A common mode choke is an electronic component used to filter electromagnetic interference (EMI) and radio frequency interference (RFI) from electrical circuits. It is also known as a line filter or a noise filter.
The common mode choke consists of two coils wound on a magnetic core. The coils are wound in such a way that they create a magnetic field that opposes the flow of current in both directions. This means that the common mode choke blocks any current that is common to both the input and output of the circuit, while allowing the differential mode current (the difference in current between the input and output) to pass through.
Common mode chokes are used in a wide range of electronic devices, including power supplies, audio equipment, and data communication systems. They are particularly useful in applications where electromagnetic interference and radio frequency interference can cause signal distortion, noise, or other problems.
By blocking unwanted noise and interference, common mode chokes can improve the performance and reliability of electronic systems. They can also help to ensure compliance with electromagnetic compatibility (EMC) standards, which are designed to limit the amount of interference that electronic devices can generate and be susceptible to.