A solution calorimeter and thermistor bridge for undergraduate laboratories

1981 ◽  
Vol 58 (9) ◽  
pp. 732
Author(s):  
R. A. Bailey
Keyword(s):  
Thermistor Bridge ◽  
Solution Calorimeter

Modification of a Solution Calorimeter for Thermometric Titrations

1972 ◽  
Vol 4 (3) ◽  
pp. 189-195
Author(s):  
A. D. Wilks ◽  
M. D. Grieser ◽  
D. J. Pietrzyk
Keyword(s):  
Solution Calorimeter

A Digital Actinometer Utilizing a Thermistor Bridge Circuit

1970 ◽  
Vol 41 (8) ◽  
pp. 1231-1232
Author(s):  
Robert R. Birge ◽  
Donald C. Johnson
Keyword(s):  
Bridge Circuit ◽  
Thermistor Bridge

A Low-Noise Thermistor Bridge for Use in Calorimetry

1974 ◽  
Vol 20 (8) ◽  
pp. 1009-1012 ◽  
Author(s):  
Robert L Berger ◽  
Walter S Friauf ◽  
Horace E Cascio
Keyword(s):  
High Speed ◽  
Platinum Resistance Thermometer ◽  
Low Noise ◽  
Platinum Resistance ◽  
Resistance Thermometer ◽  
Thermistor Bridge ◽  
Flow Calorimeter ◽  
Titration Calorimeter ◽  
Lock In

Abstract A precision thermistor bridge and thermistor is described for use in a thermal titration calorimeter or a high-speed stopped- or continuous-flow calorimeter of the Roughton type. These are compared and evaluated with regard to several other types of detectors, including the platinum resistance thermometer, thermocouple, transistor thermometer, and capacitance thermometers. At this time the best detection for our purpose seems to be a specially constructed 20-100 kΩ thermistor used in conjunction with a new ac lock-in amplifier bridge. The sensitivity of the system is equivalent to a peak-to-peak noise of 25 x 10-6 °C, with a 100-ms time constant and 1 µW power dissipation in the thermistor. Long-term drift of the bridge, without an oven, was 1 x 10-6 °C/min.

Thermodynamics of ionization of aqueous toluidinium ions

1968 ◽  
Vol 46 (12) ◽  
pp. 1965-1967 ◽  
Author(s):  
W. F. O'Hara
Keyword(s):  
Free Energy ◽  
High Precision ◽  
Linear Relation ◽  
Solution Calorimeter ◽  
Thermodynamics Of Ionization

Standard heats of ionization of ortho-, meta-, and para-toluidinium ions in water at 25 °C have been determined in a high precision solution calorimeter. Entropies of ionization have been calculated from these heats and well-defined free energy changes. As predicted by theory, a linear relation is found between ΔS0Ion and ΔG0Ion and between ΔH0Ion and ΔS0Ion for these compounds.

A thermistor bridge using light-emitting diodes

1973 ◽  
Vol 50 (10) ◽  
pp. 684 ◽  
Author(s):  
A. M. Ferguson ◽  
L. F. Phillips
Keyword(s):  
Light Emitting Diodes ◽  
Thermistor Bridge ◽  
Light Emitting

An Inexpensive Solution Calorimeter

2008 ◽  
Vol 85 (8) ◽  
pp. 1129 ◽  
Author(s):  
Emma Kavanagh ◽  
Sam Mindel ◽  
Giles Robertson ◽  
D. E. Peter Hughes
Keyword(s):  
Solution Calorimeter

EBULLIOMETRY AND THE DETERMINATION OF THE MOLECULAR WEIGHTS OF POLYMERS: PART III. CONSIDERATIONS ON THERMISTOR WHEATSTONE BRIDGES

1959 ◽  
Vol 37 (12) ◽  
pp. 1365-1373 ◽  
Author(s):  
W. R. Blackmore
Keyword(s):  
Atmospheric Pressure ◽  
Background Noise ◽  
Wheatstone Bridge ◽  
Thermistor Bridge ◽  
Molecular Weights ◽  
Boiling Points ◽  
Pure Solvent ◽  
Unbalance Voltage

It is shown that a d-c. thermistor Wheatstone bridge may be used in ebulliometry to measure the small temperature differences which are observed between the boiling points of polymer solutions and the pure solvent. A relationship is derived between the thermistor bridge unbalance voltage and the solute molecular weight, which it is desired to measure. It is shown that a bridge composed of suitably matched thermistors may be made independent of the gross changes in boiling point of both solution and solvent produced by changes in atmospheric pressure. The possibility of the current flowing through the thermistors disturbing the measurements is discussed and in situ measurements of thermistor dissipation and time constants are given. The sensitivity attainable with various thermistor bridges and modern amplifiers at full gain is calculated and shown to be much greater than may be employed with the usual type of ebulliometer. The reason for this is the relatively large background noise (random temperature fluctuations) produced in the ebulliometer by the boiling process itself.

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