Temperature Measurements

            
             The purpose of this lab was to become familiar with the construction of temperature sensors and to test their behavior under steady-state conditions. Type-T thermocouples were built with a single junction and single reference junction. The thermocouple was built by the students and voltage readings were taken during varying water temperature.
             Conclusions:.
             This lab was a success in that the students did gain familiarity with the construction of temperature sensors as well as test their behavior under steady-state conditions. This lab also helped to prove the importance of a uniform and consistent sample in order to record an accurate measurement. Although we did not actually test the thermopile it is foreseeable how the extra reference and junction points can yield a more accurate and true reading. The lab also showed how a thermistor reflects a negative exponential curve with varying temperature and an RTD has a positive linear curve. Finally the lab proved the importance of the wires being protected from outside interference.
             Conduct of Experiment:.
             The lab was performed as written in the lab handout (Att. 1) with a few exceptions. The lab handout calls for three different types of thermocouples to be built and do to equipment malfunctions only the first thermocouple was able to be built. Do to the fact that only the first thermocouple was built; only tests with this thermocouple could be performed. .
             Results of Experiment:.
             Temperature [oC] Millivolts RTD [Ù] Thermistor [kÙ].
             13 0.52 105.9 15.9.
             30 1.12 112.6 7.55.
             40 1.63 116 4.76.
             50 2.04 120.9 3.13.
             60 2.42 124.9 2.067.
             70 2.99 128.9 1.54.
             80 3.48 132.7 1.09.
             90 4.001 136.7 0.788.
             91.5 3.938 137 0.766.
             The calibration for the thermistor giving the mean resistance as a function of thermometer reading and the best fit exponential equation as well as the manufacturer's data can be compared on the graph below.
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             Chart 1: Temperature vs. Thermistor.
             The calibration curve of the RTD giving the mean resistance as a function of thermometer readings and the best fit linear equation can be seen in chart 2 below.