ferrite core inductor
https://www.openlearning.com/u/matsuda-qaldlu/blog/HowSuccessfulPeopleMakeTheMostOfTheirEmiSuppressionFerriteCore/
A ferrite Main is really a type of transformer that's Employed in modest transformers. It could be named a hollow Main or semi-rigid core. It provides a Main or envelope with hooked up plates which are hinged.