I had to test some materials today, so I ran a the standard #73 binocular
core I use in a test to see how much impedance changed with dc bias current.
I could just start to see a change in impedance at 500mA turns. In other
words one turn at 500mA, or 5 turns at 100mA, produced the minimum impedance
change I could resolve on a HP impedance measurement test-set over the
1-30MHz frequency range.
While I still think it is a good idea to keep magnetizing current out of
cores, it doesn't look like normal relay currents would cause a problem. At
some point in the near future I'll run IM curves with both RF power and dc
bias, and post them.
73 Tom
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