series and parallel

• In any circuit energy must be conserved. This means it cannot be created or destroyed.
• • Kirchhoff's second law
  • The total electromotive force in a series circuit is equal to the sum of potential differences across each component.
  • Energy is put into the circuit by the voltage at the cell.
  • When current flows through a component there is a voltage drop. 
  • The total of all the voltage drops across every component in the circuit must be equal to the amount of voltage put in by the cell.
• The total resistance of resistors in parallel is always less than the smallest resistor in the parallel network.
• • Resistors in series
  • The total resistance is the sum of each individual resistor.
• Resistors in parallel

  • The reciprocal total resistance, 1/ total resistance​, is the sum of the reciprocal resistances in the network.
• resistors in parallel will reduce resistance
• resistors in series will increase resistance
• putting two of the same resistors in parallel will halve the resistance
• the total resistance of a parallel is less than the resistance of the smallest resistor