The invention concerns an antimicrobial peptide, called myticin, characterised in that it can be obtained from a bivalve mollusc shellfish, and its molecular mass is about 4. The rotor 13 includes first and second magnetic members 21, 23 for forming at least one magnetic flux loop 19 and the first and second magnetic members 21, 23 are made of materials different from each other. The gear speed reducing mechanism is furnished with an angular positioning part that is a stopper part or an engaging region for controlling the rotation of the output shaft in a prescribed angle. In one example the force transducer uses a piezoelectric film for sensing. Further, feedback to the linear regulator taken from the combined output signal causes it to generate anti-phase ripple compensation, thereby reducing the magnitude of switching ripple in the converter’s combined output signal.