A liquid microbarograph

A liquid microbarograph has been designed for continuous recording of variations in the atmospheric pressure with characteristic times ranging from 0.25 s to a few hours with a resolution of 0.02 Pa or better. The instrument is based on a sensor composed of two communicating vessels filled with transformer oil. A shift of the liquid level is recorded by the measuring circuit, the key component of which is an AD7746 capacitance-to-digital converter. The microbarograph has been used to good effect as a part of the atmospheric measuring system (Apatity, Murmansk oblast) over the last 3 years.