High Power Inverter/Filter Inductor When the normal current in the circuit flows through the common mode inductor, the current in the inductor coil wound in the same phase to produce the reverse magnetic field and cancel each other out, the normal signal current is mainly affected by the coil resistance (and a small amount of damping caused by leakage inductance); when there is a common mode current flowing through the coil, due to the common mode current isotropy, will produce the same magnetic field in the coil and increase the inductance of the coil, so that the coil shows a high impedance, producing a strong damping effect. When there is a common-mode current flowing through the coil, it will increase the inductance of the coil by increasing the magnetic field in the same direction due to the isotropy of the common-mode current. It is commonly used to filter common mode EMI signals in switching power supplies of computers. In board design, common mode inductors also play a ro…