a) for transduction of an electric signal into a mechanical signal, quotient of the resulting force in the blocked mechanical system by the excitation voltage in the electrical system;

b) for transduction of a mechanical signal into an electric signal, quotient of the resulting short-circuit current in the electrical system by the excitation velocity in the mechanical system

NOTE – These definitions are best applied to a reciprocal electromechanical transducer with transformer coupling, for example an electrostatic or piezoelectric transducer, in which case the two quotients have equal magnitude.