Analysis of the Quality of Common Mode Inductor Materials 3

Baidu explains the principle of common mode inductance more clearly than I do: two coils are wound on the same iron core, with the same number of turns and phase (wound in the opposite direction). In this way, when the normal current in the circuit flows through the common mode inductor, the current generates a reverse magnetic field in the inductor coils wound in the same phase and cancels each other out. At this time, the normal signal current is mainly affected by the coil resistance (and a small amount of damping caused by leakage inductance); When a current with common mode interference flows through the coil, a magnetic field in the same direction is generated inside the coil, which increases the inductance of the coil and makes it exhibit high impedance, producing a strong damping effect to attenuate the common mode current and achieve the purpose of filtering.

Overall advantages:

The most important point is that it has low cost (the one I use is 0.9 RMB), can be wound by machine, is efficient, and commonly uses UU9.8 or UU10.5;  diode

With a skeleton, the winding process should be better controlled, allowing for higher inductance to be achieved;

Voltage resistance and reliability should be targeted towards common mode magnetic rings;

Good plugin, easy installation. With four legs, if the holes are in the right position, there shouldn't be any problem; Basically used in low current power supplies, because the wire diameter cannot be very thick, the current cannot be too large;

Overall disadvantage:

Space factor: The packaging location is large, perhaps because it is relatively strong and not as small and delicate as the magnetic ring;

The fever is quite severe, according to my actual measurement: under full load room temperature with 90V input, it can reach almost 90 degrees;diode

Application:

Generally used in situations with strict cost control or low power consumption.