Well, I'm certainly no expert but it seems to me that the secondary induction is not caused by the primary's E field but rather by change in the magnetic vector potential or A field in the center of the toroid over time or dA/dt . It isn't just the A field at the center of the toroid (although it has maximum value there) but the whole circular A field that goes around the core and passes through the center (as does the secondary conductor). IOW there is an A field alternating in value hence an E field all along the secondary wire. The question then would be- is the A field able to be shielded? No it can't be shielded in the normal sense of a shield. But it can be almost negated and the easiest way to do this is to make the shield a shorted turn. Then the current induced into that shorted turn produces an additional A field that opposes the original one, and that opposing A field has curl so there is also a B field opposing the applied B field in the core. The poor old primary now has a hard time trying to drive any flux into the core. Smudge
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Topic: Kirchhoff is for the birds... (Read 27198 times)
