IV Graph
Contents
Key Stage 4
Meaning
An IV graph is a graph showing how the current (I) through a component changes with the potential difference (V) across component.
About IV Graphs
- On an IV graph the potential difference is plotted on the x-axis and the current is plotted on the y-axis.
- An IV graph can be used to identify the characteristics of an unknown electrical component. This may be useful when inventing new components.
- The resistance of an component can change with the current or the potential difference.
- The resistance of a component can be found by taking the ratio of potential difference to current at a point on the curve of an IV graph.
Examples
The IV graph for a resistor shows that current is directly proportional to potential difference. | The IV graph for a bulb shows that as the potential difference increases the current increases. However, at large potential differences a change in potential difference causes a smaller increase in current for a change at small potential differences. |
The IV graph for a diode shows that for a positive potential difference the current increases rapidly with an increase in potential difference while for a negative potential difference the current remains negligible and does not increase as the potential difference becomes larger. | The IV graph for a light dependent resistor shows that at a high light intensity the current increases rapidly with the potential difference whereas at a low light intensity the current increases slowly with the potential difference. |
References
Edexcel
- I-V graphs, page 187, GCSE Combined Science; The Revision Guide, CGP, Edexcel
- I-V graphs, page 74, GCSE Physics; The Revision Guide, CGP, Edexcel
- I-V graphs, pages 227-229, GCSE Physics, CGP, Edexcel
- I-V graphs; diodes, page 229, GCSE Physics, CGP, Edexcel
- I-V graphs; filament lamps, page 228, GCSE Physics, CGP, Edexcel
- I-V graphs; fixed resistors, page 228, GCSE Physics, CGP, Edexcel
- I-V graphs; LDRs, page 229, GCSE Physics, CGP, Edexcel
- I-V graphs; thermistors, page 229, GCSE Physics, CGP, Edexcel