Consider an electrical network modeled by a digraph G each directed edge e of which is a semiconductor with a monomial conductance function ye∗=fe(ye)=yes/μer if ye≥0 and ye∗=0 if ye<0. Here ye is the potential difference (voltage), ye∗≥0 is the current in e, and μe>0 is the resistance of e; furthermore, r>0 and s>0 are two real parameters common for all edges. In particular, case r=s=1 corresponds to the Ohm law, while r=12,s=1 may be interpreted as the square law of resistance, which is typical of hydraulics and gas dynamics. We show that for every ordered pair of nodes a,b of the network, the effective resistance μa,b is well-defined. In other words, any two-pole network with poles a and b can be effectively replaced by two oppositely directed edges: from a to b of resistance μa,b and from b to a of resistance μb,a. Furthermore, for every three nodes a,b,c the inequality μa,cs/r+μc,bs/r≥μa,bs/r holds, in which the equality is achieved if and only if every directed path from a to b in G contains c. In addition to case (i) s=r=1, some limit values of parameters s and r are also of interest being related to classic triangle inequalities. Namely, (ii) the length/time of a shortest directed path, (iii) the inverse width of a bottleneck path, (iv) the inverse capacity (maximum flow per unit time) from a terminal a to a terminal b correspond to: (ii) r=s→∞, (iii) r=1,s→∞, (iv) r→0,s=1, respectively. These results generalize ones obtained in 1987 for monomial isotropic networks, which are modeled by undirected graphs. In this special case, effective resistances form a metric space when s≥r and an ultrametric one when s/r→∞. Of course, for anisotropic networks, which are modeled by directed graphs, the symmetry μa,b=μb,a may fail. For the linear isotropic networks triangle inequality is known since 1967 and it was extended to the linear anisotropic case in 2016.