In article , Harold and Susan Vordos says...

The only exception I might make here is that your connections would
certainly be better, considering gold doesn't corrode the way copper and
other elements do. The only problem I've seen is that the typical gold
connector is so thin that it almost wipes off with your fingers. If you
could buy connectors with a thou of gold flashed on, I can't help but think
you'd benefit by not getting noisy connections.

Gold is indeed only a poor third place in conductivity, but it
comes in first place for connector plating, because of its
freedom from oxidation. Gold contacts (gold on gold) are
also self-lubricating which is another reason it is chosen
for switch contacts.

It's not just a noise issue - connectors and switches for
small signal applications need to 'dry switch.' By this
I mean the contact resistance has to be very low, even
for small signals. Most larger power switches will show
a fairly large (fractions of an ohm) contact resistance
until an arc forms and blasts the contact area clean.

The contacts in those switches are often made of an alloy
of silver and cadmium. When I worked at GTE, there was a
man there who did nothing but test different alloys to
try to make contacts that worked as well as the existing
ones, but *without* the cadmium!

Connector and switch manufacturers understand how much gold
has to be put on to give a reliable number of operations
for the device. The thicker the plating, the longer it will
last in service.

Jim


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