ABSTRACT
Figure3.1isaschematicofthedifferentialthermalanalyzer (DTA)design.Thedevicemeasuresthedifferenceintemperaturebetweenasampleandreferencewhichareexposedto thesameheatingscheduleviasymmetricplacementwithrespecttothefurnace.Thereferencematerialisanysubstance, withaboutthesamethermalmassasthesample,whichundergoesnotransformationsinthetemperaturerangeofinterest. Thetemperaturedifferencebetweensampleandreferenceis measuredbya"differential"thermocoupleinwhichonejunctionisincontactwiththeundersideofthesamplecrucible, andtheotherisincontactwiththeundersideofthereferencecrucible.1Thesampletemperatureismeasuredviathe voltageacrosstheappropriatescrewterminals(Vr.)andsimilarlyforthereferencetemperature(VrJ;generallyonlyoneor theotherisrecorded(seesection3.5.1).Sampleandreference
temperature measurements require cold junction temperature correction.
