Absolute measurements of thermal effusivity using the electropyroelectric technique

Abstract

The so-called electropyroelectric technique uses amplitude modulated electrical current as excitation source of thermal waves in a pyroelectric sensor in contact with a liquid sample. Here it is showed that this technique allows absolute measurements of the thermal effusivity using the quotient of the signal amplitudes obtained from the inverse and the direct configurations. In this way the influence on the experimental results of the frequency dependent instrumental transfer function can be straightforwardly eliminated. Measurements performed in various test liquid samples are presented that demonstrate the good accuracy and usefulness of the method.