Ferrites and accessories EFD 30/15/9 Core and accessories Series/Type: Date: B66423, B66424 October 2022 TDK Electronics AG 2022. Reproduction, publication and dissemination of this publication, enclosures hereto and the information contained therein without TDK Electronics’ prior express consent is prohibited. EFD 30/15/9 Core B66423 To IEC 63093-14 E core with flattened, lower center leg for especially flat transformer design For DC/DC converters Delivery mode:.