Abstract
An instrument with which to produce sine and square wave changes in pressure in the hydraulic systems of membrane manometers is described. It consists of a cylindrical chamber to one end of which a metal membrane is secured; fixed to the membrane is a barium titanate strain gauge which, when energized by alternating voltages, causes alternating pressure changes in the chamber. The theory on which the construction of this instrument is based is substantiated by experiment. The use of the instrument in the examination of a damped capacitance manometer system is described.