Investigate the I−V characteristics of a variety of circuit elements including a filament lamp, a resistor and a diode at constant temperature.
Set up circuits with different sets of equipment to investigate how the current changes as with the potential difference.
There are three parts to this investigation:
• characteristics of a lamp
• characteristics of a resistor
• characteristics of a diode.
1. Record the current through each component for different values of potential difference.
This method uses a variable resistor to vary the potential difference, although a variable power supply may be used instead.
2. Plot a graph of current against potential difference.
The shape of the line/ curve of best fit indicates the characteristics of the component.
Note: The resistance at any point on the graph is the inverse of the gradient of a line from that point to the origin.