Thermistor Digital Thermometer

Thermistor Circuit

A thermistor is a special type of resistor whose resistance changes significantly with the temperature.


Typical Operating Temperature Range: -67 to 490F (-55C - 250C)

 Voltage DividerHere we have two regular 10K resistors in series, configured as a voltage divider. This is a way to use resistors to set a specific voltage. If we start with 5V and measure in between the two 10K resistors we get 2.5V, half of the source voltage.


 If we connect this junction to a microcontroller’s analog input we can read this voltage and run a formula to convert that reading into a temperature…

then we send that reading to a display.

I added a button and additional code to switch between Celsius and Fahrenheit.

Because of the tolerance in the various components, we can’t expect this to be 100% accurate straight away. So I’m going to replace the other 10K resistor with a potentiometer so we can have a way to calibrate it.


A thermistor is another highly valuable sensor you can add to your DIY toolkit. You can buy a pack of 50 for like $7 on Amazon!

This project is more than a practical tool, it’s an excellent introduction to the world of electronics and Arduino.

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