A semiconductor device includes a semiconductor substrate, a first p-channel laterally diffused metal oxide semiconductor transistor formed over the semiconductor substrate and additional p-channel LDMOS transistors formed over the semiconductor substrate. The demand data memory stores plural power demand patterns and power demand amount data. The flow velocity measuring unit obtains a flow velocity of fluid based on time variation of a signal intensity depending on the inversion times at each of plural positions and a distance between the plural positions. The torque limiter has a breakable portion. Other embodiments are disclosed.