>You'll need about 700 gauss IIRC.
>
>700 turns at 1A would get you there. Wind a solenoid big enough to put
>the

1A at 220V is 220W (ok, I know it's a coil). This is slightly less than
the 300W I came up with. However I seem to remember that high remanence
materials require more like 1400 Gauss and more but I am not sure. 700
Gauss is Iron ?

The idea is not to make an airwound coil, instead it's a transformer for
~300W with only the primary wound and the E cores all assembled from the
same side. This yields a large magnet with a respectable field across the
open ends of the Es. I have one of these at work and they almost work (too
little power spec to erase VHS tapes and floppies, but everyhting else is
ok).

Am I wrong if I say that one cannot erase a higher magnetization material
using pole pieces made of a lower magnetization material ? I think that a
strong enough field cannot be achieved ?

Which probably leaves the aircoil mounted in a power oscillator at ~1MHz.
I can see an use for a PL509 I have here ...

Peter

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