Radio interference suppression capacitors

Radio interference suppression capacitors are used in electronic circuits to reduce or prevent the interference in the high-frequency range. They are used to minimize electromagnetic interference (EMI) and ensure that an electronic device complies with the determined radio interference limits. RFI suppression capacitors are designed to pass high frequencies better than low frequencies, which allows them to absorb and minimize high-frequency interference. They are often installed in the combination with other filter elements such as inductors and ferrites in circuits to provide effective EMI suppression. There are two main types of RFI suppression capacitors:

Line voltage interference suppression capacitors (X capacitors): Their function is to suppress interference between the mains voltage and the neutral conductor. They are often used in power supply units and other electrical devices that are connected directly to the mains.

Interference suppression capacitors for DC voltage (Y capacitors): They are used to reduce interference between the DC voltage supply and earth, such as in switching power supplies and other DC circuits.