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{{section howto|date=October 2022}}
{{main|nodal analysis}}
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
# Solve the resulting system of equations.
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In this method, the effect of each generator in turn is calculated. All the generators other than the one being considered are removed and either short-circuited in the case of voltage generators or open-circuited in the case of current generators. The total current through or the total voltage across a particular branch is then calculated by summing all the individual currents or voltages.
There is an underlying assumption to this method that the total current or voltage is a linear superposition of its parts. Therefore, the method cannot be used if non-linear components are present.<ref name="Circuit Analysis, Chen">Wai-Kai Chen, ''Circuit Analysis and Feedback Amplifier Theory'', p. 6-14, CRC Press, 2005 {{ISBN|1420037277}}.</ref> Superposition of powers cannot be used to find total power consumed by elements even in linear circuits. Power varies according to the square of total voltage or current and the square of the sum is not generally equal to the sum of the squares. Total power in an element can be found by applying superposition to the voltages and current independently and then calculating power from the total voltage and current.
==Choice of method==
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