hi this is saro

[arul_saran]

testing only

[arul_saran]

testing only

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[rajagopal]

testing only

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itsmoked (Electrical) 4 Sep 09 14:41
You are talking about current. The issue with switch contacts is voltage.

The contacts develop oxidation which is a thin layer of non conductive molecules. They, like any insulator, have a stand-off voltage. Depending on what materials the switch contacts are made of, that layer of oxidation will be chemically different. That leads to the various punch through voltages different switches need to reliably switch.

By varying the current you are actually varying the voltage. Once the voltage is great enough you get punch-through.

With most non-gold contacts you need about 10V to reach reliable punch-through. If you try to characterize a switch you are in for a long process. Why? Because you need time between tests for the oxide to form. Also any scuffing of the contacts as they come together alters this response. Furthermore any pitting of the contacts over their life will greatly change the response again.

Generally, if you are a switch user, you need to run 10V or more thru your switches unless;
1) The switches are designed to be self cleaning as they operate

or

2) They have gold contacts.

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