The real part of the admittance of an alternating-current circuit. The admittance Y of an alternating-current circuit is a complex number given by Eq. (1).
The real part G is the conductance. The units of conductance, like those of admittance, are called siemens or mhos. Conductance is a positive quantity. The conductance of a resistor R is given by Eq. (2).
In general the conductance of a circuit may depend on the capacitors and inductors in the circuit as well as on the resistors.For example, the circuit in the illustration has impedance at frequency ω given by Eq. (3) and admittance given by Eq. (4),
so that the conductance, given by Eq. (5),