spaco wrote:

I was just looking up expansion rates of metal for another post. The
next column in the Machinery's Handbook lists electrical conductivity
ratings. I have worked with electricity in one way or another, most of
my life, but I never realized how poorly some metals that are commonly
associated with electrical connections are!

With Silver as Conductivity = 100,
Copper = 97.61 Yup.
Lead = 8.42 !!! No wonder car batteries get hot!!!
Tin =14.39 !!! Lead and tin are the main constituents of most soft
solders. If you ever needed a case for making a good mechanical joint
before soldering, there it is!

Oh-- page 2193 of the 19th edition.

Pete Stanaitis


I 'spect that the usually thin sections and its intimate contact with
materials having high thermal conductivity makes the poorer electrical
conductivity of lead/tin solders not such a beeg problem, 'eh?

P.S. I heard somewhere recently that someone calculated that there's
more copper existing in wiring and plumbing in the USA than remains in
the known national reserves. Can anyone confirm that?

Jeff (Who remembers visiting that big open pit copper mine in
Coppertown, Utah circa 1955.)

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."