초록 ▼

A capacitive level sensor for sensing level of a in a vessel includes a sensor coupled to the vessel having a shield and an inner sensing rod. An oscillator provides an RF signal to the shield and the sensing rod. Comparison circuitry couples to the sensing rod provides a wet/dry output in response

A capacitive level sensor for sensing level of a in a vessel includes a sensor coupled to the vessel having a shield and an inner sensing rod. An oscillator provides an RF signal to the shield and the sensing rod. Comparison circuitry couples to the sensing rod provides a wet/dry output in response to capacitance between the inner sensing rod and the vessel, the capacitance related to the level of the liquid in the vessel.

대표청구항 ▼

[ What is claimed is:] [1.] A capacitive level sensor for sensing level of a liquid in a vessel, comprising:a sensor coupled to the vessel having a shield and an inner sensing rod, the inner sensing rod forming a capacitance with the vessel and wherein a coating can form on the sensor;an oscillator

[ What is claimed is:] [1.] A capacitive level sensor for sensing level of a liquid in a vessel, comprising:a sensor coupled to the vessel having a shield and an inner sensing rod, the inner sensing rod forming a capacitance with the vessel and wherein a coating can form on the sensor;an oscillator having an enable input and responsively providing an RF output to the shield and the sensing rod and thereby driving the capacitance formed between the rod and the vessel;a pulse source periodically providing an enable signal to the enable input of the oscillator to thereby reduce power consumption when a coating has formed on the sensor; andcomparison circuitry coupled to the rod providing a wet/dry output in response to the capacitance between the rod and the vessel due to the liquid.