Medical transducers

An Introduction to Sensors and Transducers

=The words 'sensor' and 'transducer' are both widely used in the description of measurement systems

=The word 'sensor' is derived from entire meaning 'to perceive' and 'transducer' is from transducer meaning 'to lead across'.

=A dictionary definition of 'sensor' is `a device that detects a change in a physical stimulus and turns it into a signal which can be measured or recorded;
=A corresponding definition of 'transducer' is 'a device that transfers power from one system to another in the same or in the different form'. 
=A sensible distinction is to use 'sensor' for the sensing element itself and 'transducer' for the sensing element plus any associated circuitry. 
=All transducers would thus contain a sensor and most (though not all) sensors would also be transducers.