Development of variable capacitance pressure transducers for vacuum applications

Abstract

The development of variable capacitance diaphragm-type pressure transducer systems for vacuum applications is described in detail. This technology area is an interesting and challenging problem of design and manufacturing engineering and incorporates an interdisciplinary mixture of material science, and state-of-the-art techniques in electronics. Since the measurement system must be usable for a wide variety of applications in vacuum science ranging from very high accuracy metrology transfer standards to general-purpose vacuum measurements under very demanding environmental conditions, many conflicting factors must be considered in the design. For all practical purposes, this technology has evolved over a 35 yr period from 1949 to 1984 within which there have been several distinct developmental time periods; 1949–1969, 1970–1975, 1975–1980, 1981–1984. This paper will review the technology, considering the chronological development of sensors, signal conditioners, and overall transducer systems. Some very recent advances will be discussed as well as projections for the future.