THE DESIGN, CONSTRUCTION, AND OPERATION OF A DIFFERENTIAL MICROMANOMETER. PART I. ELECTRONICS
Kenneth W. Lamers · eScholarship (California Digital Library) · 1964
Part I of this report covers the electronics of a micromanometer designed to measure pressure differentials on the order of 0.1 micron with an accuracy of 3o/o.The micromanometer is to be used in conjunction with a Wrede gauge, a device that converts atomic concentration into a pressure differential.The pressure difference is sensed by a membrane manometer constructed in the form of a differential capacitor that forms two legs of a resonant '-bridge network excited by a radio -frequency source.The bridge output (2. 7 me) is amplified and fed to a phase-sensitive detector that determines the direction of unbalance and develops a de voltage that restores the tnembrane essentially to its initial position.The restoring voltage is directly proportional to pressure differential and is indicated by a recorder.Micromanometers of this type are not new.What this report describes that has not been described before are: ( 1) details of frequency considerations;• and (2) selection of parameters that lead to increased bridge sensitivity.Electrical performance only is described in Part I of this report.Total performance and theory are described in Part II.