This document discusses transducers and resistive transducers. It defines a transducer as a device that converts one form of energy into another, such as converting electrical energy to sound in a microphone. Transducers are used to measure physical quantities by converting them to electrical signals. Resistive transducers operate based on changing resistance and include potentiometers, resistive position sensors, pressure sensors, strain gauges, thermistors and light dependent resistors. Potentiometers specifically work by varying voltage levels through the motion of a sliding contact along a resistive element.