I-V characteristics

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.