Abstract: A piezoelectrical transducer for providing an altimeter with vibratory motion to attenuate the effect of static friction on the movement of a gear train responding to an altitude responsive aneroid.

Abstract: A quadrupole mass spectrometer gain control system for continually analyzing a gas mixture with accuracy. A quadrupole mass filter is located in the system to receive the gas mixture output from an ionization source. The quadrupole mass filter is operated in such a manner as to sequentially select the mass channel, detect mass peak amplitudes, and compensate for mass dependencies of individual channels through which an output signal representative of the percentages of an individual gas in the mixture is transmitted to a display. To compensate for system gain variations occurring in the ionization source, mass filter, ion detector, and detector preamplification function, a system gain control is provided in which the sum of the constituent gas amplitudes is compared with a 100% amplitude reference, and the error signal used to control the system gain.