The role of common-mode inductors
Common-mode inductors can be used to filter out common-mode interference signals in circuits. In electronic circuits, common-mode interference often arises due to power interference and signal line interference, which can degrade signal quality and affect the normal operation of the circuit. The role of common-mode inductors is to enhance the circuit's anti-interference capability by filtering out common-mode interference signals, ensuring accurate transmission of signals.
Specifically, common-mode inductors can filter out the frequency range of common-mode interference signals, i.e., the shared portion of the interference signal. Their working principle is to utilize the characteristics of inductance to block the passage of common-mode interference signals. When common-mode interference signals pass through a common-mode inductor, due to the inductive impedance characteristics, an opposite electrical potential is generated, thereby canceling out the interference signal and preventing its further transmission to other parts.
Two: Principle of Common-Mode Inductors
The principle of common-mode inductors primarily involves the working principle of inductors and the characteristics of common-mode signals. An inductor is an element that stores magnetic energy. When current flows through the wire passing through an inductor, a magnetic field is generated, which is stored within the inductor. As the current changes, the magnetic field also changes, thereby producing an induced electromotive force. The direction of this induced electromotive force is opposite to the direction of the current change. Therefore, inductors can filter out interference signals by resisting changes in current.
Common-mode signals refer to the shared portion of a signal. In electronic circuits, signals are often transmitted through signal lines, and these lines may be subjected to interference from other signals, leading to a degradation in signal quality. Among these interfering signals, there is a portion that is common, meaning it exists simultaneously on both the signal line and the ground line. The characteristics of common-mode signals include a relatively lower frequency range and smaller amplitude. Therefore, filtering out common-mode signals can enhance the quality of the signal.
