Piezo-Electric Resonance and Oscillatory Phenomena with Flexural Vibrations in Quartz Plates

A method of obtaining flexural vibrations from piezo-electric quartz plates together with the equations for flexural vibrations in quartz is given. Crystal mountings for obtaining best results with the first, second, and higher modes of flexural vibration are developed. The use of the crystal at flexural frequencies in the oscillator circuits of Cady and Pierce, and the luminous phenomena obtained when resonating in a partially evacuated chamber with different types of mountings, are also described. Without using unusually long plates the range of frequencies obtainable is extended into the audible range. Among the problems still to be solved are the temperature coefficient of frequency and logarithmic decrement for the various modes of flexural vibration as well as constancy of frequency under variations of load and constants of the electric circuit. Investigations are still in progress, of which a report will be communicated later.