Circuits and Resistance

• Circuits and Resistance


  • Length of wire affects resistance
  • Placing resistors in series or parallel affects resistance of whole circuit
• Adding Resistors in Series

  1. Find at least four identical resistors

  2. Build circuit with one resistor

  3. Measure potential difference of battery

  4. Measure current through circuit

  5. Calculate resistance using R=V/I

  6. Add another resistor in series

  7. Measure current and calculate resistance

  8. Repeat until all resistors added

  9. Plot graph of number of resistors vs total resistance
• Adding Resistors in Parallel

  1. Use same equipment as before

  2. Build initial circuit

  3. Measure total current through circuit and calculate resistance using R=V/I

  4. Add another resistor in parallel

  5. Measure total current and calculate resistance

  6. Repeat until all resistors added

  7. Plot graph of number of resistors vs total resistance
• Resistance Rules


  • Adding resistors in series increases total resistance
  • More resistors added, larger the resistance of whole circuit
  • Adding resistors in parallel increases total current, decreases total resistance
  • More resistors added, smaller the overall resistance