${\displaystyle C=\frac{q}{u_{\mathrm{AB}}}}$

where the sign of the electric charge is determined by taking the electric current in the time integral defining this charge as positive if its direction is from A to B and negative if its direction is from B to A

Note 1 to entry: A capacitance cannot be negative.

Note 2 to entry: The coherent SI unit of capacitance is farad, F.