Electromechanic and Electroacoustic Transduction

Abstract

In the preceding chapter, we dealt with simple linear, time-invariant mechanic and acoustic networks and their electric analogies. In general, these networks can be quite complicated and may assume any number of degrees of freedom. Yet, regardless of how sophisticated the networks are, the energy and power transported in these networks is either mechanic, acoustic, or electromagnetic. Acoustic power and energy are of mechanic nature. Thus the terminological distinction between mechanical, $\underline{F}$, $\underline{v}$, and acoustical coordinates, $\underline{p}$, $\underline{q}$, is purely operational. In this chapter, we shall present the possibility of coupling electrical and mechanical domains, which results in a coupling of electric and mechanic energy and power. This topic is extremely important for modern acoustics.

This coupling can be manifold. The coupling element, the electromechanic coupler, can contain its own power sources and may be either active or passive. The relationship between mechanic/acoustic and electric coordinates can be linear or nonlinear. Coupling may be bi-directional, that is, exist for both directions, electric to mechanic and vice versa, or only mono-directional. It may be retroactive or not.