Flat cable ferrite cores are made from the ceramic material ferrite and are used to eliminate noise on flat cables, such as flat ribbon cables. Ferrite cores help to prevent electromagnetic and radio frequency interference, which can otherwise cause problems for low-level signals.
Flat cable ferrite cores are easy to attach to cables. You can simply thread the device over your cable and then apply the plug connectors that are usually provided. The ferrite core is held in position with heat-shrink sleeving, a metal clamp or adhesive tape, or you can glue it in place instead.
Flat cable ferrite cores are most commonly used in the cores of radio frequency transformers in applications such as switched-mode power supplies and ferrite antennas for AM radio receivers.