SBOA537 March   2022 TMP61 , TMP61-Q1 , TMP63 , TMP63-Q1 , TMP64 , TMP64-Q1

 

  1.   Trademarks
  2. 1Capturing the Data
  3. 2Creating the Plot for the Fourth-Order Polynomial
  4. 3Creating the Scatter Plot
  5. 4Creating a Polynomial for the Collected Data
  6. 5C Code
  7. 6Creating a Polynomial for an NTC
  8. 7Summary

6 Creating a Polynomial for an NTC

A polynomial curve fit does not work for an NTC. The main reason is that there are two points of inflection in the curve. A polynomial curve fit can only work with a curve that has only one point of inflection. As Figure 6-1 shows, when an NTC is plotted, the curve has two points of inflection so the fit is not good. Notice that even negative resistances are present in the curve fit.

GUID-65A83B2C-C7E7-4FA0-ABDC-A5141B51AEE2-low.png Figure 6-1 NTC Polynomial Curve Fit