The present invention relates to a control system for a heated conduit for use in a respiratory apparatus. The control system comprises a power supply to provide power to the heated conduit. Additionally, it comprises a heating control circuit configured to control heating to obtain a predetermined temperature and a sensing circuit configured to indicate the temperature of a sensor positioned in the heated conduit as well as a bias generator circuit configured to provide a current to the sensor from a current source such that a voltage drop through the sensor may be recorded by the sensing circuit so that the temperature of the heated conduit is continuously monitored independent of whether the heating control circuit is on or off.
