Electronics/Electro-Mechanical Analogies

Introduction

The goal of electro-mechanical analogies is to integrate electrical and mechanical components in a simple graphical way that illustrates the behavior of the system. Of course, one needs to be familiar with simple lumped electrical systems to appreciate the analogy. This is warranted because these circuits and procedures are still used in the transducer industry to model shakers, speakers, dynamic microphones, and other systems.

The two analogies between electrical and mechanical systems are the impedance analogy and the mobility analogy.

                      Mechanical           Electrical Equivalent
Impedance Analog
  potential            Force      $F(t)$        Voltage    $V(t)$
  flux                 Velocity   $u(t)$        Current    $i(t)$

Mobility Analog
  potential            Velocity   $u(t)$        Voltage    $V(t)$
  flux                 Force      $F(t)$        Current    $i(t)$

The impedance analog is often easier for most acoustical systems while the mobility analog more "naturally" represents mechanical systems. It also may be easier to draw one analog or the other in some cases.

Electro-mechanical Equivalent Components

1) The Equivalent Spring

2) The Equivalent Mass

3) The Equivalent Resistance