Siemens (unit): Difference between revisions
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*{{cite web|url=http://www.sizes.com/units/siemens.htm|title=Siemens|publisher=Sizes.com|date=2004-12-06|accessdate=2007-06-23}} | *{{cite web|url=http://www.sizes.com/units/siemens.htm|title=Siemens|publisher=Sizes.com|date=2004-12-06|accessdate=2007-06-23}} | ||
*{{cite web|url=http://www.sizes.com/units/mho.htm|title=Mho|publisher=Sizes.com|date=2007-04-21|accessdate=2007-06-23}} | *{{cite web|url=http://www.sizes.com/units/mho.htm|title=Mho|publisher=Sizes.com|date=2007-04-21|accessdate=2007-06-23}} | ||
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Revision as of 10:37, 25 June 2007
The siemens, abbreviated S, is the SI unit of electrical conductance. It is the conductance which will allow a current of one ampere across a potential drop of one volt. The siemens is the reciprocal of the ohm.
The siemens is named for Ernst Werner von Siemens (1816 - 1892), an early pioneer in electrical engineering, and the founder of what has become Siemens AG, a large electrical and electronics firm.
The siemens is a derived unit in the SI, equal to 1 A/V, or Ω-1; or in terms of SI basic units: V = s3·A2·m-2·kg-1 .
Siemens and mho
Before the BIPM approved the siemens as a derived unit in 1971, the common unit for conductance was the mho (ohm spelled backwards), abbreviated ℧. The mho is still in use, despite not having official status, as the upside-down omega is not likely to be confused with lower-case s for seconds, nor for S occuring in formulas.