Common Mode Inductance

- Sep 11, 2018 -

The role of magnetic ring: the magnetic ring has different impedance characteristics at different frequencies. Generally, the impedance is very small at low frequencies. It makes the normal useful signal pass well and can restrain the high frequency interference signal pass well. But the magnetic ring inductance itself USES the current to be higher, the inductance value can also do high, and itself to the circuit requirements higher also can achieve, so the magnetic ring inductance is relatively extensive. However, there are two kinds of magnetic ring inductors, many people are relatively vague concept, this is the differential mode inductance and common mode inductance, what is the difference between them?

1. Different inhibiting interference signals. The disturbing electromagnetic field generates the difference mode current between the line and the line, which causes interference on the load. The disturbance electromagnetic field generates the common mode current between the line and the ground, and the common mode current produces the difference mode voltage on the load, causing the interference, which is the common mode interference. The magnetic ring inductors that inhibit common mode interference are called common mode inductors, while the magnetic ring inductors that inhibit differential mode interference are called differential mode inductors.

2. The manufacturing process is different. Common mode inductance is two sets of coils with equal winding number, equal wire diameter and opposite direction. Differential mode inductance is a coil wound around a core.

3. Different features. Common mode inductors are characterized by the fact that the two coils on the same core are wound in opposite directions, so the core is not afraid of saturation. The most widely used magnetic core material on the market is ferrite material. Differential mode inductors are characterized by their use in high-current situations. Because of a coil wound on an iron core, the core in the coil becomes saturated as the current flowing into the coil increases, so the most widely used iron core material on the market is metal powder core material, especially iron powder core material (due to its low price).