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Re: Primaries and Copper Tubing

Subject:   Re: Primaries and Copper Tubing
  Date:    Fri, 25 Apr 1997 09:03:24 -0500
  From:    David Huffman <huffman-at-FNAL.GOV>
    To:    Tesla List <tesla-at-pupman-dot-com>


Bert,
I like the gold plating idea, geometric polished metal objects are an
art
form to me.
If we ever find a good switch for the primary then we can explore high Q
primaries.
Dave 

> 
> 
> Dave and all,
> 
> Remember how nice, bright, and shiny your copper-tubing primary looked
> when you first made it? Then it oxidized, to its normal, dull patina. 
> If you bothered to silver plate it, the silver tarnishee and also looks
> grungy after a while. BUT, suppose you gold-plated copper tubing, just
> think how beautiful it would stay! A thin overcoat of gold should have
> minimal effect on the effective resistance of the primary. For copper,
> the "skin depth" at 100 kHz on a cylindrical conductor is a little over
> .008". A 1 mil thick gold-plated layer will have negligible impact on
> the effective electrical performance of the primary but would have a
> dramtic impact on its long-term appearance. Might be a nice touch for a
> museum coil...
> 
> BTW, because the gap losses so dominate the Q of the primary system,
> even using aluminum tubing would have minimal impact on coil
> performance. But you probably wouldn't want to use a carbon primary -
> winding is a real pain - talk about work hardenning! :^)
> 
> Safe coilin' to you!
> 
> -- Bert --
> 
> 
> 
> Tesla List wrote:
> > 
> > Subject:  Re: Primaries and Copper Tubing
> >   Date:   Wed, 23 Apr 1997 11:27:22 -0500
> >   From:   David Huffman <huffman-at-FNAL.GOV>
> >     To:   Tesla List <tesla-at-pupman-dot-com>
> > 
> > Gold is only slightly better than aluminum in resistivity. The one
> > reason
> > it is used in electronics is its resistance to corrosion. Silver is the
> > best conductor ignoring superconductors. It would be pretty hard to
beat
> > good old copper tubing!
> > In the primary isn't there a few ohms of resistance at the spark gap?
In
> > a
> > series circuit the primary resistance seems to be a small part of the
> > total.
> > 
> > silver   p=1.59 microhm-cm
> > copper   p=1.67 microhm-cm
> > gold     p=2.35 microhm-cm
> > aluminum p=2.65 microhm-cm
> > iron     p=9.71 microhm-cm
> > tungsten p=42.0 microhm-cm
> > carbon   p=1375 microhm-cm
> > 
> > ----------
> <Original post re: Gold primary SNIPP'ed>
>