Thermistor
A thermistor is a resistor whose resistance changes strongly with temperature.
Part images
What it is
A thermistor is a resistor whose resistance changes strongly with temperature.
How students use it
Students use it for thermometers, room-temperature monitors, heat/cold alarms, and analog math practice with a real sensor.
Pins and power
Two non-polarized leads. Either lead can face either direction.
Passive sensor. Use it in a 3.3V voltage divider with a fixed resistor before connecting to Pico ADC.
SunFounder uses an NTC thermistor: resistance decreases as temperature rises. The kit thermistor is described as 10k ohm at 25C with beta value 3950.
Voltage and safety
Use 3.3V for the divider high side. Do not connect ADC pins to 5V.
Use room-temperature experiments. Do not heat the sensor with flame, high heat, or unsafe power sources.
Module internals
NTC thermistor bead/body, two leads, and resistive material whose resistance changes with temperature.
Datasheet notes
SunFounder gives the NTC conversion relationship and warns it is empirical and accurate only inside the effective temperature/resistance range.
Common libraries
Use machine.ADC for the divider reading, then convert resistance to temperature in lesson code.
Common mistakes
Using the wrong fixed resistor value in calculations, mixing Celsius and Kelvin, using 5V on the divider, and expecting medical-grade accuracy.