Patent ID: 7541910

Claim:
A multilayer zinc oxide varistor with controllable breakdown voltages comprising a ceramic base body, internal electrodes and terminal electrodes, wherein the ceramic base body has a composition of bismuth-free and Pb—B—Zn—Si glass-free ZnO based metal oxide varistor containing 80˜99.5 mole % of zinc oxide as a main component, and 0.01˜10 mole % of BaO or BaCO 3 as first additive, 0.005˜10 mole % of Co 2 O 3 , MnO 2 , Cr 2 O 3 or NiO as second additives, 0.005˜10 mole % of Pr 2 O 3 , La 2 O 3 , Ce 2 O 3 , Nd 2 O 3 or Tb 2 O 3 as third additives, and 0.001˜5 mole % of B 2 O 3 , SiO 2 , SeO 2 , Al 2 O 3 , TiO 2 , WO 3 , SnO 2 , Sb 2 O 3 , Na 2 O or K 2 O as fourth additives.