[Lowfer] Borers on Ferrite - LOWDOWN

[Peter Barick]

LowFERS,
Re: "Ferrite Facts," By Bill Bowers In April 2002 LOWDOWN

Parts 2 and 3 of the experiments on ferrite toroid transformers by
LowFER Bill Bowers appeared in the current issue of LOWDOWN and is
appreciated for the information and the precision that an engineer like
Bowers brings to the table. My only other source of helpful info on
ferrite design/use has been the Amidon Data sheet that opens like a
street map and is about as handy to use as a tissue in a stiff wind.

But somewhat confusing in Part 3 is the text on winding primary and
secondary turns. He talks about a twisting 3 strands for SEC and 1 for
PRI together and winging this "trifilar" group on the core. I can't
comprehend how 4 strands are a "trifilar" winding, and if the secondary
is "trifilar," why are the 3 wires needed instead of just one? Why is
this technique being used?

I don't think Bowers is on this list, so I toss this to others.
Thoughts?

Cheers, Peter