The current density $j_{\mathbf{B}}$ of a species B in a given point of the solution is obtained by multiplying the flux density of that species at the given point by the Faraday constant $F$ and by the charge number $z_{\text{B}}$ of the species: $$j_{\mathbf{B}}=z_{\text{B}}F{N}_{\mathbf{B}}$$ where $j_{\mathbf{B}}$ is a vector which indicates the direction in which the charges transported by the species B flow and which gives the number of these charges going through a plane oriented perpendicular to the vector, divided by time and by area, and $N_{\mathbf{B}}$ is the flux density of a minor constituent of the solution with respect to a fixed frame of reference.