[sdiy] Transformer question

[Paul Perry]

You need a closed (or as closed as possible) magnetic loop,
and for any kind of efficiency that means a core of
transformer iron or similar.
All I can imagine working, is two U sections, with the tops
of the Us facing each other across the gap.
(or, similarly, a number of these).

Although, the 'receiving' side could simply be a slab of 
'lossy' magnetic material, if you were just boiling water.

paul perry Melbourne Australia