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Simply speaking, a switch or circuit breaker are two metallic contacts (electrodes) that are in GALVANIC CONTACT with each other when closed and separated by a certain distance when open.

I don’t really get what galvanic means in this contest. I thought the term galvanic was used in relation for a production of a direct current by chemical reaction (galvanic cell), but in a circuit breaker there is no DC electrical production, so what other meaning has galvanic?

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    \$\begingroup\$ The term usually refers to bimetallic contact, that may lead to corrosion. \$\endgroup\$ – Chu Dec 25 '17 at 9:40
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You're right about galvanic cells, but the word has picked up other usages. As usual with human language, there's no guarantee of logical consistency in these developments.

Galvanic contact and galvanic isolation simply refer to the presence or absence of a direct electrical connection. That is, a current through a conductor, rather than a connection via capacitive or inductive coupling, optical coupling, and so on.

In my experience, galvanic isolation is much the more common term. For example, transformers and optocouplers provide galvanic isolation. Galvanic contact makes sense as a consistent antonym, but I haven't seen it used anywhere near as much.

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This sounds like a direct metal to metal Ohmic contact. Most practical switches and contacts are matched to avoid oxidation and Galvanic corrosion, which can cause loss of contact.

Calling it a Galvanic contact probably is to attribute it to Luigi Galvani, who made some important electrical discoveries.

Here are a couple of references from Google:

"Dictionary:Galvanic contact - SEG Wiki https://wiki.seg.org/wiki/Dictionary:Galvanic_contact Feb 17, 2017 - An actual electrical contact with the ground, as opposed to inducing electric current flow by induction. Called an ohmic contact if linear and rectification is not involved. Named for Luigi Galvani (1737–1798), Italian anatomist. Retrieved from ..."

"Ohmic contact - Wikipedia https://en.wikipedia.org/wiki/Ohmic_contact An ohmic contact is a non-rectifying electrical junction: a junction between two conductors that has a linear current–voltage (I-V) curve as with Ohm's law. ‎Physics of formation of ... · ‎Preparation and ... · ‎Technologically important ..."

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  • \$\begingroup\$ hi new user, good answer, have some rep. \$\endgroup\$ – Neil_UK Dec 25 '17 at 11:49

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