<^< Ohm's Law | Course Index | Energy and Power >^>
| Objective:
| To carry out measurements of the applied voltage, and current flowing, in a fixed resistor and to verify that Ohm's Law is obeyed.
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| Underpinning knowledge:
| Voltage, current and resistance. Ohm's Law.
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| Apparatus:
| TINA circuit file, or apparatus to make the following circuit.
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| TINA Circuit File:
| Click here to download circuit file
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| Initial Settings:
| V = 2V, R = 4kΩ
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| Requires:
| Paper, Linear graph paper, pen or pencil.
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| Instructions:
(a) Using TINA or apparatus with the initial settings as listed above verify that V = I x R
(b) Vary the applied voltage (V) from 0V to 10V in 1V steps and record the current (I) at each step.
(c) Plot a graph showing how I varies with V.
(d) Repeat (b) and (c) with R=2kΩ and R=8kΩ.
If possible, use the same set of axes for all three graphs.
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Observations:
(a)Is Ohm's Law obeyed?
(b) What information can be obtained from the graphs of I plotted against V?
(c) On what does the slope (or gradient) of the I/V graph depend?
(d) Does a steep slope correspond to a high or low resistance?
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| Further work:
The straight line graph tells you that the resistance remains the same for different values of applied voltage. Many electronic components do not have a straight line I/V characteristic - what does this tell you about their resistance?
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<^< Ohm's Law | Course index | Energy and Power >^>
