2.2.3 Comparing Series & Parallel Circuits

• Series Circuits

  • Components are connected end-to-end, forming a single path for current
  • Current flows through each component in turn
• Parallel Circuits

  • Components are connected across the same two points, forming multiple paths for current
  • Current can flow through multiple branches simultaneously
• Key Differences

  • Current
  • Voltage
  • Resistance
  • Power
• In Series Circuits


  The same current flows through all components
• In Parallel Circuits

  The total current is divided among the different branches
• Voltage in Series

  The total voltage across the circuit is the sum of the voltages across each component
• Voltage in Parallel

  The voltage across each component is the same and equals the source voltage
• Resistance in Series

  The total resistance is the sum of the individual resistances
• Resistance in Parallel

  The total resistance is found using the reciprocal formula
• Power in Series

  Power is shared among components
• Power in Parallel

  Each component receives the full source voltage
• Advantages of Series Circuits

  • Simple to design and understand
  • Components are connected in a straightforward manner
• Disadvantages of Series Circuits

  • If one component fails, the entire circuit is interrupted
  • The total resistance increases with additional resistors
• Advantages of Parallel Circuits

  • If one branch fails, the rest of the circuit continues to operate
  • The total resistance decreases with additional branches
• Disadvantages of Parallel Circuits

  • More complex to design and analyze
  • Requires careful consideration of current distribution and power ratings
• Series Circuits


  • A string of Christmas lights where a single blown bulb affects the entire string
  • Used in devices where the failure of one component affects the whole system
• Parallel Circuits


  • Household electrical systems where each appliance operates independently
  • Used in home wiring systems to ensure independent operation