Dictionary.net

an electrical device that converts one form of energy into another

an electrical device that converts one form of energy into another

Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photelectric cell, automobile horn, doorbell, and underwater soundtransducer. (MacGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)