Silver oxide is slightly conductive but not by very much. Depending upon
where you live and what fuel you use to heat your house and cook with,
the black tarnish on silver is more likely to be silver sulfide because
of the sulfur content in heating oil and natural gas. Natural gas has no
odor and a sulfur bearing compound added to it to make it smell. Think
essence of skunk.
Silver sulfide is many orders of magnitude more conductive than silver
oxide.
David
KW4DH
On 3/24/2011 9:47 AM, GEORGE WALLNER wrote:
> On Tue, 22 Mar 2011 13:06:04 -0700
> "John Lyles"<jtml@losalamos.com> wrote:
>> I'm pleased that Rob specified "in a HF tank circuit"
>> for his comment "they are so nearly the same that copper
>> strap is good enough; silver just looks pretty and
>> impresses people."
> Although for practical purposes on HF this is mostly true,
> there is a difference. Copper oxide is an insulator while
> silver oxide is a conductor. As the copper oxidizes, the
> skin current encounters increased resistance and moves
> deeper into the copper. At HF the difference will be very
> small.
>
> I have tested both bare copper and silver plated
> inductors, trying to measure the difference in Q, and with
> high RF currents (10 - 12A at 1.8 MHz) trying to measure
> the heating difference. I could never tell between the
> two. I have also tried to see if the Q of tarnished copper
> inductors was lower, but again, the differences were not
> measurable with my set-up. Still, I prefer silver plated
> inductors. It must be the looks. (I have also tested
> powdered-iron-core inductors. Even with silver plated wire
> they had lower Q-s (200 - 250) and heated up
> considerably.)
>
> 73, George, AA7JV
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--
“I bring reason to your ears, and, in language as plain as ABC, hold up truth
to your eyes.” Thomas Paine, December 23, 1776
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