Patent ID: 8125307

Claim:
An aggregate substrate comprising: a first varistor part comprising a first varistor element layer to exhibit nonlinear voltage-current characteristics, and a plurality of first internal electrodes juxtaposed in an extending direction of the first varistor element layer in the first varistor element layer, said first varistor part having a first principal face and a second principal face facing each other; a second varistor part comprising a second varistor element layer to exhibit nonlinear voltage-current characteristics, and a plurality of second internal electrodes juxtaposed in an extending direction of the second varistor element layer in the second varistor element layer, said second varistor part having a third principal face and a fourth principal face facing each other; and a heat dissipation layer having a fifth principal face and a sixth principal face facing each other, wherein the fifth principal face of the heat dissipation layer is in contact with the second principal face of the first varistor part and wherein the sixth principal face of the heat dissipation layer is in contact with the fourth principal face of the second varistor part, wherein the first varistor part further comprises a plurality of pairs of first surface electrodes formed on the first principal face, wherein the second varistor part further comprises a plurality of pairs of second surface electrodes formed on the third principal face, wherein each of the first surface electrodes in each pair is opposed at least in part to the corresponding first internal electrode, and wherein each of the second surface electrodes in each pair is opposed at least in part to the corresponding second internal electrode.