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In the circuit, most of the EMC problems are common mode interference.
So common mode inductor is also one of the powerful components commonly used ! When the equipment signal is interfered, we need to use the common mode inductor to filter the interfered signal. Here in MingDa, we will briefly introduce the principle and the use of common mode inductors.

The common mode inductor is a common mode interference suppression device with ferrite core. It consists of two coils with the same size and the same number of turns symmetrically wound on the same ferrite ring core to form a four terminal device. It has the function of suppressing the large inductance for the common mode signal, and has little effect on the small leakage inductance for the differential mode signal.

The principle is that when the common mode current flows, the magnetic fluxes in the magnetic ring overlap each other, so that there is a considerable inductance, which suppresses the common mode current. When differential mode current flows through, the magnetic fluxes in the magnetic ring cancel each other, and there is almost no inductance, so the differential mode current can pass without attenuation.

In general, the larger the common mode impedance is, the better. Therefore, we need to look at the device data when selecting the common mode inductor, mainly according to the impedance frequency curve. In addition, the influence of the differential mode impedance on the signal shall be taken into consideration when selecting, and the differential mode impedance shall be mainly concerned, especially the high-speed port.

Huizhou Mingda mainly manufacture toroidal common inductor, SMD common inductor, UU9.8 inductor, UU10.5, UU16.5 inductor . Welcome to Inquiry !