| 摘要 |
1361704 Varistors GENERAL ELECTRIC CO 29 Sept 1972 [1 Oct 1971] 45037/72 Heading H1K A varistor assembly 10 (Fig. 3) comprises a metal oxide substrate 11 having opposed major surfaces 12, 13 andα>10 for current density 10<SP>-3</SP> to 10<SP>2</SP> A/cm<SP>2</SP> in the characteristic I = (V/(C)<SP>α</SP> where I current, V = voltage, and C is a constant. Electrodes 14, 15 ohmically contact surfaces 12, 13 and have attached leads 16, 17. High thermal conductivity spaced plates 19, 20 of, e.g. Cu parallel to the surfaces are bonded together by potting compound 18 enclosing the varistor substrate and its electrodes for heat dissipation, and the compound contains high thermal conductivity insulant material, e.g. boron nitride, beryllium nitride or oxide, aluminium nitride and an epoxy resin. The substrate material is polycrystalline material of, e.g. zinc oxide with a small proportion of bismuth, aluminium, iron, magnesium or calcium oxides sintered together and pressed into shape. One of the spaced plates may be drilled for mounting, and in a modification (Fig. 4, not shown) the leads may be planar extensions of the electrodes. |
