Sensors are critical components in all measurement and control systems. The need for sensors that generate an

electronic signal closely followed the advent of the microprocessor and computers. Together with the ever-

present need for sensors in science and medicine, the demand for sensors in automated manufacturing and

environmental monitoring is rapidly growing. In addition, small, inexpensive sensors are finding their way

into all sorts of consumer products, from children’s toys to dishwashers to automobiles. Because of the vast

variety of useful things to be sensed and sensor applications, sensor engineering is a multidisciplinary and

interdisciplinary field of endeavor. This chapter introduces some basic definitions, concepts, and features of

sensors, and illustrates them with several examples. The reader is directed to the references and the sources

listed under Further Information for more details and examples.