Capacitive sensors contain an oscillator transistor in the front section. The oscillating circuit R-C (resistor-capacititor) is influenced by variations
in capacity in fact when any material, solid or liquid (water, wood, metals, coffee, powders, etc.) come into contact with the active surface
of the sensor the capacitance increases putting into action the oscillator up until the threshold of trigger inverts.
By introducing a change in the condition of the final stage and therefore in the command of the external load a potentiometer makes fine adjustements to the switching distance. All the sensors are protected against a change of polarity and electrical disturbances of inductive origin, and they are protected against short circuits.
