Thermistors as Instruments of Thermometry and Anemometry

Abstract

Thermistor beads are used as the sensitive elements for measuring temperature and wind speed. Their high resistance makes it unnecessary to correct for the resistance of leads or the change in their resistance due to temperature. Because of the high negative temperature coefficient of resistance of thermistor material slight changes in ambient temperatures caused sufficient changes in the bead resistance to unbalance a bridge circuit and thereby activate a recording milliammeter which had been calibrated to read temperatures. The change in resistance of a hot bead by the wind activated a second milliammeter which was calibrated to read wind speed.