Overview
Week 7 at a Glance
Gauge factorStrain rosette configurationsLoad cell calibrationThermocouple + CJCRTD three-wire circuitNTC thermistor (Steinhart-Hart)
Why it matters in practice. Strain and temperature are the two most commonly measured physical quantities in mechanical engineering. The sensor families you learn this week appear in aerospace structural testing, automotive validation, materials characterization, and process control.
Objectives
What You Will Be Able to Do
Course objectives (CO) define program-level skills. Module objectives (MO) define specific weekly targets that build toward them.
Course Objectives (CO)
CO6: Select appropriate sensors; predict sensor output from calibration data; identify sources of measurement error.
CO3: Design signal conditioning circuits to meet target performance specifications.
Module Objectives (MO) — Week 7
Compute strain gauge output voltage using gauge factor, bridge configuration, and Poisson's ratio for a given applied stress.
CO6
CO6
Interpret strain rosette data to compute principal strains and maximum shear strain.
CO6
CO6
Predict thermocouple output voltage and apply cold-junction compensation to obtain corrected temperature.
CO6
CO6
Analyze an RTD circuit (two-, three-, or four-wire) and estimate the error due to lead resistance.
CO6
CO6
Linearize NTC thermistor resistance using the Steinhart-Hart equation and compute temperature from resistance.
CO6
CO6
Review these objectives before you start each assignment. They map directly to what is assessed on the quiz, homework, and exams.
Suggested Learning Path
How to Work Through This Week
Follow this sequence. Each step prepares you for the next. Do not attempt graded work before completing the instructional material it depends on.
1
Read Alciatore Ch. 10-11 (assigned sections)
Gauge factor derivation in Ch. 10 and thermocouple/RTD/thermistor theory in Ch. 11. Work through the cold-junction compensation example before lecture.
2
Attend Lecture
Lecture 1 covers strain gauges and rosettes. Lecture 2 covers thermocouple, RTD, and thermistor signal conditioning. Each lecture includes a hardware-grounded problem session.
3
Lab: NTC Thermistor Characterization on Arduino
Acquire resistance vs. temperature data over a 10°C range using an ice bath and hot water reference. Fit the Steinhart-Hart coefficients using least squares. Report results with full Kline-McClintock uncertainty.
4
Begin Module 4 Homework
Module 4 Homework covers Weeks 7-10 content. Starting now on the strain gauge and thermocouple problems gives you buffer time for the more complex sensor fusion problems in Week 10.
Instructional Material
Required Readings, Videos, and Resources
Complete all required items before moving to graded activities. The Aligns to column maps each resource to the module objectives it directly supports.
| Resource | What You Will Gain | Aligns to | Est. Time |
|---|---|---|---|
| Read Alciatore Ch. 10 (Strain/Force) and Ch. 11 (Temperature) — assigned sections |
Gauge factor, rosette geometry, bridge configurations for bending and torsion, thermocouple Seebeck effect, Peltier effect and CJC, RTD linearization, and Steinhart-Hart equation. | MO1-MO5 | 90 min |
| Lab Lab: NTC Thermistor Characterization (Arduino) |
Hardware-anchored experiment: measure resistance vs. temperature, fit Steinhart-Hart coefficients with least squares, compare to manufacturer data. | MO5 | ~2 hr lab |
| Watch Micro-lecture: Cold-Junction Compensation in 3 Minutes |
Visual explanation of why a thermocouple measurement includes the reference junction temperature and how CJC chips eliminate this error. | MO3 | 3 min |
Graded Learning Activities
Assignments and Due Dates
All graded work is submitted through Canvas. Complete the listed prerequisites before attempting each assignment.
| Assignment | Prerequisites | What Is Assessed | Aligns to | Points |
|---|---|---|---|---|
| Module 4 Homework: Advanced Sensor Systems End of Week 10 |
Complete Ch. 10-11 readings and attend both Week 7 lectures before starting strain gauge and thermocouple problems. | Gauge factor calculation, rosette analysis, thermocouple CJC, RTD lead resistance error, and thermistor Steinhart-Hart fitting. | MO1-MO5 | 50 pts |
Academic integrity. Your thermistor characterization data must come from your own hardware session. The Steinhart-Hart coefficients you report must be derived from your measured data — do not use manufacturer coefficients as a substitute.