The Problem of Energy Balance in Electroacoustic Transducers

It is well known that reversible transducers (elektroakustische Wandler) may be represented as voltage-sources (M-representation) and as current-sources (N-representation). The relations bstween the transducer coefficients may be derived from the generalized Lagrange-equations, whereby one or the other representation appears according as the magnetic energy is combined with the kinetic and the electric with the potential (Poincare) or vice-versa. But they may also be derived by regarding the powers at input and output. In the case of the electrostatic transducer it is pointed out, that the coupling-two-port, which may be separated, possesses storing qualities at one of the representations. “Ideal transducers” as the transformer or the gyrator appear only if magnetic transducers are treated according to the M-representation and electric transducers according to the N-representation.