Patent ID: 7416329

Claim:
A circuit indicating icing conditions, comprising: a bridge circuit comprising resistors and first and second sensor inputs coupled together in a bridge that provides bridge outputs; the first sensor input being couplable to a first electrically heated temperature sensor subject to heat removal by airflow from which liquid moisture has not been removed, and the second sensor input being couplable to a second electrically heated temperature sensor subject to heat removal by airflow from which liquid moisture has been removed; an electrical supply that supplies electrical power for heating both the first and second electrically heated temperature sensors; an ambient temperature sensor that provides ambient temperature data; and a computer coupled to the bridge outputs and the ambient temperature data, the computer providing an icing condition output based on bridge output data and ambient temperature data, the icing condition output indicative heat removal due to evaporation or blow-off of warmed water from the first electrically heated temperature sensor.