A varistor may include a varistor ceramic that includes zinc oxide having a molar percent greater than 90 percent and a set of metal oxides, where the set of metal oxides includes Bi2O3 having a molar fraction between 0.2 and 2.5 percent; Co3O4 having a molar fraction between 0.2 and 1.2 percent; Mn3O4 having a molar fraction between 0.05 and 0.5 percent; Cr2O3 having a molar fraction between 0.05 and 0.5 percent; NiO having a molar fraction between 0.5 and 1.5 percent; Sb2O3 oxide having a molar fraction between 0.05 and 1.5 percent; B2O3 having a molar fraction between 0.001 to 0.03 percent; and aluminum in the form of an oxide having a molar fraction between 0.001 and 0.05 percent.