1. The capacitor before AC rectification should use X capacitor;
2. X capacitors must meet the voltage requirements used. If they exceed the nominal voltage, they must be used in series with exactly the same capacitors (pay attention to voltage equalization);
3. The X capacitor must meet the temperature requirements, that is, under the highest specified working environment of the whole machine, the X capacitor body must meet the operating temperature of its X capacitor, and must not exceed the normal temperature range;
4. It is necessary to consider the possible pulse voltage at the input of the circuit. Different capacitors have different pulse voltages, and the withstand voltage of the capacitor cannot be less than the peak value of the pulse voltage in the circuit;
5. When the X capacitor is used on the input terminal, it is necessary to prevent the power cord plug from being charged for a long time due to the charging and discharging process of the capacitor when the power cord is unplugged. Therefore, in accordance with the relevant safety certification standards, the plug must be plugged and unplugged within the specified time The internal is reduced to the specified voltage; at this time, the X capacitor needs to be discharged in parallel with the bleeder resistor.
6. Due to the manufacturing process of X capacitors, large audio noise is often generated. At this time, it is necessary to select noise reduction capacitors in conjunction with product design.
7. According to the certification standard of the whole machine, select the X capacitor that meets the certification standard of the whole machine.
Common safety signs