Polystyrene capacitors belong to the category of organic film capacitors, and their dielectric is polystyrene film, and there are two types of electrodes: metal foil type and metal film type. Since the polystyrene film is a heat-shrinkable oriented film, the wound capacitor can be made into a non-sealed structure by the method of self-heat shrinkage polymerization. For high-precision, sealed capacitors, metal or plastic shells are used for potting and packaging. Capacitors made with metal film electrodes are called metallized polystyrene film capacitors.
Polystyrene film capacitors have the following characteristics:
①The capacitance range of the capacitor is wide. Generally, it is 10pF-2μF.
②The dielectric absorption is very poor, the insulation resistance is high, and the capacitance stability is good.
③Metalized polystyrene capacitors have good self-healing ability, but when used in high-frequency circuits, the loss tangent value will increase, and the insulation resistance will be greatly reduced.
④The temperature coefficient is small, but the heat resistance is poor.
⑤ It can be made into precision capacitors, and the allowable deviation can reach ± 0.1%.
⑥It can be made into high-voltage capacitors, and the maximum working voltage can reach 40kV.
⑦The production process is simple and the cost is low.
Polystyrene film capacitors are suitable for working under the conditions of ambient temperature of -40℃~+55℃, and can be used in high-frequency circuits, but metalized polystyrene capacitors are not suitable for high-frequency and high-insulation resistance occasions.