You have learned the three types of resistors, now you can investigate circuit components and identify which components act as which type of resistor.

Doing the experiment

1. Set up the circuit as shown in the diagram. Use a filament lamp, a diode or a resistor at a fixed temperature as the component.
2. Use the variable resistor to change the current through the circuit. For each current, record the current and potential difference.
3. Swap over the wires to the battery and repeat this experiment again. The ammeter will display a negative current and because the potential difference is in the opposite direction, you should record it as a negative value.
4. Repeat the experiment with your other components.

5. Plot an I-V graph for each of the components and identify which type of resistor they are: are they ohmic, non-ohmic or a diode?