Overvoltage protection device including wafer of varistor material

摘要

An overvoltage protection device includes a first electrode member having a first substantially planar contact surface and a second electrode member having a second substantially planar contact surface facing the first contact surface. A wafer formed of varistor material and having first and second opposed, substantially planar wafer surfaces is positioned between the first and second contact surfaces with the first and second wafer surfaces engaging the first and second contact surfaces, respectively. The contact surfaces may apply a load to the wafer surfaces. Preferably, the electrode members have a combined thermal mass which is substantially greater than a thermal mass of the wafer. The wafer may be formed by slicing a rod of varistor material. The device may include a housing including the first substantially planar contact surface and a sidewall, the housing defining a cavity within which the second electrode is disposed.