def test_one_wire_capacitance_shield():
rw = 0.5e-3
rs = 4e-3
er = 5.2
wires = [Wire(0, 0, rw)]
ref = Shield(rs)
cable = mtl.WireMtl(wires, ref, er)
C = cable.capacitance()
expected = coax.capacitance(rw, rs, er)
assert C == approx(expected, rel=0.001, abs=1e-14)
def test_two_wire_capacitance_shield():
# Paul MTL P5.11
rw = 0.1905e-3
s = 4 * rw
rs = 4 * rw
wires = [Wire(-0.5 * s, 0, rw), Wire(0.5 * s, 0, rw)]
ref = Shield(rs)
pair = mtl.WireMtl(wires, ref)
C = pair.capacitance()
expected = np.array([[52.8, -10.73], [-10.73, 52.8]]) * 1e-12
assert C == approx(expected, rel=0.001, abs=1e-14)
def test_two_wire_inductance_shield():
# Paul MTL P5.10
rw = 0.1905e-3
s = 4 * rw
rs = 4 * rw
wires = [Wire(-0.5 * s, 0, rw), Wire(0.5 * s, 0, rw)]
ref = Shield(rs)
pair = mtl.WireMtl(wires, ref)
L = pair.inductance()
expected = np.array([[0.2197, 0.0446], [0.0446, 0.2197]]) * 1e-6
assert L == approx(expected, rel=0.001)
def test_shield_contains_overlap():
a = Wire(0.6, 0, 0.5)
s = Shield(1.0)
assert not s.contains(a)
def test_shield_contains_outside():
a = Wire(2.0, 0, 0.5)
s = Shield(1.0)
assert not s.contains(a)
def test_shield_contains_wire_on_edge():
a = Wire(0, 0.5, 0.5)
s = Shield(1.0)
assert s.contains(a)
def test_shield_contains_wire_larger():
a = Wire(0, 0, 1.5)
s = Shield(1.0)
assert not s.contains(a)
def test_shield_contains():
a = Wire(0, 0.0, 0.5)
s = Shield(1.0)
assert s.contains(a)
def test_shield_radius_zero():
with pytest.raises(ValueError):
Shield(0)