Views: 1 Author: Site Editor Publish Time: 2018-04-16 Origin: Site
A capacitor is a container in which charges are stored. It is made up of two pieces of metal close to each other, separated by insulating material. A variety of capacitors can be made according to the insulating material. Such as: Mica, porcelain dielectric, paper dielectric, electrolytic capacitors and so on. In structure, it is divided into fixed capacitor and variable capacitor. The capacitor has an infinite force on the DC resistance, that is, the capacitor has the function of isolating the DC. The resistance of capacitors to AC is affected by AC frequency, that is, capacitors of the same capacity present different capacitive reactance to AC at different frequencies. Why would this happen? This is because the capacitor depends on its charge-discharge function, when the power switch s is not closed. Two plates of metal and other ordinary metal plates of capacitors are not charged. When the switch S is closed, the free electrons on the positive plate of the capacitor are attracted by the power supply and pushed onto the negative plate. Because there is insulation between the two plates of the capacitor, the free electrons that run from the positive plate accumulate on the negative plate. The positive plate is positively charged by the reduction of electrons, and the negative plate is negatively charged by the gradual increase in the number of electrons.
There is a potential difference between the two plates of the capacitor. When the potential difference is equal to the voltage of the power supply, the charge of the capacitor stops. If the power supply is cut off, the capacitor can still maintain the charging voltage. For a rechargeable capacitor, if we connect the two plates with a wire, because of the potential difference between the two plates, the electron will pass through the wire and return to the positive plate until the potential difference between the two poles is zero. The capacitor returns to a neutral state without charge, and there is no current in the conductor. On the contrary, capacitors produce large capacitive reactance to low frequency alternating current. For alternating current at the same frequency. The larger the capacity of the capacitor, the smaller the capacitance, the smaller the capacity, the greater the capacitance.