• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11

Investigation in to what happens to the resistance of a thermistor as its temperature changes.

Extracts from this document...

Introduction

Physics Coursework

Danielle Roots

Mr Small

Aim:  To investigate what happens to the resistance of a thermistor as its temperature changes.

What is a thermistor?

Is a resistor that changes in resistance with temperature.

“Its principle characteristic is that their electrical resistance changes in response to changes in their temperature.”

http://www.betatherm.com/therm_theory.html

Symbol for a Thermistor:

image12.pngimage16.pngimage00.pngimage01.png

Calculating resistance

Resistance in a circuit can be calculated using the levels of voltage and current in a wire or a single component.

The formula we use to measure resistance is:

RESISTANCE = VOLTAGE                        R = V

                      CURRENT                          I        

What is Current?

Current is the flow of electrons around an electric circuit.

It is measured in amps.  Current is measured in Amps.

1 amp = 1 coulomb per second

Per means divided by so current = charge

                                           time        

image18.png

image32.pngimage03.pngimage33.pngimage27.pngimage31.pngimage02.pngimage23.png

image04.png

image05.png

...read more.

Middle

image25.pngimage22.pngimage26.pngimage21.pngimage14.pngimage24.pngimage13.pngimage20.pngimage13.pngimage13.pngimage15.pngimage15.pngimage26.pngimage24.pngimage20.pngimage25.png

image28.pngimage13.pngimage21.pngimage29.pngimage30.pngimage13.pngimage13.pngimage15.pngimage28.png

[image19.pngimage15.pngimage19.pngimage13.pngimage29.pngimage24.pngimage30.pngimage15.pngimage29.pngimage15.pngimage21.pngimage28.pngimage20.pngimage26.pngimage25.png

image25.pngimage21.pngimage29.pngimage24.pngimage30.png

Parallel Circuits    

image34.png

 Series Circuits  

Only has one path for the charges to move along. Charges must move in "series" first going to one resistor then the next. If one of the items in the circuit is broken then no charge will move through the circuit because there is only one path. There is no alternative route.

image35.png

In a series circuit voltage decreases as it travels around the circuit as the energy is being used up.  The current however will stay the same wherever it is measure around the circuit.  

The voltage used on each component add together to equal the reading from the voltage source.  Linking this to the equation   V = R

                                                            I        

And the higher the voltage is going to be because the higher the resistance is because the current stays the same.

Ohms Law

Ohms law clearly states that

Resistance =  Voltage

                    Current

...read more.

Conclusion

The same thermometer or at least the same type of thermometer I will use a liquid thermometer all the time because the readings I get could be different because of a thermometer being too or not accurate enough compared to other thermometers I used previously but in the same investigation.When I repeat results if I have time I want to wait until the thermistor cools down so this doesn’t affect the results because the heat of the thermistor could be different from that of the water and the results I get aren’t correct because the current and voltage results I am taking aren’t in relation to the temperature of the water because doing this experiment I am assuming he thermistor is the same temperature as the water.

Safety

  • I have to make sure none of the wires are in the water or are on something hot in case they burn etc.
  • When taking apparatus apart I need to make sure that I am careful I don’t burn myself
  • That I wear goggles in case of any fires or water boiling and bubbling into eyes.
  • That I don’t fill the water up too high on the beaker in case it splashes out and burns someone

Prediction

Scientific Theory

...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. The aim of my investigation is to determine the specific heat capacity of aluminium.

    Heat is transferred relatively slowly from the heating filament to the aluminium block through convection current within the air, which is in the space between the filament and the block. Conduction then takes place, which transfers the heat through out the block .

  2. Experiments with a thermistor

    A cardboard 'wall' can be excluded in this case. * The change in output was not largely significant, with a rise of only around 0.01-0.08 V for each reading taken, and I was only able to obtain distance values for up to 16cm.

  1. Characteristics of Ohmic and non-Ohmic Conductors.

    In some circumstances it is possible for an electron in the lower band to gain enough energy to jump into the higher band and become a charge carrier. As the temperature of the conductor rises, the amplitude of vibration of the atoms increases and drifting electrons then make more collisions with atoms.

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

    are colliding with the electrical current and slowing down the flow of charge. In a normal wire this would make the resistance decrease but because a thermistor is a semiconductor there is a second stronger effect which out weighs this.

  1. Investigation into the resistance of a filament lamp.

    would be around 12 Volts so therefore I decided to set the power supply to 12V. After choosing the DC voltage power supply, I had to choose different ranges of voltage each time, I concluded that it would be best to start from 0.5 volts and to finish at 12 volts, increasing in steps of 0.5 volts each time.

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

    With two batteries the voltage fluctuates as the temperature rises, only decreasing 0.2 volts. With three batteries in the circuit the voltage fluctuates as the temperature rises. It fluctuates around the point 4.5 volts, with the greatest decrease of 0.2 volts and the largest increase of 0.2 volts.

  1. Investigating a Thermistor.

    as I thought that although the mixture was being methodically stirred, temperature might vary at different depths of the beaker. After performing the first experiment, I thought that as well as using 25ohms suggested by my algebra, I would do experiments with 5 and 105ohms (shown to be the extremes

  2. To 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.

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