Thermistor based ultra-sensitive thermal probe and its signal processing methods suitable for solution calorimeter

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  • R. parthasarathy IndiraGandhi Centre for Atomic Research Kalpakkam
  • K. H. Mahendran
  • S. Premalatha

Klíčová slova:

Thermistor, lock in amplifier, integrating type ADC, solution calorimeter, Dewar Vessel

Abstrakt

 A sensitive thermometric probe to measure a minute change in temperature of the order of mK, is designed and developed as a prerequisite for the in-house development of solution calorimetry system to study the heat of solutions of the compounds containing alkali metals. A measurement range of 2 K is considered in commensurate with the volume of the solution and the sample size. In this paper, construction of the probe using a thermistor, a linear signal-conditioning scheme, and calibration procedure using the PT100 are discussed. The inexpensive electronics scheme with a lock-in-amplifier and an integrating type ADC is prudently adapted for measuring a change of thermistor resistance of the order 0.1 W in 10,000 W. An adaptive procedure of the signal conditioning scheme to measure temperature over a wider range and also at a suitable base temperature is also discussed. The versatile measurement technique realizes a measurement of minimum change in temperature 2.127 x10–4 oC over the base temperature of 25 oC. The probe is successfully adapted in out solution calorimetry system as well. Keywords: Thermistor, lock in amplifier, integrating type ADC, solution calorimeter, Dewar Vessel 

Biografie autora

  • R. parthasarathy, IndiraGandhi Centre for Atomic Research Kalpakkam
    Chemical Facilities DivisionHead, Chemical Instruments Section

Stažení

Publikováno

2012-09-23

Číslo

Vol 2 No 2 (2012)

Sekce

Research Articles

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