Common mode chokes are often used to filter common mode electromagnetic interference signals in switching power supplies of computers. In the design of the board, the common mode inductor also plays the role of EMI filtering, which is used to suppress the outward radiation emission of electromagnetic waves generated by the high-speed signal line. The common mode inductor is essentially a bidirectional filter: on one hand, it is necessary to filter out the common mode electromagnetic interference on the signal line; on the other hand, it is necessary to suppress the electromagnetic interference from itself, so as to avoid affecting the normal work of other electronic equipment in the same electromagnetic environment.
