Varistor fitted with degradation alarm

摘要

A varistor provided with a degradation alarm function includes a first resistance element, an indicating element coupled in series with the first resistance element, a first thermal fuse coupled in parallel with a pair of the first resistance element and the indicating element, a varistor element coupled in parallel with the first thermal fuse, and a second resistance element disposed in an interconnect line between the first thermal fuse and the varistor element. A fusing temperature of the first thermal fuse is set such that the fuse is blown out at temperatures not lower than a temperature increased by heating when a current larger by a certain value than the maximum current rating of the varistor element passes through the fuse. The second resistance element is larger in resistance than the first resistance element.

主权项

1. A varistor provided with a degradation alarm function the varistor comprising:
a first resistance element; an indicating element coupled in series with the first resistance element; a first thermal fuse coupled in parallel with a pair of the first resistance element and the indicating element; a varistor element coupled in parallel with the first thermal fuse; and a second resistance element disposed in an interconnect line between the first thermal fuse and the varistor element, wherein a fusing temperature of the first thermal fuse is set such that the fuse is blown out at temperatures not lower than a temperature increased by heating when a current larger by a certain value than a maximum current rating of the varistor element passes through the fuse; and the second resistance element is larger in resistance than the first resistance element.