In electrical engineering, admittance Y is the inverse or reciprocal Y = Z−1 = 1/Z of impedance Z. Just as impedance is complex resistance, and conductance G is the inverse G = 1/R of resistance R, admittance is also complex conductance.
Likewise, admittance is made up of a real part (the conductance), and the imaginary part called susceptance B, shown by the equation Y = G + jB.