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Thermistor (NTC 10k)

A resistor whose value changes with temperature; read it with a divider.

How it works

A thermistor is a resistor whose resistance changes a lot with temperature. The common NTC type drops in resistance as it warms. It's tiny, cheap, and fast — the temperature sensor inside many appliances.

Pair it with a fixed 10kΩ resistor to make a voltage divider, read the midpoint with analogRead, work out the thermistor's resistance, and convert to temperature with the Beta (or Steinhart–Hart) equation.

Pins

Leg 1
To +5V (with a 10kΩ from the junction to GND).
Leg 2
To the analog pin / divider junction.

Ratings

Typical
10 kΩ at 25°C (NTC)
Beta
~3950 K (check the datasheet)

Tips

  • Use a 10kΩ divider resistor to match a 10k thermistor.
  • Put the real Beta value from your part's datasheet into the code.