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Re: simple question RF gnds





O> Wire resistance at DC is a constant and very low,
> Effecting a low Z (impedance) requires using a large surface area 
> due to 
> skin affect conduction occurring only around a thin surface area of 
> metal
> conductors

I don't know about macro sized tubes such as used in a TC primary, but on
copper strips on a pc motherboard the skin effect only becomes
apparent(meaning lossy) around the gigahertz range.

>   (one reason the Pri can be "hollow" copper tubing - solid center
> contributes little)
>    becoming more important as frequency increases 
>    (note the "frequency" may not be obvious i.e. it relates to that 
> of the
> highest freq component 
>     occurring say, in a discharge or a spark gap, 
>     each possessing much higher freq's than TC pri/sec resonant 
> freq's)
> 
> so wide copper straps (silver coated=very best) are preferred 
> followed by 
>    Litz wire (lots of insulated wires bundled together effecting a 
> large
> surface area)

I think litz wires were one of Nikola Tesla's inventions.  Either that or
he just used them a lot.  They also have decreased inductance because
each wire is like a inductor and when you put them in parallel 1/N*L.  N
is the number of wires and L is the inductance of a single wire of the
strand.  Unless because it is twisted this increases inductance, but I
don't know if this is significant or not.  Decreased inductance decreases
AC resistance or reactance.

Bryan

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