Assignment Flashcards
Aim
To Investigate how changing the temperature affects the resistance in a thermistor
Underlying Physics Part 2
-Thermistor is a condensed version of the words thermally sensitive resistor
-It is a temperature sensor made from metal oxides which show obvious change in resistance with temperature such as manganese, nickel or copper
-Thermistors can be used to measure the temperature of liquids as well as surrounding air
Underlying Physics Part 2
There are 2 types of thermistors
-NTC thermistors (negative temperature coefficient) which decrease their resistance when exposed to changes in temperature
-PTC (positive temperature coefficient) which increases their resistance when exposed to changes in temperature
Underlying Physics Part 3
-Thermistors have many advantages such as being easily procured, cheap to produce and provide very accurate figures.
-However there area few disadvantages as they are prone to self heating (current must be as low as possible to prevent this) and can only operate within a limited temperature range.
Underlying Physics Part 4
-Thermistors are crucial is day to day life as well as the professional environment
-They are used in digital thermometers, cars to measure oil and coolant temperatures and in household appliances such as ovens and refrigerators
-The professional uses a lazer stabilization detectors, optical blocks and charge coupled devices.
Method
- Set up a circuit according to the diagram below: Ω connected to thermistor
- Fill a beaker with boiling water and submerge the thermistor and thermometer
- Wait until the temperature of the thermometer to rise to to the temperature of the water before starting
- Whilst the experiment cools, record values of the resistance from the ohmmeter at various temperatures
Analysis
-My results shows that as temperature decreased, the resistance increased. Temperature and Resistance are inversely proportional
-This is the same for my 2nd source as temperature decreased, the resistance also increased.
Conclusion
In my investigation of how changing temperature affects the resistance in a thermistor, I found that as temperature decreases, the resistance will increase. Temperature and Resistance are inversely proportional.
Evaluation
-One thing I would change would be to measure a wider range of temperatures rather than just 80-60 as it provided a graph that didn’t show as prominent a graph as preferred. Increasing the range of temperatures would provide a clearer graph and improve the accuracy of my experiment as this would increase the accuracy of my experiment
-Another thing I would have done was to measure the amount of water I was using.
-As the experiment takes a long time, I had to do it over 2 days resulting in slightly different answers for Set 1 and 2 compared to Set 3. Measuring the amount of water would of increased the reliability of my figures
