  We studied the effective electrical conductivity of dense random resistor
networks (RRNs) produced using a Voronoi tessellation when its seeds are
generated by means of a homogeneous Poisson point process in the
two-dimensional Euclidean space. Such RRNs are isotropic and in average
homogeneous, however, local fluctuations of the number of edges per unit area
are inevitably. These RRNs may mimic, e.g., crack-template-based transparent
conductive films. The RRNs were treated within a mean-field approach (MFA). We
found an analytical dependency of the effective electrical conductivity on the
number of conductive edges (resistors) per unit area, $n_\text{E}$. The
effective electrical conductivity is proportional to $\sqrt{n_\text{E}}$ when
$n_\text{E} \gg 1$.
