[Boatanchors] [Milsurplus] Relay question

[Jim Haynes]

Depending on contact material, relay contacts may need a certain amount
of voltage and current to break down insulating films that can form.
There have especially been problems with sealed relays, because the
material used to encapsulate the coil can give off fumes that cannot
escape and contribute to forming insulating films.  Sometimes contacts
are gold plated to resist the formation of oxide films.

A good treatment of this topic is in Western Union Technical Review,
vol. 15 no. 4, October 1961, p. 149 "Investigation of Electrical Contacts
in Low Power Level Circuits" by J.hn J. McManus.  Western Union Technical
Review can be found at
telecom.csail.mit.edu/archives/technical/western-union-tech-review/




jhhaynes at earthlink dot net