This temperature sensor NTC Thermistor 10K waterproof 3950 .  A Thermistor is a temperature dependent resistor. The Thermistor used here is  of the type NTC (Negative Thermal Coefficient).  This means that the resistance of this thermistor decreases as the temperature increases.

Circuits with thermistors can have reasonable output voltages - not the millivolt outputs thermocouples have.  Because of these qualities, thermistors are widely used for simple temperature measurements.  They're not used for high temperatures, but in the temperature ranges where they work they are widely used.

Specifications and how to use

• NTC thermistor   10K
• 2 line output: length 300  cm
• Temperature Range: −40 °C to. +170 °C
• Accuracy: 1%

Click here for Excel sheet used to convert resistance and voltage value to temperature.

Click here for circuit and arduino code for using temperature sensor.

Click here for more examples on using the temperature sensor.