Energetical aspects in transducers operation and classification, with emphasis on electrical measurement of mechanical quantities

Several ways in which the energy transfer is involved in the operation of electromechanical transducers are examined. Among the SI quantities, classes of intensive and extensive quantities may be distinguished, pairs of them forming together parameters having the dimension of an energy. Another interesting classification is in terms of the degree with which they appear in the fundamental equations of Physics, characterizing active and passive systems. Such systems are frequently found in the structure of force transducers. As a representative category of electromechanical devices, force transducers are deeply analyzed, their classification is commented and a few significant examples based on strain gauges are presented.