Inductive Sensors are a non contact device specifically designed to detect metal objects. Traditionally used in the automotive and machine tools industry this type of sensor can detect a metal target through the likes of liquids and powders.
Capacitive Sensors are a non contact device similar to an inductive sensor but is able to detect all types of materials rather than just metal. They are traditionally used in such applications as level control of granules and powders in silos or hoppers.