Series and Parallel Circuits

• The current at any point in a series circuit is the same
• The current splits at each branch in a parallel circuit so the total current is always greater than the current in one branch
• If you combine resistors in series: $R_{Total}\ =$$\ R_1+$$\ R_2\$
• The combined resistance of 2 resistors in parallel is less than that of either resistor by itself and the current in the two resistors in greater in the source than in the individual resistors and is equal to the sum of the currents in all the resistors connected in parallel.
• The advantages of putting lamps in parallel are:

  • If one lamp breaks, the other still works
  • Each lamp gets maximum PD
• In series: PD across the supply = PD across all the components combined
• In parallel: Current across the source = sum of currents in the separate branches
• If you combine resistors in parallel:

  Rtotal = 1 / ((1/R1) + (1/R2))