Common problem
Overview of polarized and non-polarized capacitors
Source：本站 | Time：2021-12-22 | Read：449
Overview of polarized and non-polarized capacitors:
The ideal capacitor has no polarity. However, in practice, manufacturers use special materials and structures when manufacturing large capacity capacitors, which leads to some actual capacitors having polarity. The common polarized capacitors are aluminum electrolytic capacitors, tantalum electrolytic capacitors, etc. Electrolytic capacitors are generally of relatively large capacity. However, it is not realistic to have large capacity of non-polarity capacitors, because the size of large capacity non-polarity capacitors will be very large, which is not convenient for practical application. Therefore, in the actual circuit, the capacity of polarized capacitor is generally smaller, and because the voltage in such a circuit is only in one direction, so the polarized capacitor is the most suitable. When we use a polarized capacitor, we should avoid its disadvantages and use its advantages. We can understand that a polarized capacitor is actually a capacitor that can only be used in one voltage direction. A non-polarized capacitor, on the other hand, can be used in both voltage directions. Therefore, in terms of voltage direction alone, the non-polarized capacitor is better than the polarized capacitor. It is possible to replace polarized capacitors with non-polarized capacitors as long as the capacity, operating voltage, and volume can meet the requirements.
Identification of polarized capacitors:
Most of the low value capacitors less than 1μF have no polarity, but almost all capacitors with 1μF or larger capacitance have positive and negative polarity. So far, the most commonly used polarized capacitors are electrolytic capacitors, and tantalum capacitors are also polarized capacitors. The polarity of the capacitor mounted on the printed board is marked by the symbols "+" and "-" on the case near the lead, in fact, most of the new capacitors have only -" symbols. These marks are not necessary because the positive leads of polarized capacitors will always be longer. Even if the markings are worn or completely erased, the polarity can be recognized immediately. Connecting a capacitor with the wrong polarity can damage it in some cases. It is also worth pointing out that even small reverse voltages and currents can damage some polarized capacitors. Such polarized capacitors do not show any external signs of damage, but if they are then used correctly in a circuit they can show sub-standard performance. Tantalum capacitors and some high grade electrolytic capacitors have a higher damage rate under reverse voltage.
The difference between polarized and non-polarized capacitors
1、The principle is the same. (1) both store charge and release charge; (2) the voltage on the pole plate (here the electric potential of charge accumulation is called voltage) cannot be changed abruptly. (3) The difference lies in the difference in medium, the
Different performance, capacity, structure, resulting in different environments and uses. Conversely, people have experimented and manufactured various functions of capacitors to meet the normal operation of various electrical appliances and new equipment according to the needs of production practice. With the development of science and technology and the discovery of new materials, better quality and diversified capacitors will continue to emerge.
2、The medium is different. What is the medium? To put it bluntly, it is the substance between the two polar plates of a capacitor. Most of the polarized capacitors use electrolyte as dielectric material, usually the same volume of capacitors with polarized capacitors have high capacity. In addition, the capacity of the same volume of polarized capacitors made by different electrolyte materials and processes will be different. Then there is a close relationship between voltage resistance and dielectric material used. There are also many dielectric materials for non-polarized capacitors, mostly using metal oxide film, polyester, etc. Due to the reversible or irreversible performance of the dielectric, it determines the use environment of the polarized and non-polarized capacitors.
3、The performance is different. The performance is the requirement of use, and the demand maximization is the requirement of use. If the use of phase shifting, shift etc. in TV sets.
4、Different capacity. 5、Different structure. In principle, without considering the tip discharge, the capacitor can be of any shape required by the use environment. Usually, electrolytic capacitors (polarized capacitors) are round, and the square shape is rarely used. There are many different shapes of non-polarized capacitors. There are many different shapes, such as tube, rectangle, chip, square, round, combined square and round, etc., depending on where they are used. Of course, there are invisible ones, and here invisible refers to distribution capacitors. For distributed capacitance in high frequency and medium frequency devices must not be ignored.
