High- temperature system for continuous recording of internal friction and elastic modulus

A system centering around an instrument which comprises a self- excited generator with electromechanical transducers included in its feedback circuit was developed. The photoelectric converter consists of an illuminator, with bulb supplied with direct current, an FSD- 1 photoconductive cell, and a tab attached to the pendulum and blocking part of the light path. The radiant flux ismodulated by the tab as the pendulum bob oscillates, thus varying the current to the photoconductive cell, and thereby varying the voltage across the amplifier input. See also English translation in Ind Lab (USSR) v 37 n 10 Oct 1971 p 1608-10