The word "Transducer" is the collective term used for both Sensors which can be used to sense a wide range of different energy forms such as movement, electrical signals, radiant energy, thermal or magnetic energy etc, and Actuators which can be used to switch 

or currents.

There are many different types of both analogue and digital input and output devices available to choose from. The type of input or output transducer being used, really d

epends upon the type of signal or process being "Sensed" or "Controlled" but we can define a transducer as a device that converts one physical quantity into another.

Devices which perform an "Input" function are com
monly called Sensors because they "sense" a physical change in some characteristic that changes in response to some excitation, for example heat or force and covert that into an electrical signal. Devices which perform an "Output" function are generally calledActuators and are used to control s