Capacitive sensors work by measuring the dielectric of the material around the sensor. This dielectric value increases both when there is more material in front of the sensor and the closer that the material gets to the sensor. This means that capacitive sensors work differently than inductive proximity sensors. Capacitive sensors can detect virtually any material whereas inductive sensors are designed to sense only ferric materials. Capacitive sensors are indifferent to color and work with both liquids and solids.