Both X and Y capacitors are gauge capacitors. The difference is that X capacitor is connected at both ends of the input line to eliminate differential mode interference, while Y capacitor is connected between the input line and ground line to eliminate common mode interference.

X capacitor adopts shaped square high voltage CBB capacitor. CBB capacitor not only has better electrical performance, but also can effectively reduce the influence of high frequency pulse on switching power supply in parallel with the input end of power supply.

Y capacitors -- with high voltage tiles. The Y-type capacitor is connected between the phase line and the ground line. In order not to exceed the permissible leakage value of the ground wire defined by the relevant safety standards, the values of these capacitors are approximately several nF. In general, the Y capacitor should be connected to a wire with high noise interference;

Y capacitor is divided into Y1 capacitor and Y2 capacitor, Y1 belongs to the double insulation Y capacitor, used for connecting the first and second sides; Y2 belongs to the basic single insulation Y capacitor, which is used to connect the primary side pair protection earth, i.e. FG line.

Safety capacitor is used for such occasions, that is, capacitor failure will not lead to electric shock, does not endanger personal safety.

(IEC664) X1 >2.5kV ≤4.0kV SW {{

X2 2.5 kV IY - F 6 BXV or less

The X3 1.2 kV or less} _. T.S @; 9e

Y Safety gauge Capacitor safety level Insulation type Rated voltage range

Y1 Double insulation or reinforced insulation ≥ 250V

Y2 basic insulation or additional insulation ≥150V ≤250V

Y3 basic insulation or additional insulation ≥150V ≤250V

Y4 Basic insulation or additional insulation <150V

X capacitance inhibits differential mode interference

Y capacitors suppress common mode interference

According to IEC 60384-14, capacitors are divided into X capacitors and Y capacitors,

1. X capacitor refers to the capacitor spanning between L and N.

2. Y capacitor refers to the capacitor spanning between L-G/N-G. (L = Line, N = Neutral, G = Ground).

(1) The most important purpose of adding Y-Cap is to pass EMI

(2) Now most people do not want to add Y-Cap, there are two points:

A. In order to reduce the cost, one Y-cap costs 0.3RMB. Now everyone is designing NO Y

B. Our switching power supply has a lot of trouble when used in some audio equipment, such as MP3 switching power supply does not use linear power supply, fixed station telephone, ADSL switching power supply will have noise;

3. Safety regulations do not say that y-CAP must be added, as long as your EMI can pass, Y-CAP will affect the leakage current