MENG 317 Measurement & Analysis Lab
Fall 2023
Lab 1
Measurement of Temperature using J-Type Thermocouple
Instructor: Dr. Mohammad Kamal Hossain
MENG 0317-01 Measurement & Analysis Lab
Tuskegee University
Department of Mechanical Engineering
Camille White
09/14/2023
Table of Contents
Abstract ……………………………………………………………………………………… 3
Introduction ………………………………………………………………………………….. 4
Experimental Procedures ………………………………………………………………. …… 5
Results ……………………………………………………………………………………….. 6
Discussion …………………………………………………………………………………… 9
Conclusion …………………………………………………………………………………... 10
References ……………………………………………………………………………………10
Appendix…………………………………………………………………………………….. 11
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Abstract
Temperature measurement using J-type thermocouples is a widely employed technique
known for its accuracy and versatility. This method relies on the thermoelectric effect exhibited
by two metal wires that generate a voltage proportional to temperature changes. This lab helps to
summarize the key aspects of J-type thermocouple-based temperature measurement, highlighting
its suitability for a broad temperature range, from cryogenic to elevated temperatures. In the lab,
students experimented with a pair of J-type thermocouples to gauge the temperature of water
reaching its boiling point. The student then determined both the experimental and theoretical
voltage levels corresponding to different temperatures. Following this voltage determination, the
students computed the percentage deviation in their measurements.
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Introduction
The purpose of measuring temperature using a J-type thermocouple is to obtain accurate
and reliable temperature readings over a wide range of temperatures. J-type thermocouples are
commonly used in various industries and applications due to their specific characteristics and
advantages, such as their durability, versatility, and cost-effectiveness make them a popular
choice for temperature measurement in diverse settings. J-type thermocouples are employed to
accurately and reliably measure temperature across a wide range of applications, ensuring
temperature control, process monitoring, and product quality in various industries and scientific
endeavors. The voltage generated by the J-type thermocouple is proportional to the temperature
difference between the hot and cold ends. With this J-type thermocouple, students will measure
the temperature of water coming to a boil and will also record the voltage associated with each
measured temperature. Then, students will calculate the theoretical voltage of the thermocouple
and determine the percent error between the experimental and theoretical data.
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Experimental Procedures
1. Gather all of the lab equipment needed.
2. Connect to the computer with the InstruNet World Software on it.
3. Place two J-type thermocouples in the wiring box connected to the computer with the
appropriate software. (See Figure 1)
4. Place one thermocouple in slot 7 and the other in slot 15
5. Select the correct setting on the InstruNet Software.
6. Select slot 7 so that it measures temperature in Celsius and slot 15 measures voltage.
7. Place the thermocouple in a beaker filled with water that is connected to the computer
(See Figure 2 )
8. Start the program and turn on the hot plate under the beaker
9. Record all data and clean workspace when done.
Figure 1: J-type thermocouple in wiring box
Figure 2: Thermocouple in beaker of water connected to the computer
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Results
Table 1: Experimental Data
Experimental Data
Temperature (˚C)
Voltage (mV)
30
0.0228
35
0.244
40
0.509
45
0.775
50
1.04
55
1.26
60
1.57
65
1.84
70
2.1
75
2.37
80
2.63
85
2.9
90
3.16
95
3.43
100
3.56
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Table 2: Theoretical Data
Theoretical Data
Temperature (˚C)
Voltage (mV)
30
1.537
35
1.797
40
2.059
45
2.322
50
2.585
55
2.850
60
3.116
65
3.382
70
3.649
75
3.912
80
4.187
85
4.456
90
4.727
95
4.997
100
5.269
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Table 3: Percentage Error of Voltages
Percent Errors
Experimental Voltage
(mV)
Theoretical Voltage Percent Error
(mV)
(%)
0.0228
1.537
98.5
0.244
1.797
86.4
0.509
2.059
75.3
0.775
2.322
66.6
1.04
2.585
59.8
1.26
2.850
55.8
1.57
3.116
49.6
1.84
3.382
45.6
2.1
3.649
42.4
2.37
3.912
39.4
2.63
4.187
37.2
2.9
4.456
34.9
3.16
4.727
33.1
3.43
4.997
31.4
3.56
5.269
32.4
Figure 3: Voltage (mV) vs Temperature (℃)
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Discussions
For the lab, students measured the temperature of boiling water using J-type
thermocouples. Seen in Table 1 and 2 the starting temperature for this lab is 30 degrees celsius
and went to 100 degrees celsius. As the temperature went up so did the voltage. After converting
the volts to millivolts from the original data (by using a thermocouple reference chart) students
then plotted the theoretical data and found the percent error seen on Table 3. The percent error
decreased as the temperature went up. The high percent error could be due to an inaccurate read
from the thermocouple wires, the computer software, or human error. To avoid these challenges
in the future, I would suggest newer and more reliable laboratory equipment and conduct
additional trial runs.
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Conclusion
In conclusion, based on the results of the lab students were able to understand the
function and concept of J-type thermocouples. Using the thermocouple teaches students the
relationship between temperature and voltage. The experimental data supports the conclusion
that the behavior of J-type thermocouples is dependent on the variables of temperature and
voltage. It reveals a direct relationship between temperature and voltage in thermocouples. As
well as the high percentage error at the experimental temperature, which proves that the error
was caused by human error.
References
● Dr. Mohammad Kamal Hossain. (n.d.). MEASUREMENT OF TEMPERATURE
USING J-TYPE THERMOCOUPLES. Tuskegee, AL; Tuskegee University.
● Thermocouple Calculator, https://gock.net/thermocouple-converter/.
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Appendix
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