Ferrite cores (chokes) provide an inexpensive, and effective, way of coupling high-frequency resistance into a cable in order to reduce the common-mode current, and hence the radiation (or pickup) from the cable.

Why is a ferrite core used in cables?

Ferrite beads and cores are used in equipment design to suppress and dissipate high frequency noise levels caused by electromagnetic devices. Ferrite components are used to attenuate EMI and can be extremely effective. Of course, using properly installed and grounded shielded cables helps suppress EMIs.

Why ferrites are used?

Ferrites are one of the main core materials used in inductors and transformers. Inductor ferrite is used to provide an increase in the permeability of the medium around the coil to increase the inductance of the inductor. Ferrites are widely used within inductor technology to improve the performance of the inductor.