lcapy.nodalanalysis.NodalAnalysis

class lcapy.nodalanalysis.NodalAnalysis(cct, node_prefix='')

Bases: object

This is for nodal analysis.

>>> from lcapy import Circuit, NodalAnalysis
>>> cct = Circuit('''
... V1 1 0 {u(t)}; down
... R1 1 2; right=2
... L1 2 3; down=2
... W1 0 3; right
... W 1 5; up
... W 2 6; up
... C1 5 6; right=2
...''')

To perform nodal analysis in the Laplace domain:

>>> na = NodalAnalysis(cct.laplace())

To display the equations found by applying KCL at each node:

>>> na.nodal_equations().pprint()

To display the system of equations (in matrix form) that needs to be solved:

>>> na.matrix_equations().pprint()

This only works for dc, ac, or laplace domains. For example,

>>> NodalAnalysis(cct.laplace()).matrix_equations().pprint()

Methods

__init__(cct[, node_prefix])	cct is a netlist node_prefix can be used to avoid ambiguity between component voltages and node voltages.
equations_dict()	Return dictionary of equations keyed by node name.
from_circuit(cct[, node_prefix])
matrix_equations([form, invert])	Return the equations in matrix form.
nodal_equations()	Return the equations found by applying KCL at each node.
pdb()	Enter the python debugger.
solve_laplace()	Determine the unknown voltages using Laplace transforms and return as a dict

Attributes

A	Return A matrix where A y = b.
b	Return b vector where A y = b.
nodes
unknowns	Return tuple of the unknown voltages
y	Return y vector where A y = b.

property A

Return A matrix where A y = b.

property b

Return b vector where A y = b.

equations_dict()

Return dictionary of equations keyed by node name.

matrix_equations(form='default', invert=False)

Return the equations in matrix form.

Forms can be:

‘default’ ‘A y = b’ ‘b = A y’ ‘Ainv b = y’ ‘y = Ainv b’

If invert is True, evaluate the matrix inverse.

nodal_equations()

Return the equations found by applying KCL at each node. This is a directory of equations keyed by the node name.

pdb()

Enter the python debugger.

solve_laplace()

Determine the unknown voltages using Laplace transforms and return as a dict

property unknowns

Return tuple of the unknown voltages

property y

Return y vector where A y = b.