Understand the differences between common mode inductance and differential mode inductance in three aspects
Time:2022-03-02
Views:2268
In filters, switching power supplies and other products, in order to resist electromagnetic interference, we often use two components, common mode inductance and differential mode inductance. What are the differences between the two? We can find a lot of these on the Internet. Today, Xiaobian has made some rules through the knowledge points and some of his own understanding, and made a comparison from the functions, characteristics, appearance and winding methods of the two, hoping to make you better distinguish between common mode inductance and differential mode inductance.
1. Different functions
The disturbance electromagnetic field generates common mode current between line and ground. The common mode current generates differential mode voltage on the load and causes interference. This is common mode interference. The function of common mode inductance is to suppress common mode interference.
The disturbing electromagnetic field generates differential mode current between lines and causes interference on the load, which is called differential mode interference. The function of differential mode inductance is to suppress differential mode interference.
2. Different appearance and winding methods
Common mode inductance is wound on the same core, and the coil diameter of the two windings is the same as the number of turns, but the winding direction is opposite. A group of coils has two pins, so the common mode inductance will have four pins.
Differential mode inductance is wound on an iron core and has only one coil, so it has only two pins. Therefore, common mode inductance and differential mode inductance can be distinguished from the number of pins.
Characteristics of common mode inductance: because the winding directions of two groups of coils on the same core are opposite, the core is not afraid of saturation. High conductivity ferrite material is the most used magnetic core material in the market.
Characteristics of differential mode inductor: it is used in high current occasions. Because it is wound in an iron core supplier, when the current flowing into the coil increases, the iron core of the coil will be saturated. Iron powder core material is the most used iron core material in the market, because the price is very cheap.
The above three aspects are the differences between common mode inductance and differential mode inductance summarized by Xiaobian. Is it easy to understand? Of course, there are other different places, so we won‘t repeat them one by one. You can try whether the Xiaobian summary is right or not!
1. Different functions
The disturbance electromagnetic field generates common mode current between line and ground. The common mode current generates differential mode voltage on the load and causes interference. This is common mode interference. The function of common mode inductance is to suppress common mode interference.
The disturbing electromagnetic field generates differential mode current between lines and causes interference on the load, which is called differential mode interference. The function of differential mode inductance is to suppress differential mode interference.
2. Different appearance and winding methods
Common mode inductance is wound on the same core, and the coil diameter of the two windings is the same as the number of turns, but the winding direction is opposite. A group of coils has two pins, so the common mode inductance will have four pins.
Differential mode inductance is wound on an iron core and has only one coil, so it has only two pins. Therefore, common mode inductance and differential mode inductance can be distinguished from the number of pins.
3. Different characteristics
Characteristics of common mode inductance: because the winding directions of two groups of coils on the same core are opposite, the core is not afraid of saturation. High conductivity ferrite material is the most used magnetic core material in the market.
Characteristics of differential mode inductor: it is used in high current occasions. Because it is wound in an iron core supplier, when the current flowing into the coil increases, the iron core of the coil will be saturated. Iron powder core material is the most used iron core material in the market, because the price is very cheap.
The above three aspects are the differences between common mode inductance and differential mode inductance summarized by Xiaobian. Is it easy to understand? Of course, there are other different places, so we won‘t repeat them one by one. You can try whether the Xiaobian summary is right or not!
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