How Does Voltage Affect Current
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Introduction
Charlotte James
10St
How Does Voltage Affect Current
Through a Filament Lamp?
Equipment:
- Power Supply. (Ranging from 0V to 6V).
- Variable Resistor.
- Ammeter.
- Voltmeter.
- 6V Filament Lamp.
- 7 Wires.
Definitions:
Ammeter - This is a device that measures the current of electrons in Amps. It has to be placed in Series on the circuit.
Voltmeter - This is a device for measuring the potential difference of the electrons in the circuit. They are measured in Volts. It is placed in Parallel.
Variable Resistor - This acts in the same way as a normal resistor, to resist the current, but this one can have a variable (changeable) resistance. In this particular circuit, it is in Parallel
Circuit Diagram:
Plan:
- To draw a circuit diagram.
- To make a prediction of what might happen during the experiment and what the results may be like, and use previous knowledge or science knowledge to explain the prediction. Also to predict what shape line/curve the graph might show.
- To build a circuit using the equipment mentioned above, following the circuit diagram.
- To increase the voltage gradually by 0.5V each time, starting at 0V and finishing and 6V.
- To record the current after each voltage change. Readings shall be extremely accurate, as they are taken in Milliamps (a thousandth of an Amp).
- To repeat the experiment twice to ensure Ammeter readings are accurate.
- To make a table of results, showing the 1st and 2nd set of results and an average of the two.
- To use the results table to draw up a graph to showing how the voltage affects the current through a filament lamp.
- Finally to use the graph to see how voltage affects current through a filament lamp.
Middle
1st
2nd
Average
(3dp)
0.0
0.000
0.000
0.000
0.5
0.075
0.073
0.074
1.0
0.105
0.103
0.104
1.5
0.130
0.128
0.129
2.0
0.152
0.149
0.151
2.5
0.187
0.169
0.171
3.0
0.190
0.187
0.189
3.5
0.207
0.204
0.205
4.0
0.223
0.220
0.222
4.5
0.283
0.235
0.237
5.0
0.252
0.249
0.251
5.5
0.267
0.263
0.265
Conclusion/Analysis:
Through experimenting, I have found out about how the current increased as the voltage increased. However the rate of increase slowed down after around 3.
Conclusion
- How could you improve your experiment?
The experiment could be improved in a couple of ways, one being the amount in which the voltage was increased by. For example, the voltage would still range from 0V to 6V but instead of having 0.5V intervals you could have 0.25V. You could also do more repeat readings, so the average result was more exact.
- How could you further your investigation?
Different lamps with different voltage limits could be used. E.g. the lamp used in my experiment had a limit of 6V, instead of this you could try a 2V or 20V lamp.
You might try using a larger amount of lamps. E.g. have a circuit that included 4 or 5 lamps and seeing how this affected the resistance, if at all.
As long as it was done safely, you could try going beyond the limit of the lamp. E.g. going to 6.5V or 7V on a 6V lamp and finding out what happened then.
- Was your prediction correct?
No. I predicted a straight line on the graph. But looking at the graph and thinking about what happened during the experiment, it makes sense why the graph would show and upward curve.
This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics section.
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