Re: Solid State coils.

Hi all,
       This is a slight addition to my previous post on this topic.
I should have included a couple of notes on the design of ferrite
transformers. The typically low inductance of the windings compared
with the overall leakage inductance mandates certain construction 
teahniques  for best results. Firstly, both halves of the primary
should be bifilar wound to couple as closely as possible. Secondly,
the secondary is often sandwiched in between layers of primary, a 
typical arangement being to wind half the primary turns (for each 
primary half), then insulate, then wind the secondary, more 
insulation, then wind the rest of the primary windings on top. In the 
best designs, even the secondary can be sectionalized and and 
interleaved with the primary. The extra insulation required to do 
this plus the inter-layer creepage distance can severely restrict the 
number of windings one can actually get on a given core. For example, 
in SMPS transformers complying with international hipot specs, the 
windings can occupy less than half the available winding window. 
Whole books have been written on the subject. For Alan's application, 
I think the primary should at least be bifilar wound if nothing else.