LED display technicians have to know the capacitance knowledge

A capacitor is a container that can store electrical charge. It consists of two pieces of metal that are closer together, separated by an insulating material. A wide variety of capacitors can be made depending on the insulating material. Such as: mica, porcelain, paper, electrolytic capacitors, etc. In terms of construction, it is further divided into a fixed capacitor and a variable capacitor. The capacitor has infinite DC resistance, that is, the capacitor has a DC blocking effect. The resistance of the capacitor to the alternating current is affected by the alternating current frequency, that is, the capacitor of the same capacity exhibits different capacitive reactance to the alternating current of different frequencies. What will happen to this? This is because the capacitor operates on its charge and discharge function, and the power switch s is not closed. The two metal plates of the capacitor and other common metal plates are uncharged. When the switch S is closed, the free electrons on the positive plate of the capacitor are attracted by the power source and pushed onto the negative plate. Since the capacitor plates are separated by an insulating material, free electrons running from the positive plate are deposited on the negative plate. The positive electrode plate is positively charged due to the reduction of electrons, and the negative electrode plate is negatively charged due to the gradual increase of electrons.

There is a potential difference between the two plates of the capacitor. When this potential difference is equal to the supply voltage, the charging of the capacitor is stopped. At this time, if the power is turned off, the capacitor can still maintain the charging voltage. For a charged capacitor, if we connect the two plates with wires, due to the potential difference between the plates, the electrons will pass through the wires and return to the positive plate until the potential difference between the plates is zero. The capacitor is restored to an uncharged neutral state and there is no current in the conductor. The frequency of the alternating current applied to the two plates of the capacitor is high, and the number of times of charging and discharging of the capacitor is increased; the charging and discharging current is also enhanced; that is, the blocking effect of the capacitor on the alternating current with high frequency is reduced, that is, the capacitive reactance is small, and vice versa. Capacitors have a large capacitive reactance to low frequency AC power. For alternating current at the same frequency. The larger the capacity of the capacitor, the smaller the capacitive reactance, and the smaller the capacity, the larger the capacitive reactance.