Admittance
To simplify mathematical manipulation, calculation, and analysis, it is sometimes convenient to express the impedance as its reciprocal quantity, or admittance. Admittance is defined as
Y = 1/Z = I/V
and can be written as
Y = G + jB
where G and B are the rectangular (real and imaginary) components, known as conductance and susceptance respectively. The conductance G is the reciprocal of the parallel resistance, as follows:
G = 1/RP
The susceptance for capacitors is expressed as follows:
BC = 2
fCP = 1/XC
The susceptance for inductors is expressed as follows:
BL = 1/2fLP = 1/XL