Re: Secondary Question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Nolley by way of Terry Fritz <twftesla-at-qwest-dot-net>" <nolleym-at-willamette.edu>

> Hi list,
>
> Just curious if anyone has considered or has wound their secondary coil using
> the "bifilar" technique, where two wires are wound side by side and connected
> at the ends instead of one continuous wire wound end-to-end.
>
> Is there any advantage to using this technique vs the standard, usual way of
> winding?

    I'm not an engineer or any kind of expert on the issue, but my
impression has
  been that multiple strands can carry more current.  The advantage of
doing this over simply
winding a larger gauge magnet wire is that the insulation between the two
wires constitutes
another surface along which the rf energy can flow.  In other words, if you
have 2 wires which
together have the width of--say 22 ga. magnet wire, they will conduct more
current than the 22
ga. will.  I may be wrong about this.
    I recall that Richard Hull used to wind his magnifier secondaries with
Litz wire (braided
strands of individually insulated wire) which is another way of increasing
the current path
without substantially increasing the size of the wire.
    Some magnifier drivers are wound with 2 layers which are connected
together.  This is a
good strategy for larger gauge driver secondaries which may use rectangular
wire.  Situating
the windings so that the number of turns is the same becomes much easier
this way.
                Hope this helps.
                        --Mike