Employing the symbol g and b, Y=g-jb = (1/R_P – j/X_P)
Multiplying Y by V to obtain the current I, I=Vg - jVb = V/R_P – jV/X_P

• Vg shown on the above vector diagram is the component of current in phase with the voltage and is the current V/R_Pin the resistive branch of the parallel equivalent of Z_S
• Vb is the component of current in quadrature with the voltage and is the component V/X_P in the inductive branch of the parallel equivalent of Z
• Conductance 1/R_P of the resistive branch of the equivalent parallel circuit is the conductance g of the admittance Y=g- jb=1/Z_S
• Susceptance 1/X_P of the inductive branch is the susceptance b of the admittance Y=1/Z_S.

Observation:

• The conductance g is the reciprocal of R_P but not R_S.
• Similarly susceptance is the reciprocal of X_P and not X_S.