Theory of Capacitive Proximity Sensors | How Capacitive Proximity Sensors Works? This knowledge of Sensors will help you better understand customer applications. In addition, you will be better able to describe products to customers and determine important differences between products. You should know Basics of Electricity and Basics of Control Components before attempting Sensors. Today we learn the Theory of Capacitive Proximity Sensors and how they work? Let’s Start. Capacitive proximity sensors are similar to inductive proximity sensors. The main difference between the two types is that capacitive proximity sensors produce an electrostatic field instead of an electromagnetic field . Capacitive proximity switches will sense metal as well as nonmetallic materials such as paper, glass, liquids, and cloth. The sensing surface of a capacitive sensor is formed by two concentrically shaped metal electrodes of an unwound capacitor. When an object nears the sensing surface it ente...