Editing Series and parallel circuits (section)

==== Conductance ====
[[Electrical conductance]] presents a reciprocal quantity to resistance. Total conductance of a series circuits of pure resistances, therefore, can be calculated from the following expression:
<math display="block">G = \left(\sum_{i=1}^n{1\over G_i}\right)^{-1} = \left({1\over G_1} + {1\over G_2} + {1\over G_3} + \dots + {1\over G_n}\right)^{-1}.</math>

For a special case of two conductances in series, the total conductance is equal to:
<math display="block">G = \frac{G_1 G_2}{G_1 + G_2}.</math>