Differential 3 omega calorimeter

Abstract

We have developed a new dynamic calorimeter using the differential 3omega detection method. The differential 3omega calorimeter is capable of measuring dynamic heat capacity of liquid samples. The new calorimeter consists of a Wheatstone bridge made of two identical heater/sensors, and is based on the sensitive null detection method. The balancing is done automatically at all frequencies and is independent of temperature; once a sample is placed on one heater/sensor, a third harmonic signal is produced due to the difference in the two arms of the bridge. The differential 3omega calorimeter provides enhancements over traditional dynamic methods in dynamic range (up to 30 kHz), resolution, and ease of operation. (C) 2003 Elsevier Science B.V. All rights reserved.