Prof. Rich Kozick
Steps in the Node-Voltage Method
- Identify the ne essential nodes
(where three or more circuit elements join).
- Choose one node as the reference (usually the node with the most
branches), and label the rest
of the essential nodes with 1, 2, ..., (ne-1).
- Define "node voltages" vk, for
k = 1, 2, ..., (ne-1),
as the voltage rise from the reference node to each
- Write KCL at each nonreference node, with positive current
leaving each branch.
- Solve the resulting set of (ne-1)
simultaneous linear equations.
- If desired, other voltages and currents in the circuit may
be obtained from the node voltages.
Dealing with voltage sources:
- Avoid writing equations that require the current
through a voltage source.
- Voltage sources directly relate node voltages,
and sometimes reduce the number of simultaneous equations.
- Supernodes allow you to write KCL at a larger node
(involving more than one node voltage).
Then voltage sources "inside" the supernode
provide another equation to relate the node voltages.