Siemens (unit)

From Wikipedia, the free encyclopedia.

The siemens (symbol: S) is an SI derived unit of measurement for electric conductance, being the inverse of the ohm (Ω), named after Werner von Siemens.

S = siemens
A = amperes
V = volts

The forumla for computing conductance is as follows:

G = 1 / R = S

G = Conductance
R = Resistance (ohms, Ω)
S = siemens

Example: G = 1 / 6 Ω = 0.1667 S

Mho is a now eccentric name for this unit of electrical conductance, equal to 1 Ω⁻¹. It is derived by spelling ohm backwards. Its symbol is the upside-down letter Ω <math>\mho<math> ℧ (U+2127). The term siemens is used universally in science and primarily in electrical applications, while mho is used primarily in electronic applications.

[edit]

SI electricity units

SI electromagnetism units edit (http://wikipedia.cas.ilstu.edu/index.php?title=Template:SI_electromagnetism_units&action=edit)
Name	Symbol	Dimensions	Quantity
ampere (SI base unit)	A	A	Current
coulomb	C	A�s	Electric charge, Quantity of electricity
volt	V	J/C = kg�m²�s⁻³�A⁻¹	Potential difference
ohm	Ω	V/A = kg�m²�s⁻³�A⁻²	Resistance, Impedance, Reactance
ohm metre	Ω�m	kg�m³�s⁻³�A⁻²	Resistivity
watt	W	V�A = kg�m²�s⁻³	Electrical power
farad	F	C/V = kg⁻¹�m⁻²�A²�s⁴	Capacitance
farad per metre	F/m	kg⁻¹�m⁻³�A²�s⁴	Permittivity
reciprocal farad	F⁻¹	kg¹�m²�A⁻²�s⁻⁴	Elastance
siemens	S	Ω⁻¹ = kg⁻¹�m⁻²�s³�A²	Conductance, Admittance, Susceptance
siemens per metre	S/m	kg⁻¹�m⁻³�s³�A²	Conductivity
weber	Wb	V�s = kg�m²�s⁻²�A⁻¹	Magnetic flux
tesla	T	Wb/m² = kg�s⁻²�A⁻¹	Magnetic flux density
ampere per metre	A/m	m⁻¹�A	magnetic induction
ampere-turns per weber	A/Wb	kg⁻¹�m⁻²�s²�A²	Reluctance
henry	H	Wb/A = V�s/A = kg�m²�s⁻²�A⁻²	Inductance
henry per metre	H/m	kg�m�s⁻²�A⁻²	Permeability
(dimensionless)	χ	-	Magnetic susceptibility