I. The Measurement of Small, Commercial-Frequency, Alternating Potentials. II. The Normal Frequencies of Vibration for Systems of Point Particles Having Tetrahedral and Octahedral Symmetry

Citation

Steffens, Carsten Conover (1934) I. The Measurement of Small, Commercial-Frequency, Alternating Potentials. II. The Normal Frequencies of Vibration for Systems of Point Particles Having Tetrahedral and Octahedral Symmetry. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/8bqt-cz98. https://resolver.caltech.edu/CaltechTHESIS:12132024-234623984

Abstract

A mechanical rectifier for use at commercial frequencies has been constructed. Accidental electromotive forces have been so far eliminated that it can be used with a sensitive direct current galvanometer as a detecting instrument. Four galvanometers have been tried and the results are described. With the most sensitive galvanometers used, the sensitivities of the system at 50 cycles were 0.05 microvolts (without the critical damping resistance) and 0.00004 microamperes.

The use of a vibration galvanometer and of the mechanical rectifier with a low-frequency vacuum-tube amplifier has been investigated. An input potential 0.001 of that corresponding to the noise level of the amplifier can be detected. This combination is then about 100 times as sensitive as an amplifier with the same noise level used with a telephone receiver.

Thesis Files