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

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

Extracts from this document...

Introduction

##### Aim

To investigate the relationship between temperature and resistance in a thermistor.

##### Introduction

A current is the flow of charge round a circuit, this can be in the form of ions in a liquid or electrons in a metal.

Resistance is anything that slows the flow of electrons round the circuit.

Ohm's law states that the voltage is equal to the current multiplied by the resistance - V=IR

This can be re-arranged to say R=V/I.

Ohms law states that in a metal component the ratio of voltage to current remain constant, meaning that the resistance stays the same as long as the temperature remains the same. In this experiment I will be changing the temperature therefore this rule will not apply, however the equation R=V/I is always true as it is the way resistance is defined.

In a wire when the temperature is increased the resistance increases. This is because at a higher temperature the lattice atoms are vibrating faster and are colliding with the electrical current and slowing down the flow of charge.

This is also true in a thermistor but there is another competing effect because it is a semiconductor. Being a semiconductor means that the outer electrons are not free at room temperature but when heated the get more energy and are freed. This means that there are more electrons available to conduct.

Middle Experiment Diagram

##### Results
 Temperature (0C) Current (A) Voltage (V) Resistance (Ohms) Average Resistance (Ohms) Trial 1 Trial 2 Trial 3 Trial 1 Trial 2

Conclusion

0C and see if the resistance would start to increase again after the thermistors atoms have lost all their outer electrons and the lattice atoms continue to move faster slowing down the flow of current. I could not use water to do this as water can not be heated beyond 1000C, I would have to use a liquid with a higher boiling point such as oil. For this experiment I would set up the equipment in the same way but use oil instead of water and continue beyond 1000C. I could also investigate whether the length of a wire had an effect on the resistance of the circuit there would be more lattice atoms and may be a higher resistance.

I would also like to try lower temperatures to see if there was a minimum energy needed to free the electrons if so the graph would be- 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

# Related AS and A Level Electrical & Thermal Physics essays

1. ## Investigate how the temperature affects the resistance of a thermistor.

The type of flame I use to heat my water/oil bath must also stay constant because different types of flames give off more heat for example a roaring blue flame gives off a lot more heat than a large yellow flame (the safety flame)

2. ## 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.

1. ## Investigating the relationship between pressure, volume and temperature of a gas

Improvement 1. The rubber tubing used should be as short as possible. 2. More accurate apparatus should be used. 3. For (II), vaseline is used to grease the junction in the round- bottomed flask. Conclusion In experiment (I), the length of air column h represents the volume of air V since V is equal to h x cross-sectional area of the column.

2. ## Investigating the effect of 'length' on the resistance of a wire

Dependant variable * The resistance of the wire. This is calculated by measuring voltage and current. This represents the effect of varying the length of a wire on resistance. Reliability Confidence in the truth of the results I will repeat each reading twice to make sure results are fair and true and then take the average.

1. ## Effect of changing the temperature on the resistance of a thermistor

Voltmeter(V) 35? 0.0Slop014 1.4 35? 0.0017 1.6 40? 0.0015 1.3 40? 0.0018 1.6 45? 0.0017 1.2 45? 0.002 1.6 50? 0.0018 50? 0.0022 1.2 55? 0.0021 1.2 55? 0.0024 1.2 60? 0.0022 1 60? 0.00245 1.1 65? 0.0023 1 65? 0.0026 1 70? 0.0025 0.95 70? 0.0028 1 75? 0.0025 0.9 75? 0.003 0.9 80? 0.0028 0.8 80?

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

Prediction: From the information above I predict that as I increase the temperature of the thermistor by heating it in a beaker of oil in a water bath, the resistance, measure in Ohms (?), will decrease. This is because a thermistor is a semi-conductor and so as the particles in

1. ## The aim of the experiment is to verify the maximum power theorem and investigate ...

3.88 3.88 5.84 5.84 7.81 7.81 In the experiment, we have made several assumptions: 1. Air resistance is neglect 2. The friction is evenly distributed on any surface of the sand paper (i.e. the friction should be the same over the whole sand paper.)

2. ## An Investigation into how electrons move

We each timed one of the crystals which increased the error in timing due to differing reaction times but we felt this would be better than having one person attempt to time all three crystals to avoid confusion and further human error. • Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to 