Re: [TCML] Stranded/silver plated wire (was Scientific Method)

[DC Cox <resonance@xxxxxxxxxxxx>]

I use the 19 strand silver tinned type wire usually in 14 to 18 AWG on many
of my high power coils.  The 7 strand is not adequate.

Dr. Resonance




On Tue, Jul 28, 2009 at 8:44 PM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:

> Lau, Gary wrote:
>
>> Are you saying that you use silver-plated STRANDED wire for
>> secondaries?  Granted, AC resistance and Q are far less important on
>> the secondary side, but the notion of this wire being superior to
>> common magnet wire is incorrect.  Stranded wire is inherently more
>> lossy at RF frequencies.  This is because the skin effect causes
>> current to travel on the outer surface of the bundle.  If a strand on
>> the outside of the bundle weaves to the interior of the bundle, the
>> current in that strand will try to find its way back to the surface,
>> and this means traveling to adjacent conductors, through any
>> resistive oxide layers between them.  This strand-hopping results in
>> a much higher AC resistance than if a single conductor were used.
>> This is the reason that Litz wire insulates the strands from one
>> another.
>>
>
> Most stranded wire is NOT braided. It's something like 7 strands, so the
>  outside strands stay outside. THe other thing is that 100kHz-ish
> frequencies have a fairly thick skin depth (0.2 mm in copper). It's not like
> at 15 MHz where skin depth is a few tens of microns.
>
>
>
>
>
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