A device for transforming or converting power from one form to another. Thus, a microphone is a transducer which converts variations of sound pressure into variations of electrical current, and a loudspeaker is a transducer which performs the reverse function. Such devices are termed electroacoustic.
See: Diaphragm. Compare: Amplifier, Generator, Limiter, Receiver, Rectification.
The equivalent device for changing audio signals to digital form and back is called a converter. See: Digital Recording, Sound Synthesis.
Another type of transducer is the accelerometer which reacts to the acceleration (rate of change of velocity) of a surface to which it is attached, producing an equivalent electrical signal.
The ear itself may be regarded as a complex non-linear transducer in that it converts acoustic energy into electrical impulses in the inner ear. See: Basilar Membrane.