The material of capacitor

May 6,2016
Plastic Film (Film Capacitor) is also called Plastic Film Capacitor (Plastic Film Capacitor).The plastic film as the dielectric.
Brief introduction:
Capacitor in the medium is different, it's a lot of more phyletic, for example: electrolyte capacitor, paper, film capacitors, ceramic capacitors, mica capacitor, air condenser, etc.But the most frequently used in the audio equipments, when the electrolytic capacitor and Film capacitor (Film).Electrolytic capacitor is used mostly in large capacitance are needed, such as the main power supply part of the filter capacitor, in addition to filtering, and concurrently do store electricity.Film capacitors are widely used in analog signal coupling, bypass (the commissure) power supply noise, etc.
The structure and classification:
Film capacitor is with metal foil as the electrode, and poly (ethyl ester, polypropylene, poly (ethylene or stupid polycarbonate plastic films, such as from both ends after overlapping, capacitor winding into the structure of the cylinder.And depending on the species of plastic film respectively called ethyl poly capacitance (also called tool capacitor), polypropylene capacitor (PP), polystyrene capacitor (PS) and poly (carbonate capacitance.

The typical schematic diagram of film capacitors
Film capacitor because of has many excellent properties, so it is a kind of excellent performance of capacitors.Its main sex, such as the following: no polarity, high insulation resistance, excellent frequency characteristic (broad frequency response), and the dielectric loss is very small.Based on the above advantages, so the film capacitor is widely used in analog circuit.Especially in the part of signal coupling, must use good frequency characteristic and low dielectric loss of capacitor, to ensure that the signal transmission, does not have the too big distortion occurs.Its structure is the same as the paper media is polyester or polystyrene, etc.Polyester film capacitor, high dielectric constant, small size, large capacity, better stability, suitable for the bypass capacitor.Polystyrene film capacitor, small dielectric loss, high insulation resistance, but the temperature coefficient is big, can be used in high frequency circuit.Among all of the plastic film capacitors, polypropylene (PP) and polystyrene (PS) characteristics of the capacitance is most significantly, of course the price of this two kinds of capacitor.In recent years, however, audio equipment in order to promote the quality of the sound, the parts material has been used by more and more advanced, the price is not the most important factor, so in recent years the PP capacitance and PS capacitor is used in audio equipment of the frequency and quantity is higher and higher also.Readers can often see so-and-so brand equipment, which use how many so-and-so brand PP mass or PS capacitance, for endorsement on sound quality, its truth in that.Characteristics: thin film capacitor capacity in the range of 3-0.1 uF, pf the dc working voltage is 63-500 - v, suitable for high frequency, low frequency, the leakage resistance is greater than 10000 Ω.