def test_open_or_series_check(self):
with self.assertRaises(ValueError):
net = core._Network([
core.R(0, 1, 'Z'),
core.C(1, 2, 'Z'),
core.J(2, 3, 'Z'),
])
def test_connectivity_check_single_element_not_connected(self):
with self.assertRaises(ValueError):
net = core._Network([
core.R(0, 1, 'Z'),
core.C(1, 2, 'Z'),
core.J(3, 4, 'Z'),
])
def test_transfer_wheatstone_all_equal(self):
'''
Case where all resistors of the bridge are equal, and
there is potential for these lines:
A_lattice = (Ya + Yb)*(Yd + Yc)/(Ya*Yd-Yb*Yc)
B_lattice = (Ya + Yb + Yc + Yd)/(Ya*Yd-Yb*Yc)
to raise an error.
Note: I made sure with a break-point that this code
actually calls those two lines.
'''
# Compute the bridge transfer function
net = core._Network([
core.R(0, 1, 'R_3'),
core.R(1, 2, 'R_x'),
core.R(2, 3, 'R_2'),
core.R(3, 0, 'R_1'),
])
transfer = net.transfer(0, 2, 3, 1)
# Define some numerical values
# for the bridge resistors
test_parameters = {
'R_1': 1,
'R_2': 1,
'R_3': 1,
'R_x': 1,
}
# We just run this to check wether it raises an error
transfer.evalf(subs=test_parameters)
def test_transfer_square_symmetrical_lattice(self):
'''
Square symmetrical lattice
'''
# Compute the transfer function
left_minus = 0
left_plus = 1
right_minus = 2
right_plus = 3
net = core._Network([
core.R(left_minus, left_plus, 'Zs'),
core.R(right_minus, right_plus, 'Zl'),
core.Admittance(left_minus, right_plus, 0),
core.Admittance(right_minus, left_plus, 0),
core.R(left_minus, right_minus, 'Za'),
core.R(right_plus, left_plus, 'Za')
])
transfer = net.transfer(left_minus, left_plus, right_minus, right_plus)
# What the tranfer function should be
def transfer_theory(Zs, Zl, Za):
return Zl / (2 * Za + Zl)
# Define some numerical values
# for the resistors
test_parameters = {
'Zs': 1,
'Zl': 2,
'Za': 3,
}
self.assertRelativelyClose(transfer.evalf(subs=test_parameters),
transfer_theory(**test_parameters))
def test_transfer_wheatstone(self):
'''
Wheatstone bridge, see:
https://en.wikipedia.org/wiki/Wheatstone_bridge
Note that the correct definitions of the voltages V_G and V_S can be found here:
http://www.ece.lsu.edu/ee4770/1999/lsli04.4up.pdf
'''
# Compute the bridge transfer function
net = core._Network([
core.R(0, 1, 'R_3'),
core.R(1, 2, 'R_x'),
core.R(2, 3, 'R_2'),
core.R(3, 0, 'R_1'),
])
transfer = net.transfer(0, 2, 3, 1)
# What the tranfer function should be
def transfer_theory(R_1, R_2, R_3, R_x):
return R_2 / (R_1 + R_2) - R_x / (R_x + R_3)
# Define some numerical values
# for the bridge resistors
test_parameters = {
'R_1': 1,
'R_2': 2,
'R_3': 3,
'R_x': 4,
}
self.assertRelativelyClose(transfer.evalf(subs=test_parameters),
transfer_theory(**test_parameters))
def test_transfer_voltage_divider(self):
'''
Voltage divider, see:
https://en.wikipedia.org/wiki/Voltage_divider
We add an extra resistor between Vin and ground
'''
# Compute the bridge transfer function
net = core._Network([
core.R(0, 1, 'Z2'),
core.R(1, 2, 'Z1'),
core.R(2, 0, 'Zg'),
])
transfer = net.transfer(0, 2, 0, 1)
# What the tranfer function should be
def transfer_theory(Z1, Z2, Zg):
return Z2 / (Z1 + Z2)
# Define some numerical values
# for the resistors
test_parameters = {'Z1': 1, 'Z2': 2, 'Zg': 3}
self.assertRelativelyClose(transfer.evalf(subs=test_parameters),
transfer_theory(**test_parameters))
def test_connectivity_check_subcircuit_not_connected(self):
with self.assertRaises(ValueError):
net = core._Network([
core.R(0, 1, "Z"),
core.C(1, 2, "Z"),
core.J(3, 4, "Z"),
core.J(3, 4, "Z"),
core.J(4, 5, "Z"),
])
def test_transfer_left_right_port_indentical_inverted(self):
'''
Trivial cases
'''
net = core._Network([core.R(0, 1, 'Z2')])
self.assertEqual(net.transfer(0, 1, 1, 0), -1)
def test_transfer_left_right_port_indentical_inverted(self):
"""
Trivial cases
"""
net = core._Network([core.R(0, 1, "Z2")])
self.assertEqual(net.transfer(0, 1, 1, 0), -1)
