How to identify common inductors and differential inductors

Common mode inductors and differential mode inductors are widely used in industrial circuits. How can we quickly and accurately distinguish and produce them?

1.Common mode inductors and differential mode inductors are one of the components that are effective in resisting electromagnetic interference. They are widely used in various filters, switching power supplies and other products. However, common mode inductors are used to suppress common Mode interference, while differential mode inductors are used to suppress differential mode interference. Both are important filter inductors. 

2. Identification of toroidal inductors and differential mode inductors. Although both inductors are filter inductors, their different functions determine the appearance and winding methods. For common mode inductors, they are wound on the same core. , and the coil diameter and number of turns of the two windings are the same, but the winding directions are opposite. A set of coils has two pins, so the common mode inductor will have 4 pins; while the differential mode inductor is wound around a core There is only one coil, so it only has 2 pins, so common mode inductors and differential mode inductors can be distinguished from the number of pins.

3. Application of common mode inductors and differential mode inductors The following figure is a partial circuit diagram of an EMI filter circuit. L1 is a common mode inductor, which has a total of four pins 1-4, while L2 and L3 are differential mode inductors, which have From the two pins 1-2, it can be seen that the differential mode inductor passes through the AC power supply current. This differential mode inductor can withstand a large AC current and usually appears in pairs.