An electric circuit based on three concepts, namely, node, branch and loop. As per definition, an electric network is a combination of interconnected circuit elements.

     *The point through which an circuit element is connected to the circuit is called node. It is better to say, node is a point where, terminal of two or more circuit elements are connected together. Node is a junction point in the circuit.

      *The elements connected to an electric circuit is generally two terminal element. When, one circuit element is connected to the circuit, it connects itself through both of its terminals, to be a part of a closed path.

      * An electric circuit has numbers of nodes. If one starts from one node and after going through a set of nodes returns to same starting node without crossing any of the intermediate node twice, he has travels through one loop of the circuit.