The full name of X capacitance is generally called: X2 (X1/X3/MKP) capacitor for suppressing electromagnetic interference of power supply. Generally, the main functions in the circuit are: power supply cross-circuit circuit, EMI filtering, spark elimination circuit, etc. to ensure that the finished electronic products meet EMC requirements.
X capacitance: Since the location of this capacitor connection is also critical, it needs to comply with relevant safety standards. X capacitor is one of the safety capacitors. According to actual needs, the capacitance of the X capacitor is allowed to be larger than that of the Y capacitor, but at this time, a safety resistor must be connected in parallel at both ends of the X capacitor to prevent the power cord from being plugged and unplugged due to the charging and discharging process of the capacitor The power cord plug has been live for a long time. Safety standards stipulate that when the power cord of the machine in operation is unplugged, the voltage (or ground potential) at both ends of the power cord plug must be less than 30% of the original rated working voltage within two seconds.
As one of the safety capacitors, X capacitors also require the certification of safety inspection agencies. X capacitors are generally marked with safety certification marks and withstand voltage AC250V or AC275V, but its true DC withstand voltage is as high as 2000V or more. When using it, do not use ordinary capacitors with nominal voltage AC250V or DC400V at will.
Generally, the X capacitor uses a polyester film capacitor with a relatively large ripple current. This type of capacitor has a large volume, but the current that allows instantaneous charge and discharge is also large, and its internal resistance is correspondingly small.