6、Use environment and usage are different.
The ideal capacitor has no polarity. However, in practice, manufacturers use special materials and structures when manufacturing large capacity capacitors, which leads to some actual capacitors having polarity. The common polarized capacitors are aluminum electrolytic capacitors, tantalum electrolytic capacitors, etc. Electrolytic capacitors are generally of relatively large capacity. However, it is not realistic to have large capacity of non-polarity capacitors, because the size of large capacity non-polarity capacitors will be very large, which is not convenient for practical application. Therefore, in the actual circuit, the capacity of polarized capacitor is generally smaller, and because the voltage in such a circuit is only in one direction, so the polarized capacitor is the most suitable. When we use a polarized capacitor, we should avoid its disadvantages and use its advantages. We can understand that a polarized capacitor is actually a capacitor that can only be used in one voltage direction. A non-polarized capacitor, on the other hand, can be used in both voltage directions. Therefore, in terms of voltage direction alone, the non-polarized capacitor is better than the polarized capacitor. It is possible to replace polarized capacitors with non-polarized capacitors as long as the capacity, operating voltage, and volume can meet the requirements.
Identification of polarized capacitors:
Most of the low value capacitors less than 1μF have no polarity, but almost all capacitors with 1μF or larger capacitance have positive and negative polarity. So far, the most commonly used polarized capacitors are electrolytic capacitors, and tantalum capacitors are also polarized capacitors. The polarity of the capacitor mounted on the printed board is marked by the symbols "+" and "-" on the case near the lead, in fact, most of the new capacitors have only -" symbols. These marks are not necessary because the positive leads of polarized capacitors will always be longer. Even if the markings are worn or completely erased, the polarity can be recognized immediately. Connecting a capacitor with the wrong polarity can damage it in some cases. It is also worth pointing out that even small reverse voltages and currents can damage some polarized capacitors. Such polarized capacitors do not show any external signs of damage, but if they are then used correctly in a circuit they can show sub-standard performance. Tantalum capacitors and some high grade electrolytic capacitors have a higher damage rate under reverse voltage.
The difference between polarized and non-polarized capacitors
1、The principle is the same. (1) both store charge and release charge; (2) the voltage on the pole plate (here the electric potential of charge accumulation is called voltage) cannot be changed abruptly. (3) The difference lies in the difference in medium, the
Different performance, capacity, structure, resulting in different environments and uses. Conversely, people have experimented and manufactured various functions of capacitors to meet the normal operation of various electrical appliances and new equipment according to the needs of production practice. With the development of science and technology and the discovery of new materials, better quality and diversified capacitors will continue to emerge.
2、The medium is different. What is the medium? To put it bluntly, it is the substance between the two polar plates of a capacitor. Most of the polarized capacitors use electrolyte as dielectric material, usually the same volume of capacitors with polarized capacitors have high capacity. In addition, the capacity of the same volume of polarized capacitors made by different electrolyte materials and processes will be different. Then there is a close relationship between voltage resistance and dielectric material used. There are also many dielectric materials for non-polarized capacitors, mostly using metal oxide film, polyester, etc. Due to the reversible or irreversible performance of the dielectric, it determines the use environment of the polarized and non-polarized capacitors.
3、The performance is different. The performance is the requirement of use, and the demand maximization is the requirement of use. If the use of phase shifting, shift etc. in TV sets.
4、Different capacity. 5、Different structure. In principle, without considering the tip discharge, the capacitor can be of any shape required by the use environment. Usually, electrolytic capacitors (polarized capacitors) are round, and the square shape is rarely used. There are many different shapes of non-polarized capacitors. There are many different shapes, such as tube, rectangle, chip, square, round, combined square and round, etc., depending on where they are used. Of course, there are invisible ones, and here invisible refers to distribution capacitors. For distributed capacitance in high frequency and medium frequency devices must not be ignored.
6、Use environment and usage are different.
