An electrical device comprises a positive electrode terminal for connection to the positive electrode of a battery, a negative electrode terminal for connection to the negative electrode of the battery, a load circuit receiving power from the positive and negative electrode terminals connected to the battery, a voltage detector detecting the voltage between the positive and negative electrode terminals, and a short circuiting portion for short-circuiting between the positive and negative electrode terminals when the voltage detected by the voltage detector becomes not larger than a particular preset voltage.