Original poster: "Gregory Peters by way of Terry Fritz <twftesla-at-qwest-dot-net>" <s371034-at-student.uq.edu.au> Hello all, Regarding DC power supplies, can the charging reactor utilise an iron core? I have been told that an iron core will not sufficiently block RF, and that I would need to use ferrite for this purpose. Is this true? Cheers, Greg.