Investigate how p.d affects current in resistor

• Potential difference is same as


  Voltage
• What does variable resistor do?


  Vary p.d across resistor and bulb
• What is independent variable 


  Potential difference
• What is dependent variable 


  Current
• What is control?


  Variable
• Conclusion

  As I increase p.d current increases linearly
• Low resistance =


  Low line
• High resistance =


  Higher line
• What does resistor occur between?


  The collisions of moving electrons and the positive ions in the wire
• Why does the filament get hotter in the bulb, what do you increase

  Potential difference
• The filament gets hotter and the positive ions vibrate more...


  So electrons move increasing resistance
• Semi conductor only happens when conditions are
• Current flows if diode is right way

  No current if diode wrong
• If diode is connected wrong way, what happens to resistance and current,?


  Massive resistance so no current

  
• Diode is right way so whar happens to resistance and no current?


  Low resistance and current fasts

  
• Sem conductor 


  1)diode 2)LDRA(Light dependent resitor) 3),thermistor
• 2)LDR conclusion

  As light intensity increases the resistance decreases non-linearly(light energy increase number of delocalsied electorns so resitance decrease)
• LDR graph: 0 V = 0 V, 1 V = 10 V, 2 V = 20 V

  
• 3)thermistor conclusion 


  As tempature increases resistance decreases non-linearly
• Equiptment to investigate

  • Components to test (e.g. a filament lamp, a fixed resistor and a diode).
  • Connecting leads,
  • A power pack,
  • An ammeter
  • A voltmeter,
  • A variable resistor, .
• Step 1: Connect your circuit element t, all in series.

  Step 2: Connect the voltmeter in parallel with the element.
• Step 3: Make sure the variable resistor is on its highest setting. Step 4: Switch on the power pack and record the current and potential difference in a table.
• Step 5: Switch off power pack ( prevents the circuit overheating).

  Step 6: Lower the resistance of the variable resistor and repeat steps 4 and 5.
• Step 7: Keep lowering the resistance until you have at least 6 pairs of results Step 8: Plot a graph of current against potential difference using the results in your table
• Why does filament lamp look like that?

  It gets hotter as current increases, which increases its resistance.

  
• Why is fixed resistor straight line?

  fixed resistor obeys Ohm's law, so current is directly proportional to potential difference