US Patent 9983042 Apparatus for detecting liquid level

An embodiment of the invention provides a liquid-level sensor to detect liquid-level information of a liquid to be tested in a container. The sensor includes an electrode, a sensing circuit, an amplifier and a controller. The electrode is disposed on the outer surface of the container, comprising a first electrode and a second electrode. The sensing circuit is coupled to a first electrode and a second electrode, and receives a clock signal to generate a first voltage signal and a second voltage signal. The amplifier receives the first voltage signal and the second voltage signal to output an output voltage. The controller acquires liquid-level information of the liquid to be tested according to the output voltage and a voltage-volume table.