The paper describes experiments designed to measure capacitance change by the variation produced in the frequency or phase of a signal from an oscillator normally of high frequency-stability. The advantages of such a method are tabulated, and the factors limiting the sensitivity and stability noted. In the experiments the sensitivity was increased by a process of frequency multiplication and frequency changing. An initiating oscillator designed to reach a high frequency-Stability at one particular frequency of operation is described. The auto-synchronized oscillator was adopted as a frequency discriminator with a high sensitivity but with restricted linear operating range. Results are given which indicate that capacitance changes of 5#x00D7;10#x2212;4#x03BC;#x03BC;F were measurable with a possible error of #x00B1; 50. Simple experiments to study the method for possible use in the measurement of capacitance changes occurring in about one millisecond are described.
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