CAPACITOR EMBEDDED IN SAFETY DEVICE

PROBLEM TO BE SOLVED: To secure insulation of a conductive portion, by cutting a protective substrate in a safety device which is activated by detecting the deformation of a case. SOLUTION: A capacitor comprises a hermetic seal 4, a couple of mounting hardwares 5 and 6 which are mounted at opposite sides of the internal wall of the hermetic seal 4; a protective substrate 24 which is provided with a conductive portion 3 connected with a capacitor element and external connecting terminals at the middle portion where a defective portion 2 of an insulating substrate 1 is formed and is supported at its both ends by the mounting hardwares 5 and 6, under a condition where the protective substrate 24 is movable relative to at least one mounting hardware 6; an elastic body which is provided between the protective substrate 24 and the mounting hardware 6 which is movable relative to the protective substrate 24, and has tension so that the part of the protective substrate 24 which has moved relative to the mounting hardware 6 is pulled to the mounting hardware 6 side when the protective substrate 24 is cut at the defective portion 2, under a condition where the displacement of the hermetic seal 4 has moved the protective substrate 24 relative to the mounting hardware 6. This allows the insulation distance between the conductive portions 3 of the separate protective substrates 24 to be secured.