There are 2 types of circuits.... Series and Parallel.

• Series Circuits
  • Are connected in a straight line, like a chain.
  • All current remains the same throughout the circuit.

    I_Total = I₁=I₂=I₃ etc...

  • There can be many different voltages in a series circuit, as a voltage drop appears across every resistor.
  • The total voltage in a series circuit is equal to the sum of all the individual voltage drops within the circuit.

    E_Total = E₁ + E₂ + E₃ + etc...

  • The total resistance in a series circuit is equal to the sum of all the individual resistances within the circuit.
  • The formula for Resistance in Series is:

    R_Total = R₁ + R₂ + R₃ + etc...

• Parallel Circuits
  • Are connected allowing multiple paths for current flow.
  • All voltage remains the same throughout the circuit.

    E_Total = E₁=E₂=E₃ etc...

  • There can be many different currents in a parallel circuit, as each leg has the same voltage, but can have a different resistance.
  • The total current in a parallel circuit is equal to the sum of all the individual currents on each leg of the circuit.
  • The formula for Current in Parallel is:

    I_RTotal = I_R1 + I_R2 + I_R3 + etc...

  • Resistance is found by reciprocating the sum of the reciprocals of the resistance of the individual branches
  • The formula for Resistance in Parallel is:

                       1

     -----------------------------------

     1       1        1       1        1

    ---- + ---- + ---- + ---- + ---- +

    R₁      R₂     R₃    R₄     R_X...

• Ohm's Law states that there is a relationship which exists between current, resistance, and voltage, such that E = I x R