| 摘要 |
PROBLEM TO BE SOLVED: To ensure good switching characteristic exhibiting low electric resistance under conducting state and high electric resistance under nonconducting state by employing a structure where a bismuth metal wire or bismuth alloy wire causing volumetric contraction under molten state is encapsulated in an electric insulating substance. SOLUTION: The current switching element has a structure where a bismuth metal wire or bismuth alloy wire 2 causing volumetric contraction under molten state is encapsulated in an electric insulating substance 4, e.g. ceramics, glass or high polymer. When temperature of the element is increased, bismuth melts at the melting point (271 deg.C) or above and the wire 2 is broken at the drawing position 3 thereof cause abrupt increase of electric resistance. When temperature of the element is decreased, the molten bismuth expands and solidifies at a temperature about 20 deg.C lower than the melting point to cause decrease of electric resistance. Preferably, the diameter of the wire 2 is in the range of 10-1000μm and the diameter of the wire 3 subjected to drawing is in the range of 0.1-10μm.
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