Electromechanical Transducer

a device for converting mechanical motion (vibrations) into variations of an electric current or voltage (electric signals) and vice versa. Electromechanical transducers are used primarily as actuating mechanisms in automatic control systems and as sensors of mechanical motion in automation and measurement technology. They may be classified according to the conversion principle used as resistive, electromagnetic, magnetoelectric, and electrostatic types; they may also be classified according to the type of output signal as analogue and digital types (with analogue and discrete output signals, respectively).

Electromechanical transducers are evaluated with respect to their static and dynamic characteristics, the sensitivity (or transfer ratio) E = Δy/Δx (where Δy is the change in the output quantity y when the input quantity x is changed by Δx), the operating frequency range of the output signal, the static error of the signal, and the static error of conversion. Examples of electromechanical transducers are the measuring mechanism of a permanent-magnet instrument, a loudspeaker, a microphone, and a piezoelectric transducer.