A LOW COST AUTOMATIC SYSTEM FOR ANELASTIC RELAXATIONS MEASUREMENTS

A modified system for automatic collection of data of internal friction and frequency is devised utilizing an inverted torsion pendulum. This system is based on velocity method instead of traditional method of amplitude decrease of free vibrations. The time intervals are obtained through the reflection of a He-Ne laser beam, traversing two photodiodes separated by a known distance. An interface was developed which receives a signal of these photodiodes, amplified and takes it to a clock. The temperature is obtained by a digital multimeter and through a GP-IB type interface. A computer program was devised which reads simultaneously temperature, internal friction and frequency. We are also presenting some spectra obtained in our laboratory for metallic materials using the constructed system