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Re: gEDA-user: Contact reliability



The way that you guarrantee contact reliability is by forcing current to flow, every time the contact points are moved. This causes microscopic welds.

Relays for aircraft use have a specification for minimum current, for this purpose.


Karel Kulhavy wrote:

Hello

What are the conditions under which 100% reliable contact between two metals
is guaranteed? My hypothesis is that there are only two possibilities:

1) gold-to-gold
2) The touch point is under permanent great preload which causes the crystal
lattices to deform plastically and be fused together (like in wire nuts -
you can see the denting on the wire)

The contact is supposed to be generally subject to high-amplitude thermal
cycles (-30 to +70 degC) for years with very difficult maintenance. It
won't be subject to condensing humidity or direct weather exposure. And
must be repeatedly disassemblable without soldering.

Cl<