Film capacitors in various applications - A note

The following are the advantages of film capacitors that make them suitable for various applications:

• No polarity
• Reliable
• Stability
• Available from pF to uF
• High surge current capability
• Low inductance
• Low cost
• Low ESR
• High precision capacitor value
• Can withstand high power 
• Value retention for longer time, long life
• High voltage withstanding capability
• High frequency handling capability
• Customization

What is a film capacitor?

A film capacitor uses a thin layer of plastic as dielectric. Later, this is treated to come up with various film capacitor types like metallic film capacitor, polyester film capacitor, PTFE film capacitor, etc.

Various applications:

There are several advantages of metal film capacitors that make them useful in various applications. Have you seen the latest LED bulb applications? The most preferred capacitor is metal film type. These are relatively stable and cheaper which makes them suitable for low margin and stability desired LED market.

We can see PTFE film capacitors (polytetraflouroethylene) used in aerospace and military applications. PTFE film capacitors are heat resistant, so, this is preferred.

Snubber circuits use polypropylene film capacitors. This is because of their higher current carrying capability and low inductance.

Other applications:

• Filters
• Lighting ballasts
• decoupling capacitors
• RFI suppression

What are the disadvantages of film capacitors?

• Bulky compared to other capacitors
• Difficult to find SMT parts for these capacitors for all values
• Little costly