To solve the problem wherein no function of preventing the short-circuit between a positive terminal and a negative terminal (called the ground) is provided for an electrical apparatus that requires a DC current in a general electrical apparatus.

The occurrence of failures can be reduced, by using a circuit that prevents troubles where the temporary loss of potential difference, which is caused by the physical contact of the positive terminal with the negative one (called the ground) or electrically, leads to a failure of a DC power supply circuit that supplies a DC to the electrical apparatus, when a DC is supplied in using general electrical apparatus.