Analysis of the use and characteristics of polyester capacitors(II)

Theoretically (ie, assuming that the capacitor is a pure capacitor), the larger the capacitor, the smaller the impedance and the higher the frequency of the pass. However, in practice, capacitances in excess of 1 μF are mostly electrolytic capacitors and have a large inductance component. Therefore, the impedance increases when the frequency is high. Sometimes there is a large capacity electrolytic capacitor connected in parallel with a small capacitor. At this time, large capacitors filter low frequencies, and small capacitors filter high frequencies. The role of the capacitor is to pass AC DC blocking and pass high-frequency blocking.

The higher the capacitance, the easier it is for high frequencies to pass. Specifically used in filtering, large capacitors (1000μF) filter low frequency, small capacitors (20pF) filter high frequency. There have been users of the filter capacitor like a "bunker." Since the voltage at both ends of the capacitor will not mutate, it can be seen that the higher the signal frequency, the greater the attenuation. It can be said that the capacitor is like a pond, and the amount of water will not change due to the addition or evaporation of a few drops of water. It converts the change in voltage into a change in current. The higher the frequency, the greater the peak current, thus buffering the voltage. Filtering is the process of charging and discharging.