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. A network may or may not provide closed path to the electric current to flow. But, an electrical circuit may be a combination of one or more networks which gives closed path to the electric current. That means, when one or more networks are interconnected together to complete one or more paths to the current, an electric circuit is formed.
An electric circuit does have three conceptual things as mentioned below.
Nodes of Electric Circuit
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.
In the above circuit nodes are indicated by bullets.
NB:- If three is no element between two or more connected adjacent nodes, these nodes can be recombined as a single node.
Finally, the circuit can be redrawn as,
Branch of Electric 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.
Any of the circuit elements, when connected to the circuit, it is definitely connected between two nodes of the circuit. When an element exists between two nodes, the path from one node to another through this element is called branch of the circuit.
The branch of an electric circuit can be defined more precisely, as the portion of the circuit between two nodes which can deliver or absorb energy. As per this definition, the short circuit between two nodes is not referred as branch of electric circuit.
Loops in Electric Circuit
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.