transducer

transducer device that accepts an input of energy in one form and produces an output of energy in some other form, with a known, fixed relationship between the input and output. One widely used class of transducers consists of devices that produce an electric output signal, e.g., microphones and photoelectric cells . Other widely used transducers accept an electric input, e.g., loudspeakers , light bulbs, and solenoids. The term transducer is sometimes applied to devices producing an output in the same form as their input, e.g., transformers and filters.

transducer
1. (sensor) Any device that converts energy in the form of sound, light, pressure, etc., into an equivalent electrical signal, or vice versa. For example, a semiconductor laser converts electrical energy into light, and a piezoelectric device converts mechanical stress into electrical energy (and vice versa).

2. In formal language theory, any automaton that produces output.

transducer Device for converting any nonelectrical signal, such as sound or light, into an electrical signal, and vice versa. Examples include microphones, loudspeakers, and various measuring instruments used in acoustics.