Method of generating signal in dependence on liquid film on surface and apparatus for making the same

摘要

In order to determine the thickness of a water film on a surface, especially on a street, a portion of the water film is heated or cooled and the thickness of the water film is determined from the march of temperature during heating or cooling. A generated output signal is used to determine a range from many possible ranges in which the thickness of the water film lies. A Peltier element (1) is used for heating the water film. The temperature of the water film is measured by a thermoelement (5) and is evaluated by a microprocessor (8).