Patent ID: 6880397
Filing Date: 2005-04-19
Classification: G01F

Abstract:
1. A device for sensing a level of a fluid by means of a probe having an impedance across first and second outputs, wherein the impedance varies depending upon whether the probe is at least partially immersed in the fluid to be sensed or not so immersed; the device comprising: a capacitor connected in series with one output of the probe; means for applying a DC potential to the capacitor for a first period of time so that the voltage across the capacitor is a function of the probe impedance; means for measuring a voltage associated with the voltage across the capacitor after said first period of time, said measured voltage indicative of whether the probe is immersed or not immersed in said fluid; and means for at least partially discharging the capacitor after the means for measuring a voltage associated with the voltage across the capacitor has measured said voltage, wherein said means for at least partially discharging the capacitor does so by applying a second DC potential to the capacitor for a second period of time so as to minimize probe damage.