Transducers and sensors have close relationship each other. The definition of transducers and sensors is described as follow:
The transducer is a device that converts energy from one form to another. Transducers can be divided into two classes, namely input transducers and output transducers. Input transducers convert non-electrical energy, such as sound or light into electricity. Electrical output transducers working in the opposite order. The transducers convert electrical energy in the form of non-electric energy.
Sensors are devices used to detect and often serves to measure the magnitude of something. The sensor is a type of transducer used to convert variations in mechanical, magnetic, heat, light, and chemistry into voltage and electric current. Sensors are usually categorized by the measuring and has important role in modern manufacturing process. The sensors provide equivalent eye, hearing, nose, tongue to be microprocessor brain of industrial automation systems.