Required practical 4

  1. Connect a power pack to a component (fixed resistor, filament lamp, or diode) in series with an ammeter and a variable resistor.

  2. Connect a voltmeter in parallel across the component.

  3. First use the voltmeter to read potential difference and then record them.

  4. Then use the ammeter to read current through the resistor and also record them.

  5. Do it several times to record the readings

  6. Reverse the connections to the power supply to take readings for negative potential differences and current

  7. Plot potential difference on the x-axis against current on the y-axis.


  • The temperature of resistor needs to be constant else the graph would take a different shape.

  • To prevent this, do not leave the circuit connected for too long.