Thermistor mystery

I was working with some thermistors for a recent project, I’m making a WiFi fridge sensor that sends data via MQTT, anyway, it uses a thermistor as the temp sensor and the ones I got did not come with a good datasheet. The datasheet for my part did not include any data on the temperature/resistance curve! Most good thermistors will come with the curve information in their datasheets and infact some will even include the Steinhart-Hart coefficients, but this did not. The part in question is a Cantherm MF52A2103J3470 and I had to figure out the curve on my own.

The process that I followed was to use a thermocouple I had connected to a multimeter to get known temperatures and then use another multimeter to check the resistance of the thermistor at those known temperatures. I ended up grabbing the following data points:

-26C = 96.3K
+4 = 24.1K
+39 = 5.5K

Once I had those datapoints I could drop them into this thermistor calculator:

The calculator then produced the following coefficients for the Steinhart-Hart equation:


With those coefficients I was able to calibrate my thermistor to a reasonable level of accuracy!

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