The Ultrasonic Interferometer with Resonant Liquid Column

The ultrasonic interferometer is simple in construction and operation, and yields accurate and consistent data. From these data, one can readily determine the velocity of sound in a liquid with high accuracy. Formerly, the absorption of sound in the liquid and the coefficient of reflection at the reflector surface has been obtained through a complicated analysis of the electrical and equivalent-electrical circuits of the quartz crystal and the associated fluid column. The simplified analysis of the equivalent circuit given here is made possible by limiting the discussion to the conditions that exist when all parts of the system (electrical, mechanical, and acoustical) are adjusted to resonance. Under these conditions, the analysis of the complete electrical and equivalent-electrical circuit is greatly simplified. One does not need to analyze the shape of a reaction dip in order to obtain coefficients of absorption and reflection.