Subject: Re: Reducing contact resistance for low volt use?
Summary: What do you think of these ping times eh?
Reply-To: You can't see me, and I pass right through planets...
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Date: Tue, 07 Jan 2003 04:16:14 GMT
NNTP-Posting-Date: Mon, 06 Jan 2003 23:16:14 EST
On Mon, 06 Jan 2003 15:20:41 GMT, firstname.lastname@example.org (John Fields) Gave
>I don't believe I made any mention of the reason the military uses
>it all. However, if you'd like to start a thread on that subject
>I'd be glad to join in.
For the silver at 24 gauge it is 25.2 ohms per 1000 feet
For copper (bare) at the same gauge, it is 25.67 ohms per 1000 feet.
That is a 2% difference. Down near zero volts, however, the
difference is significant for the load end of the circuit. I know...
you are going to tell me how little a one foot length has. I would
only say that silver has a little less. Resistance, that is.
This spec drops to near zero volts.
As for the reasons for silver on wire in the military, it was
originally used soled in transmitter equipment initially because the
cost for silver was a lot higher back then. It has since migrated to
power cabling for corrosion resistance reasons, mainly.
One of the mentions in the mil specs are susceptibility to "rd
plague" corrosion, A galvanic response at the copper/silver interface.
No electrical stimulus needed. It surround plating thickness and
integrity as oxygen seems to be the culprit. I guess that is why they
call it "oxidation".
I'm sure there are many other factors. Another good one is that SPC
is far more solderable (especially over time and environ)than is TPC
or straight copper even. It remains "wettable" longer.