Common problem
Positive and negative effects of capacitors
Source：本站 | Time：2022-01-25 | Read：428
Capacitors are divided into polarized capacitors and non-polarized capacitors. Generally, porcelain chip capacitors, monolithic capacitors and polyester capacitors are non-polarized capacitors, and non-polarized capacitors do not need to consider polarity when using, and the pins of capacitors can be connected at will. Then, when using polarized capacitors, the positive and negative pins must not be connected wrongly, otherwise the leakage current of the capacitor will increase and even explode.
For electrolytic capacitors, the polarity can be judged by the pin (long positive and short negative) or by the logo of electrolytic capacitors, which has a small rectangle from top to bottom with a negative symbol inside, and the pin corresponding to this logo is the negative pole. What if the polarity of the capacitor is reversed?
In the first case, if the capacitor capacity is small and the voltage resistance is high, and the working voltage is low, the reverse connection of electrolytic capacitor is not visible.
In the second case, if the electrolytic capacitor has a large capacity and the voltage resistance value is similar to the working voltage, the electrolytic capacitor will not work for more than a few minutes before it is damaged. It is the general situation of the failure phenomenon, first bulging, then blowing, and finally burst. It still seems to be more dangerous. There are polarized capacitors can only DC power supply can not use AC. Because the special material inside the polarized capacitor is not able to withstand the reverse voltage, at this time the polarized capacitor to AC power may reverse breakdown or capacitor explosion.
Mainly because there is no polarity in AC power, so when AC power provides reverse voltage, the polarized capacitor is equivalent to reverse connection, then it is likely to burst or explode. Reverse polarity capacitor may be short-circuited. The internal structure of polarized capacitor is divided into positive, dielectric layer and negative. Because the dielectric layer of polarized capacitor has one-way conductive property, if the polarity is reversed, then the dielectric layer will lose the one-way conductive property and cannot play the role of insulation, so the polarized capacitor will be short-circuited naturally.
If the polarity of polarized capacitor is reversed, the resistivity will become smaller. First of all, let's have a preliminary understanding of the principle of electrolytic capacitor. If the electrolytic capacitor works normally, its positive electrode will form oxide film as electrolyte, if it is reversed, then its positive electrode is connected to the negative electrode of power supply, then it will not form oxide film as electrolyte, but electrolyze H2, at this time, the negative electrode of electrolytic capacitor will not form oxide film as electrolyte because of the special material.
Therefore, its resistivity will become smaller. As mentioned before, the failure phenomenon of polarized capacitor is that it bulges first, because the positive electrode does not form oxide film, but electrolysis H2, so the top of polarized capacitor bulges first under gas pressure, and then it keeps blowing gas (H2), and finally it will explode.
For electrolytic capacitors, the polarity can be judged by the pin (long positive and short negative) or by the logo of electrolytic capacitors, which has a small rectangle from top to bottom with a negative symbol inside, and the pin corresponding to this logo is the negative pole. What if the polarity of the capacitor is reversed?
In the first case, if the capacitor capacity is small and the voltage resistance is high, and the working voltage is low, the reverse connection of electrolytic capacitor is not visible.
In the second case, if the electrolytic capacitor has a large capacity and the voltage resistance value is similar to the working voltage, the electrolytic capacitor will not work for more than a few minutes before it is damaged. It is the general situation of the failure phenomenon, first bulging, then blowing, and finally burst. It still seems to be more dangerous. There are polarized capacitors can only DC power supply can not use AC. Because the special material inside the polarized capacitor is not able to withstand the reverse voltage, at this time the polarized capacitor to AC power may reverse breakdown or capacitor explosion.
Mainly because there is no polarity in AC power, so when AC power provides reverse voltage, the polarized capacitor is equivalent to reverse connection, then it is likely to burst or explode. Reverse polarity capacitor may be short-circuited. The internal structure of polarized capacitor is divided into positive, dielectric layer and negative. Because the dielectric layer of polarized capacitor has one-way conductive property, if the polarity is reversed, then the dielectric layer will lose the one-way conductive property and cannot play the role of insulation, so the polarized capacitor will be short-circuited naturally.
If the polarity of polarized capacitor is reversed, the resistivity will become smaller. First of all, let's have a preliminary understanding of the principle of electrolytic capacitor. If the electrolytic capacitor works normally, its positive electrode will form oxide film as electrolyte, if it is reversed, then its positive electrode is connected to the negative electrode of power supply, then it will not form oxide film as electrolyte, but electrolyze H2, at this time, the negative electrode of electrolytic capacitor will not form oxide film as electrolyte because of the special material.
Therefore, its resistivity will become smaller. As mentioned before, the failure phenomenon of polarized capacitor is that it bulges first, because the positive electrode does not form oxide film, but electrolysis H2, so the top of polarized capacitor bulges first under gas pressure, and then it keeps blowing gas (H2), and finally it will explode.
