The polar capacitor and the non-polar capacitor are identical in principle, both storing the charge and releasing the charge; the voltage on the plate (here the electric potential accumulated by the charge is called the voltage) cannot be abruptly changed.
The difference is that the medium is different, the performance is different, the capacity is different, the structure is different, and the use environment and use are also different. Conversely, according to the needs of production practice, people have experimentally manufactured capacitors with various functions to meet the normal operation of various electrical appliances and the operation of new equipment. With the development of science and technology and the discovery of new materials, higher quality and diversified capacitors will continue to emerge.
Different media
What is the medium? To put it bluntly is the substance between the two plates of the capacitor. Most of the polar capacitors use electrolyte as the dielectric material, and usually the same volume of capacitor has a large capacitance capacity. In addition, different electrolyte materials and processes produce polar capacitors with the same volume capacity. There is also a close relationship between pressure resistance and the use of dielectric materials. There are also many non-polar capacitor dielectric materials, mostly using metal oxide film, polyester and so on. Due to the reversible or irreversible performance of the medium, the environment with extreme and non-polar capacitance is determined.
Different performance Performance is the requirement for use, and maximizing demand is the requirement for use. If the power supply part of the TV is filtered with a metal oxide film capacitor, and the capacitor capacity and withstand voltage required for filtering are to be achieved. I am afraid that I can only install a power supply inside the case. Therefore, as a filter, only polar capacitors can be used, and polar capacitors are irreversible. That is to say, the positive pole must be connected to the high potential end, and the negative pole must be connected to the low potential end. Generally, the Electrolytic capacitor is above 1 microfarad, and it is used for coupling, decoupling, and power supply filtering. Non-polar capacitors are mostly below 1 microfarad, participating in resonance, coupling, frequency selection, current limiting, and so on. Of course, there are also large capacity and high withstand voltage, which are used in the reactive power compensation of electric power, the phase shifting of the motor, and the variable frequency power supply. There are many types of non-polar capacitors, not to mention them one by one.
Different capacity As mentioned above, capacitors of the same volume have different capacities and are not described one by one.
Different structure
In principle, it is possible to use a capacitor of any shape in the environment in which the tip discharge is not considered. Commonly used electrolytic capacitors (having a polar capacitor) are circular, and the square shape is rarely used. The shape of the non-polar capacitor is very varied. Like tube type, deformed rectangle, sheet type, square type, round type, combined square type and round type, etc., it is used where it is used. Of course, there is invisible, here the invisible refers to the distributed capacitance. For distributed capacitors, high frequency and intermediate frequency devices must not be ignored.
Use environment and use In the repair of home appliances, all of the above can be encountered. If you want to understand the truth in a simple way, you must rely on your own imagination. Here is just a brick-and-mortar, please correct me.
Because of its internal material and structure, the capacity of polar capacitors (such as aluminum electrolysis) can be made very large, but its high frequency characteristics are not good, so it is suitable for power supply filtering and other occasions, but also has high frequency characteristics. Polar capacitor - 钽 electrolysis, it is relatively expensive;
The non-polar capacitor is small in size, low in price, and good in high frequency characteristics, but it is not suitable for large capacity. Like ceramic capacitors, monolithic capacitors, polyethylene (CBB) capacitors, etc., ceramic capacitors are generally used in high-frequency filtering and oscillating circuits.
The magnetic capacitor is a capacitor in which a ceramic material is used as a meson and a silver layer is burned on the surface as an electrode. Magnetic capacitors have stable performance. Loss and leakage are small, suitable for high frequency and high voltage circuits.
In general, the insulating material between the two poles of the capacitor has a large dielectric constant (such as ferroelectric ceramics, electrolyte) suitable for making large-capacity and small-volume capacitors, but the loss is also large. Low dielectric constant (such as ceramic), low loss, suitable for high frequency applications.
