Equivalent circuit representation of electromechanical transducers .1. Lumped-parameter systems

Lumped-parameter electromechanical transducers are examined theoretically with special regard to their dynamic electromechanical behaviour and equivalent circuits used to represent them. The circuits are developed starting from basic electromechanical transduction principles and the electrical and mechanical equations of equilibrium. Within the limits of the assumptions on boundary conditions, the theory presented is exact with no restrictions other than linearity. Elementary electrostatic, electromagnetic, and electrodynamic transducers are used to illustrate the basic theory. Exemplary devices include electro-acoustic receivers (e.g., a microphone) and actuators (e.g., a loudspeaker), electromechanical filters, vibration sensors, devices employing feedback, and force and displacement sensors. This paper forms part I of a set of two papers. Part II extends the theory and deals with distributed-parameter systems.