> I have several toroidial transformers that have two 115v windings and
> two 25v windings on each. The way I understand electricity each 115v
> winding would only go 1/2 way around the toroid then the 25v winding is
> on top of that winding is this correct? or do both windings go all the
> way around? that would be more of a 1:1 isolation transformer (if the
> 25v windings were gone) Am I thinking correctly? Thanks Res.
Best coupling is acheived with all windings going 'all the way round'.
Don't use 2 primary windings for isolation. The insulation used isn't intended
for safety isolation.