• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The effect of temperature on the resistance of a thermistor

Extracts from this document...


Jon Quere                

Physics Coursework

The effect of temperature on the resistance of a thermistor

Aim: The aim of this experiment is to find out whether temperature affects the resistance of a thermistor.


  • The temperature.
  • Type of ammeter.

I will be investigating whether or not a change in temperature of water to find out whether or not it will affect the resistance of a thermistor.

I will be keeping the following variable the same:

  • The power supply.

I will be taking readings of the temperature, volts, amps and resistance. I will be using a digital voltmeter, ammeter and thermometer for more accurate results. I will also be repeating the experiment at least twice and getting an average. I will be measuring and recording my results in amps, volts, resistance and degrees Celsius.




Bunsen burner






Power pack

Electric leads


This diagram shows the electrical circuit involved:


This diagram shows the apparatus set up:


 Current- This is a measure of the flow of electrons around a circuit (measured in Amperes or Amps (A))


...read more.


I predict that the graph will look something like this:


Explanation of prediction:

In my prediction I have stated that a change in temperature will affect the resistance of the thermistor.

In general an increase in temperature increases the resistance of metal but decreases the resistance of semiconductors. The resistance of most thermistors decrease as their temperature rises. In my case the resistance theoretically will in fact decrease as I raise the temperature.

The electrons in the heat energy produce resistance in the electrical circuits. We can measure ho w many electrons have effected the thermistor by measuring the current and the voltage.


Scientific theory

The current and voltage of an electric circuit, is given by the formula V=IR. This is known as Ohms. Ohm´s Law is only applicable, when the temperature of the resistor is kept constant. Therefore Ohms law is only applicable to Ohmic conductors. Examples of Ohmic conductors are metals and alloys at constant temperatures. Anything that doesn’t obey Ohms law, are know as non-Ohmic Conductors.

...read more.


My prediction says that the resistance will decrease with an increase of temperature I can now verify that with the help of my results and graph.


In all I think my experiment was very successful.  I did not run into any difficulties except for one minor problem. This problem was not picked up in my preliminary experiment but was a factor that affected my main experiment. This problem was that the volt meter was dysfunctional at the temperature of 80 degrees or above.  The results I obtained were all of a good quality.  I believe they are of good quality as I had just one result that showed up to be out of place.  All of the other readings again correspond to my prediction and analysis.  The one odd result was probably due to an inaccurate reading of the ammeter or the voltmeter.  Although I feel that my experiment was successful if I were to do it again I would change one or two things. One of these things would be repeating the experiment at least five times and finding averages.

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Electrical & Thermal Physics essays

  1. Investigate how the temperature affects the resistance of a thermistor.

    more energy is going into the valence band. This energy allows electrons to jump the gap and flow along the conduction band. The higher the potential difference the hotter the component will get and the more electrons that will jump into the conduction band. This is why when a thermistor is heated the resistance decreases.

  2. Thermistor Coursework

    2.29 27 2.27 28 2.25 29 2.21 30 2.10 31 2.07 32 2.01 This graph shows me what potential difference the potential divider will give out when the temperature output is 20°C and 30°C, information that could be used to calibrate a circuit that can open and close the windows, and turn the heaters on inside the greenhouse.

  1. To investigate how the temperature affects the resistance of a thermistor.

    All equipment must be kept the same in my experiment. The thermistor must be the same one throughout because different sizes of thermistors react differently to heat and they can be made in different ways to react more or less with heat than others.

  2. physics sensor coursework

    It would already be unnecessary because the voltage output reading would already have experienced the drop in voltage due to internal resistance. Therefore, internal resistance does not need to be taken in account. The final aspect to consider is the linearity of the circuit.

  1. Characteristics of Ohmic and Non-Ohmic Conductors.

    Filament lamp - as more current flows through the metal filament, its temperature increases. The increase in temperature causes an excess amount of vibrations between the atoms, and this constant vibration obstructs the flow of electrons, thus decreasing the current, and increasing the resistance.

  2. Characteristics of Ohmic and Non Ohmic Conductors.

    So the electrons are accelerated and gain velocity and energy. They will collide with atoms that are vibrating in their lattice site and give some of their energy to it. When they slow or stop the energy is again provided to them by the electric field and they accelerate.

  1. Physics coursework

    However there still may have been some slight differences in temperature between the point, which was being measured by the thermometer, and the thermistor. Therefore, next time it would be a good idea to stir the water constantly. Further more the voltmeter may have needed to settle, but because the

  2. An Investigation into the Resistance of a Thermistor, its Application as a Sensor and ...

    25 457 228.5 30 377 188.5 35 308 154 40 257 128.5 45 215 107.5 50 180 90.0 55 149 74.5 60 123 61.5 65 105 52.5 70 89.1 44.6 75 75.8 37.9 80 65.8 32.9 This tells us that between 25�C and 80�C, we would need a variable resistor

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work