets
PDF 66.4 Kb Structure & properties of film capacitors
Film capacitors usually consist of two aluminium foil electrodes with plastic films as dielectric. To ensure the necessary safety and reliability of a capacitor, it is necessary to use a sufficient film thickness. Typical advantages that relatively large film capacitors have over smaller metallised capacitors are their higher insulation resistance, better capacitance stability and good current carrying capacity.
High voltage and good pulse handling capability are further features of these capacitors. They also feature low internal resistance (ESR), small inductance (ESL), high current carrying capacity and self-healing capability.
Metallised film capacitors - smaller design
Unlike film capacitors, which use aluminium foils as electrodes, the electrodes of metallised film capacitors consist of a thin metal layer (about 0.03 microns thick) deposited on the dielectric film in a vacuum. Metallised capacitors are connected by a metal spraying process and by welding the leads to the sprayed ends. The main advantages of metallised capacitors are small dimensions and also the self-healing properties already mentioned.
