Capacitance sensors are devices that measure changes in capacitance, which is the ability of a system to store an electric charge. These sensors typically consist of two conductive plates separated by an insulating material. When an object comes close to the sensor, it alters the electric field between the plates, resulting in a change in capacitance that can be measured and interpreted. These sensors are commonly used in various applications, including touchscreens, proximity sensors, and level sensing in liquids. They are valued for their sensitivity and ability to detect non-metallic materials, making them versatile in industrial and consumer electronics.