On Wednesday 19 January 2005 01:41 pm, Karel Kulhavy wrote: > 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
You could try some of this new Peratech material: http://www.peratech.co.uk/pills.htm The follow discusses switches, but the same idea could apply to a bulk-head style connector. They have some other cool products as well. Seems to be a material in search of an application... " Retrofittable Components for Improved Switching Performance The basic design of low power switches has not changed substantially over many years. However the advent of QTC now allows switch manufacturers to easily add new functionality to existing switch designs or to develop new, simpler, more reliable designs. Making Contact Most mechanical switch designs involve the physical coming together of two contacts to complete the circuit. QTC allows a different approach to be taken. QTC is essentially a non-conductor in its normal state. However, under pressure, QTC starts to conduct and under sufficient pressure its resistance drops to less than 1 ohm. This property allows switches to be constructed that essentially have no contacts. However, it also allows for improvement to existing designs by interposing QTC Pills between the existing contacts in a switch. Soft Start Because QTCâs resistance doesnât drop instantly but drops away exponentially as pressure increases, this enables the current through the switch to slowly increase as the switch is closed, giving a soft start. No Arcing The same mechanism, combined with the fact that there is no physical contact gap required, serves to ensure that there is reduced possibility of arcing, which improves safety and contact life. Proportional Control The gradual drop in resistance described earlier allows for a standard switch to offer full proportional control of a load. An existing momentary spring-loaded switch can be âupgradedâ to provide proportional control simply by inserting a QTC Pill between the existing contacts. Direct uses therefore include, for instance, controlling the speed of a motor or brightness of a lamp. "
