TDK Corporation is a Japanese multinational electronics corporation that manufactures electronic components and recording and data-storage media. Its motto is "Contribute to culture and industry through creativity".

A ferrite is an iron oxide-containing magnetic ceramic material. They are ferrimagnetic, meaning they are attracted by magnetic fields and can be magnetized to become permanent magnets. Unlike many ferromagnetic materials, most ferrites are not electrically conductive, making them useful in applications like magnetic cores for transformers to suppress eddy currents.