Patent ID: 6276202
Filing Date: 2001-08-21
Classification: G08B

Abstract:
Device for detecting snow and ice including a humidity sensor mounted in a peripheral environment for determining a humidity in a surrounding atmosphere subject to exposure by any of a snow precipitation, an ice formation and a water-vapor containing air with which a heating current circuit is associated, and an evaluation circuit controlled in dependence on a humidity sensor-measured variable, which produces a switching and/or control signal at predetermined humidity values, characterized in that an ambient temperature sensor is arranged in a control circuit which activates the humidity sensor when a temperature within a predetermined temperature range is detected; that the humidity sensor has a PTC (Positive Temperature Coefficient) resistance or heating element whose operating state with an electrical current consumption changes depending upon an ambient temperature change and an energy dissipation loss to said environment and atmosphere, which electrical current consumption is monitored by an electrical measuring current circuit and is used as an indicator of the humidity; and that the two sensors are mutually spaced within an elongate sensor cartridge such that the temperature sensor is thermally decoupled from the PTC heating element.