A ceramic material comprising:(a) between about 50 and about 80 v/o of an electrically insulating ceramic having a resistivity of at least about 10 E+10 ohm-cm;(b) between about 10 and about 45 v/o of a semiconductive material having a resistivity of between about 1 and about 10 E+8 ohm-cm;(c) between about 5 and about 25 v/o of a metallic conductor having a resistivity of less than about 10 E-2 ohm-cm; and(d) between about 0.5 and about 20 v/o of a resistivity-enhancing compound selected from the group consisting of metallic oxides, metallic oxynitrides, rare earth oxides, rare earth oxynitrides, and mixtures thereof.