What is Transducer? How Transducer Works? How Thermometer Works?

Transducers are the mechanical, electrical, electronic, or electromechanical devices that convert one form of the energy or the property that cannot be measured directly into the other energy or property that can be measured easily. The transducer selected for the measuring system is such that the output obtained is proportional to the input. Since the output can be measured easily by the available instruments, the scale can be calibrated between the values of the output and the input. This article describes what are transducers used in the measurement systems. It also describes working of one of the most common transducing devise: thermometer.