Editing Switch (section)

===Wetting current===
{{Main|Wetting current}}

''Wetting current'' is the minimum current needing to flow through a mechanical switch while it is operated to break through any film of [[oxidation]] that may have been deposited on the switch contacts.<ref>Gregory K. McMillan (ed) ''Process/Industrial Instruments and Controls Handbook (5th Edition)'' (McGraw Hill, 1999) {{ISBN|0-07-012582-1}} page 7.26</ref> The film of oxidation occurs often in areas with high [[humidity]]. Providing a sufficient amount of wetting current is a crucial step in designing [[Control engineering|systems]] that use delicate switches with small contact pressure as sensor inputs. Failing to do this might result in switches remaining electrically "open" due to contact oxidation.