To prevent damages from expanding due to smoking and ignition of an electrical component itself at increase of internal loss in the component, and to prevent device troubles caused by continuous use of a capacitor where failures have occurred.

The capacitor is provided with a switch which is electrically connected parallel to the capacitor and is formed by holding a thermoplastic piece between pins constituted of two opposed metals with spring properties. The thermoplastic piece melts due to the heat generation of the capacitor and brings the pin into contact with the switch part, thus short-circuiting it electrically. Consequently, the overcurrent protective function of a power supply is activated, and heat generation of the capacitor is reduced.