In the design and application of electronic circuits, safety capacitors play a vital role, especially in ensuring circuit safety. Safety capacitors are divided into many types according to their applications and characteristics, the most common of which are X2 safety capacitors and Y capacitors. Although both types of capacitors are used to improve the safety of circuits, they have obvious differences in terms of voltage resistance, application location, and function.
X2 safety capacitors are a type of X-type capacitors and are mainly used between the live line and neutral line (L-N) of the AC power supply. According to different withstand voltage levels, Class X capacitors are divided into three subclasses: X1, X2 and X3. Specifically, the voltage withstand capability of the X1 capacitor is between 2.5 kV and 4 kV, the voltage withstand capability of the X2 capacitor does not exceed 2.5 kV, and the voltage withstand capability of the X3 capacitor is less than 1.2 kV. Compared with the X2 capacitor, the Y capacitor is mainly used between the live wire and the ground wire (L-G/N-G) of the AC power supply, and its voltage resistance is usually higher than the X2 capacitor. Class Y capacitors are divided into four subcategories: Y1, Y2, Y3 and Y4 according to their different voltage resistance capabilities. The voltage resistance of Y1 capacitor is higher than 8 kV, Y2 is higher than 5 kV, Y4 is higher than 2.5 kV, and there is no specific standard for the voltage resistance of Y3 capacitor.
The fundamental difference between X2 safety capacitors and Y capacitors lies in their voltage resistance and installation location. X capacitors, especially the X2 type, are mainly used between the live and neutral wires, while Y capacitors are used between the live and ground wires. In the power supply filter, these two capacitors perform their own duties, filtering common mode and differential mode interference respectively. The main concern of X capacitor is the withstand voltage rating, because it is directly affected by voltage peaks and needs to avoid the risk of short circuit. The Y capacitor pays more attention to the insulation level because it is directly related to leakage safety. Excessive capacitance of the Y capacitor may cause harm to people and equipment after the power is turned off. Therefore, from a safety perspective, Y capacitors are generally considered to have a higher safety factor.
In summary, although X2 safety capacitors and Y capacitors are both designed to improve the safety of circuits, they have significant differences in voltage resistance, installation location, and functions. Understanding these differences is critical for electronic engineers when designing and maintaining circuits to ensure their safety and stability.