Views:0 Author:Site Editor Publish Time: 2018-04-28 Origin:Site
In the AC power input, it is generally necessary to add three safe capacitors to suppress the EMI conduction interference. Ac power input is divided into three terminals: fire line LPU, zero line NCU, ground line (G).
The capacitance connected between the fire line and the ground line and between the zero line and the ground line is generally referred to as Y capacitor. The Y capacitor is between Len and PE, which provides the fastest circuit channel for the high frequency signal and reduces the influence of the high frequency signal on the system. Limiting Y capacitor values based on leakage currents should not be too large, generally in the NF level, and are usually used for power intake or bridge rectifier output (primary) between secondary ground, rack, shield or earth, It is also used to suppress common-mode interference between the input line rectifier output and the secondary output positive capacitor.
The capacitor in parallel between the fire line and the zero line suppression is commonly called X capacitor. The X capacitor is connected between Lon N and reduces some interference from the differential mode, which is mainly concentrated in the frequency below 1m. It is generally used in filters to suppress differential mode interference (DMI). Generally, the metal thin film capacitor X capacitor is the UF stage X capacitor to suppress the differential mode interference (DMI). The capacity of X capacitor is larger than that of Y capacitor.
Note that the larger the capacitance is, the greater the value is, and the leakage current between the earth and the earth will become larger, which will not meet the requirements of the safety regulations, and there will be a potential safety hazard. For example, some electrical appliances, sometimes used hemp hand, is this reason.