The knowledge of the capacitance of these LED displays, will you?
Capacitors, often referred to simply as their ability to hold charge, are capacitors. It consists of two pieces of metal that are closer together, separated by an insulating material. According to different insulation materials, a wide variety of capacitors can be made. 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 deviation between the actual capacitance of the capacitor and the nominal capacitance is called the error, and the accuracy is called within the allowable deviation range. A variable capacitor is a capacitor whose capacitance can be adjusted within a certain range. When the relative effective area or the inter-chip distance between the pole pieces is changed, its capacitance changes accordingly. It is usually used as a tuning capacitor in a radio receiving circuit. The capacitor has infinite 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 the alternating current, that is, a capacitor of the same capacity exhibits a different capacitive reactance to an alternating current of a different frequency.
Why is there a capacitive resistance phenomenon? The original capacitor is operated by its charge and discharge function, and the power switch s is not closed. The two metal plates of the capacitor are uncharged like other general metal plates. 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 distance between the two plates of the capacitor is made of insulating material, the free electrons running from the positive plate are piled up on the negative plate. The positive electrode plate is positively charged due to electron reduction, and the negative electrode plate is negatively charged by the gradual addition 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 moment, 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, because of 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 recovers 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, the number of times of charging and discharging of the capacitor is increased, and the charging and discharging current is also enhanced. That is to say, the blocking effect of the capacitor on the high-frequency alternating current is reduced, that is, the capacitive reactance is small, whereas the capacitor has a large capacitive reactance to the low-frequency alternating current.
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