Patent ID: 6530686
Filing Date: 2003-03-11
Classification: G01N

Abstract:
A differential scanning calorimeter, comprising: a heat sink formed of a thermally conductive material and having an internal space for accommodating a sample; a detector fixed within the heat sink and formed by an insulating substrate having formed thereon a plurality of symmetric circuit patterns of metal resistors; a temperature measuring circuit for measuring a temperature of the detector by detecting a resistance value of at least one of the metal resistors in the detector; a differential temperature detecting circuit for comparing resistance values of one pair of symmetric metal resistors to detect a temperature difference between a sample and a reference placed on the detector, each in proximity to a respective one of the one pair of symmetric metal resistors; a program temperature function generator for outputting temperature target values in a time sequential manner; a heat sink temperature controller for controlling a temperature of the heat sink depending on an output of the program temperature function generator; a detector temperature controller for controlling a temperature of the detector by controlling currents flowing through the metal resistors in the detector based on a comparison result of an output of the program temperature generator and an output of the temperature measuring circuit; a differential heat compensating circuit for causing a proper current to flow through one pair of symmetric metal resistors in the detector such that an output of the differential temperature detecting circuit is reduced toward zero; whereby a low drift characteristic and a high responsiveness are both obtained.