1) Physical quantity 
In electrical engineering, susceptance (B) is the imaginary part of admittance. The inverse of admittance is impedance and the real part of admittance is conductance. In SI units, susceptance is measured in siemens. Oliver Heaviside first defined this property, which he called permittance, in June 1887. ==Formula== where Note: The susceptance is t...
(from the article `reactance`) ...current, total reactance is their difference—that is, = - . The reciprocal of the reactance, 1/, is called the susceptance and is expressed in ...
imaginary part of an admittance Y : B = Im (Y)
the imaginary component of admittance, equal to the quotient of the negative of the reactance divided by the sum of the squares of the reactance and resistance. Symbol: B