Series and Parallel Circuits

 How to Simplify to Find Total Resistance, Current and Voltage 


Series Circuits -  Series Circuits are the simplest to work with. • Here we have three resistors of different resistances. They share a single connection point. When added together the total resistance is (R1+R2+R3+R4) -Ohms.

                           series connection
           
series circuit

   

 Calculating Total Resistance of a Series Circuit


As the resistors are connected together in series the same current passes through each resistor in the chain and the total resistance, RT of the circuit must be equal to the sum of all the individual resistors added together
                      
Solving the above equation for total resistance (instead of the reciprocal of total resistance), we can invert (reciprocate) both sides of the equation:

Parallel Circuits - A parallel circuit is shown here and it has TWO common connection points with another component. In this case another resistor. We cannot add the values of each resistor together like we can in the previous series circuit. 
          parallel circuit
      

  Calculating Total Resistance of a Parallel Circuit

 Two methods can be used to calculate the total resistance of the parallel circuit. They are the Product Over Sum equation or the Reciprocal Formula. 

                 

The same basic form of equation works for any number of resistors connected together in parallel, just add as many 1/R terms on the denominator of the fraction as needed to accommodate all parallel resistors in the circuit.