Abstract: An isolation region separates a first circuit region and a second circuit region. A signal conveyance element is an element to convey a signal from the first circuit region to the second circuit region and includes at least one primary coil and two secondary coils. The at least one primary coil has opposite ends electrically connected to the first circuit region and is disposed in the isolation region. The two secondary coils each have opposite ends electrically connected to the second circuit region, are arranged to be magnetically coupled to the at least one primary coil, and are arranged in the isolation region.

Abstract: A rotary tool is provided with a mode selecting part that selects one operating mode from a predetermined plurality of operating modes when a mode switching button is pressed. The plurality of operating modes include: a first auto stop mode where a motor rotates only for a first time period after an impacting operation is detected; and a second auto stop mode where the motor rotates only for a second time period which is shorter than the first time period after the impacting operation is detected.