METHOD AND APPARATUS FOR DETECTING A DRY/WET STATE OF A THERMISTOR BEAD USING TEMPERATURE COMPENSATION

摘要

A method of detecting a dry/wet state of a thermistor bead comprises the ste ps of: conducting a bias current through the thermistor bead; measuring a voltage across the thermistor bead in response to the bias current; measuring a temperature in proximity to the thermistor bead; generating a reference voltage in proportion to the measure d temperature; and detecting the dry/wet state of the thermistor bead based on the measured and reference voltages. Also disclosed is apparatus for detecting a dry/wet state of a thermistor bead which comprises: a first circuit coupled to the thermistor bead for conducting a bias current through the thermistor bead; a temperature sensor for measuring a temperature in proximity to the thermistor bead; a second circuit coupled to the temperature sensor for generating a reference voltage in proportion to the measured temperature of the sensor; and a third circuit coupled to the thermistor bead for measuring a voltage across the thermistor bead in response to the bias current, and also coupled to the second circuit for detecting the dry/wet state of the thermistor bead based on the measured and reference voltages. Apparatus for implementin g this method is also disclosed.