Modified Dauphinee Thermocouple Comparator Circuit for Adiabatic Calorimetry

Abstract

A modified Dauphinee thermocouple circuit has been used to isolate the thermocouples in the circuitry of an adiabatic calorimeter. The system eliminates direct electrical connection between thermocouples to be welded to a common ground. The variation in the difference in the emf between two thermocouples at the same temperature is less than ±0.2 μV. A calorimeter using the Dauphinee circuit has been used to determine specific heats of metals up to 700°C with a reproducibility, over a wide range of heating rates, of better than ±0.5%.