Capacitive knowledge of LED display technology
A capacitor is a container that can store charge. It is composed of two metal pieces that are close together, separated by an insulating substance in between. According to different insulating materials, various capacitors can be made. Such as: mica, porcelain, paper, electrolytic capacitors, etc. In structure, it is divided into fixed capacitors and variable capacitors. The capacitor has infinite resistance to DC resistance, that is, the capacitor has a DC blocking effect. The resistance of a capacitor to alternating current is affected by the frequency of alternating current, that is, capacitors of the same capacity exhibit different capacitive reactances to alternating current of different frequencies. Why do these phenomena occur? This is because the capacitor works by its charge and discharge function, when the power switch s is not closed. The two metal plates of the capacitor are not charged like other ordinary metal plates. 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 insulating material between the two plates of the capacitor, free electrons running from the positive plate accumulate on the negative plate. The positive plate will be positively charged due to the decrease of electrons, and the negative plate will be negatively charged as the electrons gradually increase.
There is a potential difference between the two plates of the capacitor. When this potential difference is equal to the power supply voltage, the charging of the capacitor stops. If the power is cut off at this time, the capacitor can still maintain the charging voltage. For a charged capacitor, if we connect the two plates with a wire, due to the potential difference between the two plates, the electron will return to the positive plate through the wire until the potential difference between the two plates is zero. The capacitor returns to a neutral state without electricity, and there is no current in the wire. The frequency of the alternating current applied to the two plates of the capacitor is high, and the number of charge and discharge times of the capacitor is increased; the charge and discharge current is also enhanced; Capacitors have a large capacitive reactance to low-frequency alternating current. For alternating current of 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.
The performance of the capacitor directly affects the overall quality of the LED display. Therefore, the maintenance personnel need to master certain knowledge of capacitance in order to better apply the LED display.