Views:2 Author:Site Editor Publish Time: 2020-10-30 Origin:Site
Film capacitors are electronic components, which are used in many household appliances and have a wide range of applications. Film capacitors are electronic components made of metal foil, polypropylene, polystyrene and other materials. With many advantages and superior performance, it is now the mainstream capacitor.
Classification of film capacitors:
Film capacitors are capacitors in which metal foil is used as an electrode, and plastic films such as polyethylene, polypropylene, polystyrene or polycarbonate are overlapped from both ends and then wound into a cylindrical structure. According to the type of plastic film, they are called polyethylene capacitors (also known as Mylar capacitors), polypropylene capacitors (also known as PP capacitors), polystyrene capacitors (also known as PS capacitors) and polycarbonate capacitors.
Classified by film, it can be divided into about 4 types, namely:
1. Polyester capacitor (also called Mylar capacitor)
2. Polypropylene capacitors (also called PP capacitors), CBB belongs to this category
3. Polystyrene capacitors (also known as PS capacitors)
4. Polycarbonate capacitor
These types of capacitors are roughly similar in structure, similar to paper capacitors. Most of them are made of materials such as polystyrene. These types of film capacitors have the characteristics of good stability, small size, large capacity, etc., and are often used as bypass capacitors in circuits.
The pp capacitor and ps capacitor have the best performance among many film capacitors. Of course, pp capacitor and ps capacitor are also the most expensive capacitors among all film capacitors. PP capacitors and ps capacitors are often used in audio equipment. Manufacturers often use two types of capacitors for publicity. This shows the status of pp paper capacitors and ps capacitors in audio equipment.
Film capacitor characteristics:
The film capacitor has many excellent characteristics, so it is an excellent capacitor. Its main equivalences are as follows: non-polarity, high insulation resistance, excellent frequency characteristics (wide frequency response), and low dielectric loss. Based on the above advantages, film capacitors are widely used in analog circuits. Especially in the signal cross-connection part, capacitors with good frequency characteristics and extremely low dielectric loss must be used to ensure that the signal will not be too distorted during transmission. Among all the plastic film capacitors, polypropylene (PP) capacitors and polystyrene (PS) capacitors have the most remarkable characteristics. Of course, the prices of these two types of capacitors are relatively high. However, in recent years, in order to improve the sound quality of audio equipment, the parts and materials used have become more and more advanced. Price is not the most important consideration. Therefore, in recent years, the frequency and quantity of PP capacitors and PS capacitors used in audio equipment have also increased. Higher.
Film capacitor structure:
Film capacitors generally refer specifically to film adjustable capacitors, which are made of multilayer aluminum sheets connected together with copper screws to make fixed sheets, and then insulated with thin films. The adjustable part is made of aluminum sheets connected together with adjustable handles as moving sheets. Then insert it into the mutually insulated stators, and use the screwing of the handle to select and change the capacitance. Generally, it is made into double, called polyester film double variable capacitor. There are many other capacitors, all of which can be equivalent to two mutually insulated metal plates with lead wires.
Film capacitor structure diagram:
Advantages of film capacitors:
High insulation resistance and good heat resistance. With self-healing and non-inductive properties. It has excellent high-frequency insulation performance. The capacitance and loss angle are independent of frequency in a large frequency range, and change little with temperature, while the dielectric strength increases with the increase of temperature, which is difficult for other dielectric materials . High temperature resistance and low absorption coefficient.