With certain technical applications actuation has to be carried out at positions where the required energy supply is costly or difficult to provide. The methods typically proceed stereospecifically, in high yield, do not require the use of activated intermediates andor toxic compounds and are readily amenable to scale-up. Three locking systems are provided. The sensing plate and sensor substrate are arranged in one of a substantially parallel planar or coplanar relationship with respect to one another, and the connection plate, diaphragm, sensing plate and piezoelectric element define a resonance portion. A feedback connector is provided for feeding back a feedback signal representative of the load current to circuitry for outputting a gate driver voltage supply control signal based on at least reference level and the feedback signal. The chassis defines a number of side openings on the side surface from the grasp portion surface and along a direction parallel to the axis of the chassis.