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

To conduct an experiment that proves that asensor is affected by temperature. In my experiment I will investigatethe effects of temperature on the resistance of a thermistor. I willuse a range of temperatures to see how it affects the resistanc...

Extracts from this document...


Alasdair Naisbitt

Sensing Coursework

Aim: To conduct an experiment that proves that a sensor is affected by temperature. In my experiment I will investigate the effects of temperature on the resistance of a thermistor. I will use a range of temperatures to see how it affects the resistance of the thermistor.

Safety: The main safety point in this experiment is that there is a high element of risk associated with the high water temperatures that will be reached during the course of the experiment. Common sense should be used at all times during the experiment by making sure to not put your hands in the Bunsen burner or pick up the beaker after it has been heated.

Electricity is also a key safety aspect. There should be no loose live wires and a qualified person must check all electrical equipment before use.

The combination of water and electricity can be dangerous so any spillages should be cleaned up as soon as possible. Lab rules should be followed at all times.

Preliminary Experiments: I have chosen to investigate the effects of temperature on a thermistor. However to make my experiment quicker, I needed to do some preliminary work. There are two types of thermistor – positive temperature coefficient and negative temperature coefficient.

...read more.










The results for the negative coefficient were taken to the nearest 5 ohms because accuracy was not important.

Sensor Terms

Sensor: Sensors are systems that measure or respond to changes in their surroundings. In this case the thermistor responds to changes in temperature by increasing/decreasing resistance.

A sensor is a device designed to produce an electrical signal in response to a change in its surroundings, either caused by a change in a specific physical variable or by the movement of surrounding objects.

Sensitivity: The ratio of output for a given input.

The sensitivity of a measuring instrument is the change of its output divided by the change in input.

A temperature sensor whose output changes by 100 mV for a change of 2 K in its input has a sensitivity of 50 mV per Kelvin.

In an instrument in which the change of the reading is directly proportional to the change of the variable causing the reading, a graph of the reading (on the y-axis) against the variable (on the x-axis) would be a straight line through the origin. The gradient of the line is equal to the sensitivity, which is the same across the full range of the instrument because the line is straight.

In a system or an instrument in which the change of reading is not proportional to the change of the variable causing the reading, the graph would be a curve.

...read more.


Poor connections in my circuit could have increased resistance so any of my results could have been anomalies.

Resolution: From my plotted graph of Average Resistance against Temperature, I obtained my resolution results by drawing lines from my error bars across to the line of best fit and then down to the x-axis. I then measured the distance between the vertical lines. My results are shown below:

Temperature (ºC)

Resolution (Ω/º)



















Conclusion: From my results I can state that as temperature increases, average resistance decreases. I can also state that I have no anomalies in my average resistance because the line of best-fit travels through every error bar on my graph.

When the temperature is low, the average resistance is very high and has large error bars. The results were very far apart and so producing an element of inaccuracy to my experiment.

From my results for resolution, I can conclude that my results show that as temperature increases, so does resolution.

I think that overall the experiment was conducted and executed well with no apparent disastrous inconveniences. There was however, a very small problem, which I encountered during the course of the experiment. The original thermistor that I began to use for my preliminary experiment decided to cease to function. This resulted in a loss of time, as I had to repeat my preliminary experiment so that any results conducted were not fair.

...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.

    the conduction band is by gaining enough energy to jump the gap. In metals the forbidden gap between the bands is extremely small and so it takes an extremely small amount of energy for the electrons to jump the gap as so electricity can flow very easily through all metals - this is why they conduct so well.

  2. Single Phase Transformer (Experiment) Report.

    These currents may be produced in a number of different ways, but a common method is to pass the anode current of a pentode through the primary winding of the scanning transformer with its secondary closed by a pair of deflecting coils.

  1. Investigate the relationship between temperature and resistance in a thermistor.

    I think that the second effect will be stronger because it increases the number of charge carriers. The second effect it stronger and this means that less of the current is stopped when the temperature increases and therefore the resistance goes down.

  2. I am going to investigate what the resistivity is of a pencil lead. ...

    then be able to work out the resistance of the pencil lead by looking at the graphs gradient (if it is an ohmic resistor). This is because the gradient is equal to the difference in y over the difference in x.

  1. Investigation into how the resistance of a thermistor varies with temperature.

    page 61, it states, "Thermistors are resistors whose resistance alters greatly as their temperature changes. Unlike wires, in the vast majority of these resistors have resistances that decrease as their temperature increases." The information on the DK GCSE Physics for PC and CD-rom reads thus "A thermistor is made from a semiconductor material.

  2. Effect of Temperature on resistance

    More obviously, I made sure that the two wires going into the thermistor did not cross, as that would short-circuit the circuit. I put the thermometer at the same level as the thermistor in the beaker, so they would be the same temperature.

  1. Experiments with a thermistor

    * Transfer all the values in tabular form and plot a graph of voltage/V against temperature/oc. Table of Values & Graph Temperature/oC Voltage/V1 Voltage/V2 Average V/V 0 5.04 4.98 5.01 10 4.30 4.32 4.31 20 3.77 3.67 3.72 30 3.18 3.26 3.22 40 2.70 2.80 2.75 50 2.33 2.51 2.42

  2. My aim is to investigate at which temperatures will give me which resistance and ...

    The most prevalent types of thermistors are glass bead, disc, and chip configurations (see Photo above). NTC thermistors exhibit a decrease in electrical resistance with increasing temperature. Depending on the materials and methods of fabrication, they are generally used in the temperature range of -50�C to 150�C, and up to 300�C for some glass-encapsulated units.

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