Characteristics of Thermistor


To study the temperature v/s voltage characteristics of Thermistor.


Thermometer, Heating coil, glass container, Thermistor trainer kit


A thermistor is a type of resistor whose resistance strongly depends on temperature. The word thermistor is a combination of words “thermal” and “resistor”. A thermistor is a temperature-sensing element composed of semiconductor material and sometimes mixture of metallic oxides such as Mn, Ni, Co, Cu and Fe, which exhibits a large change in resistance proportional to a small change in temperature. Pure metals have positive temperature coefficient of resistance, alloys have nearly equal zero temperature coefficient of resistance and semi conductors have negative temperature coefficient of resistance.


  1. Check connection made and switch ON the instrument by rocker switch at the front panel. The display glows to indicate the instrument is ON. 
  2. Allow the instrument in ON position for 10 minutes for 10 minutes for initial warm up. 
  3. Pore around 3/4th full of water to the kettle and place sensors and thermometer inside the kettle. 
  4. Note down the initial water temperature from the thermometer. 
  5. Select the sensor on which the experiment to be conducted through selection switch on the front panel. 
  6. Adjust the initial set potentiometer in the front panel till the display reads initial water temperature.
  7.  Switch on the kettle and wait till the water boils, note down the reading in the thermometer and set potentiometer till the display reads boiling water temperature. 
  8. Remove the sensor from the water and immerse it in cold water. Set the cold water temperature by using initial set potentiometer.
  9. Repeat the process till the display reads exact boiling water and cold water temperature. Change the water in the kettle and reheat the water. Now the display starts showing the exact raise in kettle.


Actual Temperature(oC)

Indicated Temperature(oC)

Output Voltage(mV)

Percentage Error( % Error)  = (Displayed temp – Actual temp)*100 /Actual temp



The temperature versus voltage characteristics of the Thermistor was studied and the accuracy of the signal conditioning board was studied.

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