where σ is the electrical conductivity (SI unit: S/m), and
Je is an externally generated current density (SI unit: A/m
2). The static form of the equation of continuity then states:
In planar 2D the Electric Currents interface assumes that the model has a symmetry where the electric potential varies only in the x and
y directions and is constant in the
z direction. This implies that the electric field,
E, is tangential to the
xy-plane. The Electric Currents interface then solves the following equation, where
d is the thickness in the
z direction: