Disclosed is a control system for a heated conduit for use in a respiratory apparatus. The control system comprises a power supply (440), a heating control circuit, a sensing circuit (428) and a bias generator circuit. The power supply (440) provides power to the heated conduit. The heating control circuit is configured to control heating to obtain a predetermined temperature. The sensing circuit (428) is configured to indicate the temperature of a sensor (410) positioned in the heated conduit. The bias generator circuit is configured to provide a current to the sensor from a current source (642), 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.
