Complex circuits cannot be reduced to a single resister and contain components that are neither a series nor a parallel. In this type of circuit, resistors are connected in a complicated manner.
Complex circuits contain more than one source of electromotive force or pure voltage source. They cannot be solved by using series and parallel combinations.
Gustav Kirchhoff developed two laws that are used in solving complex circuits. Kirchhoff's first law states that the total current entering a node is equal to the total current exiting the node. His second law states that the total voltage in a closed loop is equal to the sum of all the voltage in the same loop. The first law is known as the conservation of charge, and the second is known as the conservation of energy.
Ohm's law is an equation used in the study of electric circuits. The equation states that the electric potential difference between two points on a circuit is equal to the product of the current between those two points and the total resistance of all electrical devices present between those two points. Ohm's law cannot be applied to complex circuits due to the inability of the circuits to be simplified.