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

Aim To build and test a temperature sensor and analysing its suitability as a bath water thermometer.

Extracts from this document...


Physics Sensing Coursework - Temperature sensor Aim To build and test a temperature sensor and analysing its suitability as a bath water thermometer. Introduction In making a temperature sensor the circuit and individual components need to be thought about. Also I need to find a way of measuring my sensor to calibrate its voltage output with the temperature it's measuring. First of all I require a component in my circuit which will change its electrical properties in the changing of temperature. This component is called a thermistor and there are two types; * The positive temperature coefficient thermistor or PTC thermistor has an increased resistance as temperature increases. ...read more.


For this circuit I will use a simple NTC thermistor which changes variably, not suddenly, with change of temperature. This works by having the thermistor made of a semiconductor and works because raising the temperature of a semiconductor increases the number of electrons able to move about and carry charge, the more charge carriers that are available, the more current a material can conduct and so resistance decreases. Another component I could use for this is a thermocouple. This is made by twisting two wires of differing metals (best is an antimony-bismuth thermocouple) together and having junctions, where the wires are twisted more, placed in a high heat, the following junction cold and this produces a voltage output. ...read more.


The Wheatstone bridge cicuit would look like this; In this circuit all resistors are of equal resistance and so as in the potential divider as the temperature changes and the thermistor resistance changes so does the voltage output. The main difference between the two is that the Wheatstone bridge helps to eliminate noise as fluctuations from the power supply affect both sidesof the bridge. Having done some preliminary testing I found the school power packs to have few fluctuations that shouldn't be worried over. Because the potential divider has less wires and is much simpler and the power pack doesn't affect the results I will use the potential divider circuit in my system. Appartus Water bath Wires 12V power pack Digital multimeter NTC thermistor (about 47k?) 47k? resistor Temperature probe Data logger Diagram ...read more.

The above preview is unformatted text

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.

    o Ohmmeter o Thermometer Diagram: Method: As in the diagram I will firstly set up all my equipment so that I have a tripod, mat and gauze set up. I will have the beaker half filled with water because this is enough to heat the test tube effectively with out the hazard of the water boiling over or spilling out.

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

    negative number and as this is impossible I would assume that from that point the resistance would be 0? if the temperature went any higher. Another possibility is that I would not reach a point of no resistance but instead level out at a resistance slightly above that because it

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

    As the temperature of the pencil lead increases so does the resistance and vice versa meaning the results become less reliable. The reason why it will be hard to control is that body heat will warm up the room as will the temperature that the wire emits etc.

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

    I therefore recorded the values of time to the nearest second. * First I added extra lagging to my aluminium block making sure that the top of the heating filament and thermometer hole is covered to prevent heat loss. * Connect circuit as shown in the diagram above.

  1. physics sensor coursework

    to block off more light; but if the light intensity is below desired value, move the opaque object away from the sensor, so more light falls on the LDR. v. Continue steps (ii.) and (iii.) until required value of light intensity is achieved.

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

    A Bunsen burner was used to heat the water and for every 5�C increase in temperature (as observed on the thermometer),, the resistance of the thermistor was recorded (between 25�C and 80�C). At 80�C, the Bunsen burner was switched off and the water was allowed to cool, again measuring the

  1. Investigating how temperature affects the resistance in a wire

    I have used the treadline as a basis for this conclusion because the results have a weak correlation, and the linear treadline is therefore nearer to the theoretical result. However, the weakness of this negative correlation raises the notion that the results have no correlation at all.

  2. Experiments with a thermistor

    Record the voltage reading on the digital multi-meter. * Repeat the procedure for every 10oc interval down to about 20oc, which is approximately the minimum temperature that the water can reach. * Place several blocks of ice cubes into a clean beaker, and crush the ice into small pieces to increase its surface area.

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