The principle of capacitor charging and discharging
Time：2021.09.16
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The basic function of a capacitor is charging and discharging. The many circuit phenomena extended by this basic charging and discharging effect make the capacitor have a variety of different uses. For example, in an electric motor, we use it to produce a phase shift. In a photo flash , Use it to generate high-energy instantaneous discharge, etc., and in electronic circuits, capacitors are used for different properties. Although there are many different uses, they are all from charging and discharging. For example, the bypass capacitor can actually be called a smoothing capacitor.
The following is the classification of the general customary names to illustrate the role and basic requirements of capacitors in different circuits.
1. DC charging and discharging capacitors
The basic function of a capacitor is both charging and discharging, so the direct use of this charging and discharging function is one of the main uses of the capacitor. The capacitor in this application will absorb and store when the supply energy is higher than the demand, and when the supply energy is lower than the demand or there is no energy supply, the stored energy can be released.
In the rectifier circuit, the diode only conducts the current in the second half of the cycle, and stores electrical energy on the capacitor during the conduction period. During the negative half of the cycle, the diode does not conduct electricity. At this time, the electrical energy required by the load depends on the supply of the capacitor.
2. Power smoothing filter and anti-cross-connect capacitor
The charging and discharging capacitors in the aforementioned power rectifier circuit are divided into charging and discharging time, so ripples are bound to exist. In order to reduce the ripple rate as much as possible, an additional capacitor can be added. This capacitor is purely a smooth ripple. For use.
