https://www.circuitlab.com/circuit/62vd4a/whitening-non-inverting/
Sean Leavey
"""
import numpy as np
from zero import Circuit
from zero.analysis import AcSignalAnalysis
if __name__ == "__main__":
# 1000 frequencies between 1 Hz to 1 MHz.
frequencies = np.logspace(0, 6, 1000)
# Create circuit object.
circuit = Circuit()
# Add components.
circuit.add_capacitor(value="10u", node1="gnd", node2="n1")
circuit.add_resistor(value="430", node1="n1", node2="nm")
circuit.add_resistor(value="43k", node1="nm", node2="nout")
circuit.add_capacitor(value="47p", node1="nm", node2="nout")
circuit.add_library_opamp(model="LT1124",
node1="gnd",
node2="nm",
node3="nout")
# Solve circuit.
analysis = AcSignalAnalysis(circuit=circuit)
solution = analysis.calculate(frequencies=frequencies,
input_type="current",
class CircuitTestCase(TestCase):
"""Circuit tests"""
def setUp(self):
self.reset()
def reset(self):
"""Reset circuit"""
self.circuit = Circuit()
def test_add_component(self):
"""Test add component to circuit"""
r = Resistor(name="r1", value=10e3, node1="n1", node2="n2")
c = Capacitor(name="c1", value="10u", node1="n1", node2="n2")
l = Inductor(name="l1", value="1u", node1="n1", node2="n2")
self.circuit.add_component(r)
self.assertCountEqual(self.circuit.components, [r])
self.assertCountEqual(self.circuit.non_gnd_nodes,
[Node("n1"), Node("n2")])
self.assertEqual(self.circuit.n_components, 1)
self.assertEqual(self.circuit.n_nodes, 2)
self.circuit.add_component(c)
self.assertCountEqual(self.circuit.components, [r, c])
self.assertCountEqual(self.circuit.non_gnd_nodes,
[Node("n1"), Node("n2")])
self.assertEqual(self.circuit.n_components, 2)
self.assertEqual(self.circuit.n_nodes, 2)
self.circuit.add_component(l)
self.assertCountEqual(self.circuit.components, [r, c, l])
self.assertCountEqual(self.circuit.non_gnd_nodes,
[Node("n1"), Node("n2")])
self.assertEqual(self.circuit.n_components, 3)
self.assertEqual(self.circuit.n_nodes, 2)
def test_add_component_without_name(self):
"""Test add component without name to circuit"""
r = Resistor(value=10e3, node1="n1", node2="n2")
c = Capacitor(value="10u", node1="n1", node2="n2")
l = Inductor(value="1u", node1="n1", node2="n2")
op = OpAmp(model="OP00", node1="n1", node2="n2", node3="n3")
self.assertEqual(r.name, None)
self.circuit.add_component(r)
self.assertEqual(r.name, "r1")
self.assertEqual(c.name, None)
self.circuit.add_component(c)
self.assertEqual(c.name, "c1")
self.assertEqual(l.name, None)
self.circuit.add_component(l)
self.assertEqual(l.name, "l1")
self.assertEqual(op.name, None)
self.circuit.add_component(op)
self.assertEqual(op.name, "op1")
def test_remove_component(self):
"""Test remove component from circuit"""
r = Resistor(name="r1", value=10e3, node1="n1", node2="n2")
c = Capacitor(name="c1", value="10u", node1="n1", node2="n2")
self.circuit.add_component(r)
self.circuit.add_component(c)
self.assertCountEqual(self.circuit.components, [r, c])
self.assertCountEqual(self.circuit.non_gnd_nodes,
[Node("n1"), Node("n2")])
self.assertEqual(self.circuit.n_components, 2)
self.assertEqual(self.circuit.n_nodes, 2)
self.circuit.remove_component(r)
self.assertEqual(self.circuit.components, [c])
self.assertCountEqual(self.circuit.non_gnd_nodes,
[Node("n1"), Node("n2")])
self.assertEqual(self.circuit.n_components, 1)
self.assertEqual(self.circuit.n_nodes, 2)
self.circuit.remove_component(c)
self.assertEqual(self.circuit.components, [])
self.assertEqual(self.circuit.non_gnd_nodes, [])
self.assertEqual(self.circuit.n_components, 0)
self.assertEqual(self.circuit.n_nodes, 0)
def test_remove_component_by_name(self):
"""Test remove component from circuit by name"""
r = Resistor(name="r1", value=10e3, node1="n1", node2="n2")
c = Capacitor(name="c1", value="10u", node1="n1", node2="n2")
self.circuit.add_component(r)
self.circuit.add_component(c)
self.circuit.remove_component("r1")
self.circuit.remove_component("c1")
self.assertEqual(self.circuit.components, [])
self.assertCountEqual(self.circuit.non_gnd_nodes, [])
self.assertEqual(self.circuit.n_components, 0)
self.assertEqual(self.circuit.n_nodes, 0)
def test_cannot_add_component_with_invalid_name(self):
"""Test components with invalid names cannot be added to circuit"""
# name "all" is invalid
r = Resistor(name="all", value=1e3, node1="n1", node2="n2")
self.assertRaisesRegex(ValueError, r"component name 'all' is reserved",
self.circuit.add_component, r)
# name "sum" is invalid
c = Capacitor(name="sum", value=1e3, node1="n1", node2="n2")
self.assertRaisesRegex(ValueError, r"component name 'sum' is reserved",
self.circuit.add_component, c)
def test_cannot_add_duplicate_component(self):
