Thermistors calculation of base resistance

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Discussion Overview

The discussion revolves around calculating the base resistance of a thermistor using a regression equation and determining the temperature of boiling water based on this equation. The scope includes mathematical reasoning and conceptual clarification regarding the variables involved in the equation.

Discussion Character

  • Exploratory, Technical explanation, Homework-related, Mathematical reasoning

Main Points Raised

  • One participant asks how to solve for the base resistance of the thermistor using the equation Y=1.54e^-0.059x.
  • Another participant questions whether this is a homework problem and suggests plotting the equation for temperatures from 0 to 100°C to study its shape.
  • There is uncertainty about the definitions of the variables, with some participants proposing that Y represents resistance and X represents temperature.
  • A participant mentions that the base resistance of a thermistor is typically defined at 25 °C and describes the expected shape of the resistance curve as NTC (Negative Temperature Coefficient).
  • At 100°C, a resistance value of 0.08 ohms is provided, but there is uncertainty about plugging in different temperatures to solve for Y.
  • Concerns are raised about the accuracy of measuring very low resistance values, suggesting that reliable answers depend on certainty regarding the numbers and units used.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the definitions of the variables and the calculations involved. There is no consensus on how to proceed with the calculations or the interpretation of the equation.

Contextual Notes

There are limitations regarding the assumptions about the variables and the context in which the resistance values are measured. The discussion does not resolve the mathematical steps or the definitions of the variables involved.

physocs1
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Using the regression eqn. Find the base resistance of the thermistor.
Find the temp. Of the boiling water using this eqn.

Y=1.54e^-0.059x

How do I go about solving this problem
 
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Is this homework?

Plot the equation for temperatures from 0 to 100°C and study it's shape.

What is meant by the base resistance of the thermistor?
Is Y the resistance?
Is x the temperature?
What was the thermistor resistance when in the boiling water?

Can you put the resistance into the equation?
 
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The resistance value of a thermistor at a specified temperature with negligible electrical power to avoid self heating. Usually base resistance will be defined at 25 °C.
Its a NTC looking shape
I think Y is resistance
X is temp.
Not sure

At 100C: R= 0.08

Could I plug in 25 C and solve for Y?? .
 
physocs1 said:
I think Y is resistance
X is temp.
Not sure
At 100C: R= 0.08
Could I plug in 25 C and solve for Y?? .
You need to find out for sure.
If x is resistance and y is temperature then you need to plug in the resistance to get the temperature.
R= 0.08 ohms is a very low resistance. It is so low that it would be very hard to measure accurately.
You cannot build a reliable answer if you cannot be sure of the numbers and the units.
 

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