Electrical Circuits

• Kirchhoff's second law states that the sum of all of the potential difference is equal to the sum emf of the circuit
• Total resistance in a series circuit:

  $Rt=$$R1+$$R2+$$R3$
• Total resistance in a parallel circuit:

  $1/Rt=$$1/R1 +$$1/R2 +$$1/R3$
• True or false: Adding a resistor to a circuit in parallel will always reduce the total resistance

  True, total resistance drops the more paths there are for the current to take.
• Current in a series circuit is the same throughout all components
• current in a parallel circuit is not the same, each branch of the circuit has difference currents, the higher resistance of the branch, the lower the current flow through the branch will be
• Internal resistance is the resistance within a power source
• Lost volts are the difference in voltage between the supplied and the amount available to the circuit, they are lost due to the internal resistance of the source.
• Purpose of a potential divider is to provide variable potential difference to the components in the circuit