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

Exploring the characteristics of a sensor

Extracts from this document...

Introduction

Exploring the characteristics of a sensor

AIM:

The aim of my experiment is to measure the resistance of a thermistor at temperatures which are acceptable by the human body. I can then use this information to create a sensor that can be placed in a bath to record the temperature. This will be beneficial to people who cannot feel the temperature of bath water such as a person who has suffered from a stroke.

RESEARCH

To be able to do my experiment successfully I needed to find out a suitable temperature range to test on.  I found out that the human body tolerates temperatures from 25˚C to 45˚C. image00.png

I also decided to research thermistors. There are two kinds of thermistors; these depend on the sign of the resistance. If the resistance is positive, the resistance increases with the temperature and is called positive temperature coefficient (PTC) thermistor. If the sign is negative, the resistance decreases as the temperature increases. This is called a negative temperature coefficient (NTC) thermistor.  

VARIABLES

For my experiment to be a success I must make it a fair test.

...read more.

Middle

 – This will be connected in my circuit so I can measure the temperature of my circuit. The kind of thermistor I use will be kept the same to ensure a fair test1M wire – this will be connected to the meter bridgeGalvanometer – this measures the potential difference in my circuit. When the galvanometer is at 0 it means the two resistances are equal to each otherPower supply – I will use the same power supply at the same voltage to make it a fair test. Resistor – The resistor I use will be dependent on the reading from the multi meterThermometer – I will use a thermometer to measure the temperature of the water in the beaker. I will make sure the water is at the correct temperature before conducting my experimentWater – the water will be heated up using a Bunsen burner, I will then allow it to cool until it reaches the temperature I wish to measure. The amount of water I use will also be kept the sameBeaker – I will use a beaker to contain the water.
...read more.

Conclusion

>

41

61.0

39.0

0.95

30˚C

69

64

63

31

36

37

65.3

34.6

0.79

35˚C

71

70

72

29

30

28

71.0

29.0

0.61

40˚C

75

73

74

25

27

26

74.0

26.0

0.52

45˚C

79

78

79

21

22

21

78.6

21.3

0.40

50˚C

82

83

82

18

17

18

82.3

17.6

0.32

So I predict that as heat enters the thermistor the electrons subsequently can move around and become free, the current will then increase as the electrons flow around the circuit and the resistance will decrease as more energy is supplied to it. The Voltage should not increase or decrease by more than 0.2V and I expect that the current will increase proportionally until the experiments end.

...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.

    After this is down the test tube will be filled up with oil until it covers the thermistor but being careful not to put too much in it because this is not economical and is at risk of spilling or boiling over.

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

    could be the point at which the electrons left in the Valence band need more energy that can be given through heat in order for them to jump the gap to the conduction band. Conclusion: From my data that I have obtained from my investigation into the relationship between the

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

    Results 3 show a value less than expected as it is lower than the actual book value this is because the thermometer is too close to the centre of the block and is therefore recording a higher temperature than that of the average of the block.

  2. physics sensor coursework

    It is impossible to accurately change the light intensity with just blocking off the light. Instead, a trial-and-error method is adopted, where we continually move the book back and forth until there is the correct light intensity. There is also the problem of maintaining the light intensity at the same

  1. Experiments with a thermistor

    * For each temperature, the voltage reading on the multi-meter slightly fluctuated, therefore I had to repeat the experiment twice and calculate the average to minimise the percentage error of the values. EXPERIMENT #2 Investigation For the second experiment, I performed a similar kind of experiment, but from a different sort of perspective.

  2. Investigating how temperature affects the resistance in a wire

    In both graphs 3 and 4 the general pattern shows high range and high standard deviation at low temperature (high inaccuracy) and low range and low standard deviation at high temperatures (low inaccuracy). This therefore contradicts my earlier theory that the inaccuracy would increase with an increase in the temperature,

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

    resistance at the same temperatures as before (but this time as the temperature decreased). Safety Issues Goggles were worn for safety. Another safety precaution was the use of distilled water. Because electrical components were being submerged in the water, pure water needed to be used as any impurities in water

  2. Find The Internal Resistance Of A Power Supply

    three times for the five different voltage settings and this enabled me to record then calculate more accurate average potential difference and current values. From graphs 3 to 7, we can see that the points lie close to the line of best fit showing that my results follow a definite

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