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

摘要

A method of detecting a dry/wet state of a thermistor bead comprises the ste ps of: generating a current waveform that transitions between first and second current levels; conducting the current waveform through the thermistor bead; measuring a voltage waveform across the thermistor bead in response to the current waveform; measuring a slope of the voltage waveform in response to the first and second current levels and generating a first signal indicative of the measured slope; differentiating the voltage wavefor m to produce a voltage pulse representative of a transition of the voltage waveform from on e voltage potential to another and generating a second signal indicative of the polari ty of the voltage pulse; and detecting the dry/wet state of the thermistor bead based on the first and second signals. Apparatus for embodying this detection method is also disclosed.