Safety capacitors include two types: X capacitors and Y capacitors. X capacitors are capacitors that are connected across two power lines (L-N) and generally use metal film capacitors; Y-capacitors are capacitors that are respectively connected between two power lines and ground (L-E, N-E), usually appearing in pairs

 Firstly, we know that an electric capacity is composed of two metal electrodes sandwiched between insulating materials (dielectric). Due to differences in insulation materials, the types of capacitors formed also vary:
According to structure, it can be divided into fixed capacitors, variable capacitors, and fine tuned capacitors. According to the dielectric material, it can be divided into: gas dielectric capacitor, liquid dielectric capacitor, inorganic solid dielectric capacitor, organic solid dielectric capacitor, organic solid dielectric Electrolytic capacitor. According to polarity, it can be divided into polar capacitors and non-polar capacitors.
Capacitors have the function of isolating direct current through alternating current in circuits, and are therefore commonly used for inter stage coupling, filtering, decoupling, bypass, and signal tuning.
Precautions: Capacitors for suppressing electromagnetic interference from power sources
When using capacitors to eliminate noise in cross line power circuits, not only normal voltage but also abnormal pulse voltage (such as lightning) should be considered, which may cause the capacitor to smoke or catch fire. Therefore, the safety standards for cross line capacitors have strict regulations in different countries, so it is necessary to use certified capacitors.