The difference between common-mode inductors and differential-mode inductors

1. The differential-mode interference signal is a current loop signal formed in the opposite direction between the two input power lines, and the common-mode signal is a current loop signal formed in the same direction between the two input lines and the earth.
2. Simply put, the differential mode is a signal that is transmitted between the two main lines of the loop, and the signals on the two main lines are opposite. The common mode is that the signal phases of the two main lines are the same.
3. Common-mode inductors are generally wound in two-way bidirectional lines; differential-mode inductors are wound in one direction.
4. The filter inductor that suppresses common-mode interference is called a common-mode inductor; the filter inductor that suppresses differential-mode interference is called a differential-mode inductor.
5. The two sets of coils with the same number of turns, the same wire diameter, and opposite windings on the same core are common-mode inductors; differential-mode inductors are a coil wound on an iron core.

Secondly, from the appearance point of view, the most obvious difference between the two can be found: common-mode inductors have 4 pins, and differential-mode inductors have 2 pins. Then let’s introduce some details:

1. Common-mode inductors are two windings, with the same input and output, and the same-named ends are generally located on the same side of the magnetic ring;
2. The number of turns of the common-mode inductor windings is the same. If the distribution is asymmetrical, it is not a common-mode inductor;
3. If the wiring is wrong, the common-mode inductor will be ineffective.

Now, let’s summarize the characteristics of common-mode inductors and differential-mode inductors to help you better distinguish them.

Characteristics of common-mode inductors: Since the two sets of coils on the same core are wound in opposite directions, the core is not afraid of saturation. High-conductivity ferrite materials are the most commonly used magnetic core materials on the market.

Characteristics of differential-mode inductors: When used in high-current situations, because the coil is wound on a core, when the current flowing into the coil increases, the core of the coil will saturate. Iron powder core material is the most commonly used core material on the market, mainly because the price is relatively cheap.

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