How Easy Is It To Use A Thermistor?!

Made by Mirco Marcazzan

About the project

Thermistor as thermometer.

Project info

Difficulty:

Platforms:

Estimated time:

1 hour

Published:

4th July 2018

Items used in this project


Hardware components

Jumper wires (generic) x 1
Arduino UNO & Genuino UNO x 1
Resistor 10k ohm x 1
Thermistor NTC 10K x 1
Breadboard (generic) x 1

Software app and online services

Arduino Web Editor
Arduino IDE

Story


How easy is it to use a thermistor?!

In this article I will explain how to use a thermistor. First of all, what is it a Thermistor? A thermistor is a type of resistor whose resistance is dependent on temperature. There are two opposite types of thermistor:

  • PTC (Positve Temperature Coefficent), resistance increases as temperature rises
  • NTC (Negative Temperature Coefficent), resistance decreases as temperature rises

In this case I use NTC.

A little bit of math.

To calculate the thermistor resistance using a simple formula called equation with parameter B (with only NTC termistor).

Where:

  • e is the base of natural logarithm
  • R0 is the resistance of the thermistor measured at the temperature T0
  • B is a constant coefficient that depends on the characteristics of the material, it is a constant expressed in K, and its value is indicated by the manufacturers on the technical sheets

To calculate the temperature we need know the resistance RT using the Ohm's laws.

This is a schematic version of circuit.

RT = VRT / (VR/R)

Now we have all the data to calculate the temperature.

Remember to convert all parameters (for example T0) to Kelvin before the calculations, and also the result is in Kelvin.

This is the result.

Schematics


termistore_bb.jpg

termistore_schem.jpg

Code


Thermistor

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