LED display capacitance knowledge analysis

Time:2018-11-28 Views:135

A capacitor is a container in which charge can be stored.It is made up of two pieces of metal that are close together and separated by an insulating material.Different kinds of capacitors can be made from different insulating materials.Such as: mica, porcelain, paper, electrolytic capacitor and so on.In structure, it is divided into fixed capacitor and variable capacitor.Capacitors have infinite resistance to direct current, that is, they have dc insulation.The resistance of capacitors to alternating current is affected by the frequency of alternating current.Why does this happen?This is because the capacitor depends on its charge-discharge function to work, when the power switch s is not closed.The two metal plates of the capacitor and other common metal plates are equally uncharged.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.Since there is insulation between the capacitor plates, free electrons from the positive plate pile up on the negative plate.The positive plate becomes positively charged as electrons decrease, and the negative plate becomes negatively charged as electrons increase.

There is a potential difference between the capacitor‘s two plates, and when this potential difference is equal to the power supply voltage, the capacitor‘s charging stops.If the power supply is cut off, the capacitor can still maintain the charging voltage.For a charged capacitor, if we connect the two plates with a wire, because of the potential difference between the two plates, electrons will pass through the wire and return to the positive plate until the potential difference between the two plates is zero.The capacitor returns to neutral state without charge, and there is no current in the wire.The ac frequency added on the two plates of the capacitor is high, and the charge and discharge times of the capacitor increase.Charging and discharging current is also enhanced;In other words, capacitors have less resistance to high frequency alternating current (ac), i.e., low capacitance reactance, whereas capacitors have more resistance to low frequency alternating current (ac).For alternating current of the same frequency.The larger the capacity of the capacitor, the smaller the reactance.