ferrite core

One of the commonly used cores in switching power supply transformers and choke coils. The most widely used type of ferrite is spinel ferrite, which is represented by the molecular formula MO·Fe2O3 (M is a divalent metal). Spinel ferrite cores are manufactured by placing powdered metal oxides into molds, compacting them, and firing them. Spinel ferrites are often produced by mixing multiple metal materials to increase saturation magnetic flux density and are called composite ferrites.

Ferrite cores are suitable for output transformers and transformers with large current variations because they have the advantage of low iron loss even with large changes in magnetic flux density in high-frequency regions. On the other hand, they have the disadvantage of lower saturation magnetic flux density compared to metal cores.

Also, the core attached to the DC cord as EMI (noise) countermeasure for AC/DC Power Adapters — Desktop & Wall-Mount is called a ferrite core.