"""Test component already present in circuit cannot be added again"""
# duplicate component
r1 = Resistor(name="r1", value=1e3, node1="n1", node2="n2")
r2 = Resistor(name="r1", value=2e5, node1="n3", node2="n4")
self.circuit.add_component(r1)
self.assertRaisesRegex(ValueError,
r"element with name 'r1' already in circuit",
self.circuit.add_component, r2)
self.reset()
# different component with same name
r1 = Resistor(name="r1", value=1e3, node1="n1", node2="n2")
op1 = OpAmp(name="r1",
model="OP00",
node1="n3",
node2="n4",
node3="n5")
self.circuit.add_component(r1)
self.assertRaisesRegex(ValueError,
r"element with name 'r1' already in circuit",
self.circuit.add_component, op1)
def test_cannot_add_component_with_same_name_as_node(self):
"""Test component with same name as existing node cannot be added"""
# first component
r1 = Resistor(name="r1", value=1e3, node1="n1", node2="n2")
# second component, with same name as one of first component's nodes
r2 = Resistor(name="n1", value=2e5, node1="n3", node2="r4")
self.circuit.add_component(r1)
self.assertRaisesRegex(ValueError,
r"element with name 'n1' already in circuit",
self.circuit.add_component, r2)
self.reset()
# different component with same name
r1 = Resistor(name="r1", value=1e3, node1="n1", node2="n2")
op1 = OpAmp(name="n1",
model="OP00",
node1="n2",
node2="n4",
node3="n5")
self.circuit.add_component(r1)
self.assertRaisesRegex(ValueError,
r"element with name 'n1' already in circuit",
self.circuit.add_component, op1)
def test_cannot_add_node_with_same_name_as_component(self):
"""Test node with same name as existing component cannot be added"""
# first component
r1 = Resistor(name="r1", value=1e3, node1="n1", node2="n2")
# second component, with node with same name as first component
r2 = Resistor(name="r2", value=2e5, node1="n3", node2="r1")
self.circuit.add_component(r1)
self.assertRaisesRegex(
ValueError, r"node 'r1' is the same as existing circuit component",
self.circuit.add_component, r2)
self.reset()
# different component with same name
r1 = Resistor(name="r1", value=1e3, node1="n1", node2="n2")
op1 = OpAmp(name="op1",
model="OP00",
node1="r1",
node2="n4",
node3="n5")
self.circuit.add_component(r1)
self.assertRaisesRegex(
ValueError, r"node 'r1' is the same as existing circuit component",
self.circuit.add_component, op1)
class MutualInductanceTestCase(TestCase):
"""Mutual inductance tests"""
def setUp(self):
# Triple transformer, winding ratio 1:3:3.
self.circuit = Circuit()
self.circuit.add_resistor(value="1k", node1="n1", node2="n2")
self.circuit.add_inductor(value="1m",
node1="n2",
node2="gnd",
name="l1")
self.circuit.add_inductor(value="9m",
node1="n3",
node2="gnd",
name="l2")
self.circuit.add_inductor(value="9m",
node1="n4",
node2="gnd",
name="l3")
self.circuit.add_resistor(value="1k", node1="n3", node2="gnd")
self.circuit.add_resistor(value="1k", node1="n4", node2="gnd")
def test_matrix_impedance_elements(self):
"""Test impedance matrix elements are the same for both inductors"""
# Add mutual inductance between all three coils.
self.circuit.set_inductor_coupling("l1", "l2")
self.circuit.set_inductor_coupling("l2", "l3")
self.circuit.set_inductor_coupling("l1", "l3")
# Get circuit matrix, with prescaling switched off so we can directly compare values.
analysis = MockMutualInductanceAcSignalAnalysis(circuit=self.circuit)
# Add circuit input.
analysis.set_input(input_type="voltage", node="n1")
# Get inductors.
l1 = analysis.get_component_from_current_circuit("l1")
l2 = analysis.get_component_from_current_circuit("l2")
l3 = analysis.get_component_from_current_circuit("l3")
# Get inductor current indices.
l1_index = analysis.component_matrix_index(l1)
l2_index = analysis.component_matrix_index(l2)
l3_index = analysis.component_matrix_index(l3)
# Check at various frequency decades.
for frequency in np.logspace(-3, 6, 10):
with self.subTest(
msg="Test impedance matrix elements for coupled inductors",
frequency=frequency):
# Get matrix for this frequency.
matrix = analysis.circuit_matrix(frequency)
# There should be a term proportional to the current of each paired inductor on the
# opposite inductor's equation.
self.assertEqual(matrix[l1_index, l2_index],
l1.impedance_from(l2, frequency))
self.assertEqual(matrix[l1_index, l2_index], matrix[l2_index,
l1_index])
self.assertEqual(matrix[l1_index, l3_index],
l1.impedance_from(l3, frequency))
self.assertEqual(matrix[l1_index, l3_index], matrix[l3_index,
l1_index])
self.assertEqual(matrix[l2_index, l3_index],
l2.impedance_from(l3, frequency))
self.assertEqual(matrix[l2_index, l3_index], matrix[l3_index,
l2_index])