Many thermostats hide a thermistor: a bead whose resistance falls as it warms. In a divider it turns heat into volts for the ADC. The curve isn’t straight, so firmware uses the Beta equation or a table.
Why pick a fixed resistor equal to the thermistor’s room-temperature value? Tell me in the comments.
Explore the notes: https://mrintegral.com/embedded/
#Electronics #Sensors #EmbeddedSystems #Arduino #Thermistor