How to Identify the Quality of Common Mode Inductors in Switching Power Supplies 2

3. DC resistance: A good common mode inductor should have a low DC resistance, and the size of the DC resistance is related to the material, structure, and process of the inductor component. The smaller the DC resistance, the lower the power loss and the higher the efficiency.

4. Mutual inductance characteristics: A good common mode inductor should have a high mutual inductance coefficient, and the higher the mutual inductance coefficient, the stronger the common mode suppression ability. The testing of mutual inductance coefficient can be carried out through LRC instruments.  diode

5. Temperature characteristics: A good common mode inductor should have good temperature characteristics, that is, its frequency and impedance characteristics change less at different temperatures.

3、 Common common mode inductor faults

1. Short circuit: A common mode inductor short circuit can cause the power line to disconnect, making the switching power supply unable to function properly. Short circuits are usually caused by damage to the insulation layer of inductive components or short circuits between coils.

2. Open circuit: An open circuit in a common mode inductor can result in the inability to filter out common mode noise signals in the power line, causing interference from other devices. Open circuit is usually caused by coil breakage or poor welding of inductive components.

3. Impedance anomaly: The impedance anomaly of a common mode inductor is usually caused by a short circuit or open circuit in the coil of the inductor component. Abnormal impedance can lead to a decrease in common mode rejection capability, making it difficult to effectively filter out common mode noise.diode