- Susceptance
In
electrical engineering , the susceptance ("B") is the imaginary part of theadmittance . InSI units, the susceptance is measured in siemens.Oliver Heaviside first defined this property, which he called "permittance", in June1887 Fact|date=October 2007.Formula
The general equation defining admittance is given by:Y = G + j B ,
where:"Y" is the
admittance , measured in siemens (a.k.a. mho, the inverse of ohm).:"G" is the conductance, measured in siemens.:"j" is theimaginary unit , and:"B" is the susceptance, measured in siemens.Rearranging yields
:B = frac{Y - G} {j}.
But since
:frac{1}{j} =frac{j}{j cdot j} = frac{j}{-1} = -j,
we obtain
:B = -j cdot (Y -G) .
The admittance ("Y") is the inverse of the impedance ("Z")
:Y = frac {1} {Z} = frac {1} {R + j X} = left( frac {R} {R^2+X^2} ight) + j left( frac{-X} {R^2+X^2} ight) ,
or:B = Im(Y) = left( frac{-X} {R^2+X^2} ight)
where
:Z = R + j X ,:"Z" is the impedance, measured in ohms:"R" is the resistance, measured in ohms:"X" is the reactance, measured in ohms.
Note: The susceptance is the imaginary part of the admittance.
The magnitude of admittance is given by:
:left | Y ight | = sqrt {G^2 + B^2} ,
ee also
SI electromagnetism units External links
* [http://www.geocities.com/SiliconValley/2072/eleccsa.htm Conductance, Susceptance, and Admittance]
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