Sensors and transducers

Although the words ‘sensor’ and ‘transducer’ are often used as if they have the same meaning, their purpose is entirely different. A sensor is a device intended for detecting or measuring a physical quantity such as light, sound, pressure, temperature or magnetic field strength. It has an electrical output (often a varying potential or a current) which varies according to variations in the quantity it is detecting. A transducer is simply a device for converting one form of energy into another form of energy.

Some sensors are also transducers. For example, a crystal microphone (p. 118) converts the energy of sound waves into electrical potentials. It conveniently converts the sound energy into a form that can be handled ...

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