The function of safety regulation capacitor in power supply

The safety capacitance as safety capacitor has been well known to us, including safety regulation X capacitor and safety regulation Y capacitor, which plays an important role in protecting users' safety. The X capacitance is a capacitance between the two lines (L-N) connected to the power line. Generally, the capacitance of a metal film is selected; the Y capacitance is a capacitor which is connected to the two lines of the power line and between the ground (L-E, N-E), and generally occurs in pairs. Based on the limitation of leakage current, the Y capacitor value can not be too large, the general X capacitance is uF, and the Y capacitor is nF. X capacitor suppresses differential mode interference and Y capacitor suppresses common mode interference.

What are the specific uses of safety regulation capacitors on various power supply circuit boards?

1. Filter use of safety gauge

Filtering is a very important part of the safety regulation capacitor. Almost all power circuits are used. Theoretically, the larger the capacitance, the smaller the impedance, and the higher the frequency of passing through. But in fact, more than 1uF capacitors are mostly electrolytic capacitors, and have a large inductance component, so the impedance will increase when the frequency is high. Sometimes there is a larger capacitance than the electrolytic capacitor in parallel with a small capacitor. At that time, the large capacitor goes through the low frequency, and the small capacitor goes through the high frequency. The function of capacitance is to pass through high resistance and low frequency. The higher the capacitance is, the easier it is to pass through the low frequency. The higher the capacitance is, the easier it is to pass the high frequency. Specifically used in filtering, large capacitance (1000uF) filter low frequency, small capacitance (20pF) filter high frequency.

Safety capacitance is used as a filter capacitor. It can be compared to a "pond". Because the voltage at both ends of the capacitor does not change, it can be seen that the higher the frequency of the signal, the greater the attenuation, and the more image the capacitance is like a pond, which will not cause the change of water due to the addition or evaporation of several drops of water. It transforms the change of voltage into the change of current. The higher the frequency, the greater the peak current, thus buffering the voltage. Filtering is the process of charging and discharging.

2. Safety gauge capacitance as a bypass

The bypass capacitor is an energy storage device that provides energy for local devices. It can make the output of the regulator even and reduce the load demand. Like a small rechargeable battery, the bypass capacitor can be charged and discharged to the device. To minimize impedance, bypass capacitors should be close to the power supply pins and ground pins of the load devices. This can prevent ground potential elevation and noise caused by excessive input value. The earth bomb is the voltage drop of the earth connection when it is burr through high current.