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RE: RF resistance of secondary coil
Matt,
There are two effects at play, one is "skin-effect" whereby the current
is forced to flow near the surface of the wire, there are formulae for
this, the simplest I know is;
sd=66/SQRT(Freq in Hz) mm
which is about 0.12mm -at- 300 kHz.
Calculate resistance as if all of the current is evenly distributed
within this "skin" (it's not, but the formula takes care of that). So
large surface area conductors are used, such as copper tubing. There are
many tables that will give h.f. resistance as a function of frequency
and wire size.
Unfortunately (in terms of theoretical calculation) there is the
"proximity effect" which is dependant upon the interaction of the
magnetic field caused by the entire winding, and especially by adjacent
wires. I believe that for a close wound coil such as a TC secondary a
near approximation is to QUADRUPLE the effective resistance.
In any case we need not go into too much detail on secondary 'Q' as the
corona alone will drastically reduce 'Q', streamers kill it. If the
secondary maintained it's 'Q' during operation it would be extremely
boring (no power out/lost = no arcs).
That concludes the opinion of a non-expert, if our guru's here offer
other opinions, follow that instead! bye ... Sulaiman
> Does anybody have a formula to find the RF resistance of the secondary
> coil's wire. I want to make some detailed calculations on my coil's
> Q, but I need a way to find the wire's resistance at 300 kHz.
> Wouldn't this be dependent upon the frequency and dimensions of the
> wire?
>
> Matt Behrend
>
>