Editing Network analysis (electrical circuits) (section)

==Nodal analysis==
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Nodal analysis uses the concept of a node voltage and considers the node voltages to be the unknown variables.{{r|"Circuit Analysis, Chen"|p=2-8 - 2-9}} For all nodes, except a chosen reference node, the node voltage is defined as the voltage drop from the node to the reference node. Therefore, there are N-1 node voltages for a circuit with N nodes.{{r|"Circuit Analysis, Chen"|p=2-10}}

In principle, nodal analysis uses [[Kirchhoff's current law]] (KCL) at N-1 nodes to get N-1 independent equations. Since equations generated with KCL are in terms of currents going in and out of nodes, these currents, if their values are not known, need to be represented by the unknown variables (node voltages). For some elements (such as resistors and capacitors) getting the element currents in terms of node voltages is trivial.

For some common elements where this is not possible, specialized methods are developed. For example, a concept called supernode is used for circuits with independent voltage sources.{{r|"Circuit Analysis, Chen"|p=2-12 - 2-13}}

# Label all '''nodes''' in the circuit. Arbitrarily select any node as reference.
# Define a voltage variable from every remaining node to the reference. These voltage variables must be defined as voltage rises with respect to the reference node.
# Write a KCL equation for every node except the reference.
# Solve the resulting system of equations.