X capacitor and Y capacitor is a more common capacitor in the safety capacitor, in the AC power supply input, generally need to add three safety capacitors to suppress EMI conducted interference, they are used in the power supply filter, to play a power supply filtering role, respectively, common mode, differential mode work disturbance to play a filtering role. That the capacitor should be how to choose it? I’ll give you the following.
Generally X capacitor is connected in parallel between the fire line and zero line suppression, according to the actual needs, the capacitance of X capacitor is allowed to be larger than the capacitance of Y capacitor, but at this time must be connected in parallel with a safety resistor at both ends of X capacitor, because the capacitor charging and discharging process to the power cord plug charged for a long time, to prevent the power cord unplugged electrocution.
Therefore, the total capacity of Y capacitor is not more than 4700PF. The capacitor must be qualified with safety certification! Prevent causing electronic equipment leakage or case charged, easily endanger personal safety and life!
The peak pulse voltage overvoltage level allowed in the safety level of safety capacitor: X1>2. 5kV ≤4. 0kV, X2 ≤2. 5kV, X3 ≤1. 2kV, the safety level of safety capacitor insulation type rated voltage range Y1 ≥ 250V, 8KV withstand voltage; Y2 ≥150V ≤ 300V, 5KV withstand voltage.
The question I received from the customer is: It needs to withstand 2000V peak surge voltage. Now the use of 0. 1μF X capacitors and 2200pF Y capacitors, so these capacitors should be at least how much withstand voltage? DC withstand voltage 100V and 250V capacitors, these capacitors are able to withstand the surge shock?
Here, for example, is the 220V system then choose 275V safety capacitors, 380V system choose 440V or with two 275V series, surge because less than 2.5KV so choose X2 capacitors. Here to put forward a few points in particular.
①You can’t use ordinary capacitors instead of safety-regulated capacitors, you must have safety-regulated capacitors with safety certification, which is responsible for life!
②The safety-standard capacitors are generally marked with the word withstand voltage, but their real DC withstand voltage is much higher than the marked withstand voltage (the marked withstand voltage of 250V can be as high as 2KV), so don’t use ordinary capacitors with the same nominal withstand voltage as the safety-standard capacitors, and the capacitors must be certified!
2,7 V 3000F superkondensatorius

2,7 V 3000F superkondensatorius

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