def test_2layer_area():
er1, t1 = 5.0, 1e-3
er2, t2 = 1.0, 3e-3
A = 3.0
pp1 = ParallelPlates((er1, er2), (t1, t2))
pp2 = ParallelPlates((er1, er2), (t1, t2), area=A)
Va = 25.0
X = np.linspace(0, t1 + t2, 11)
assert pp1.capacitance() == approx(pp2.capacitance() / A)
assert pp1.efield(X, Va) == approx(pp2.efield(X, Va))
assert pp1.potential(X, Va) == approx(pp2.potential(X, Va))
def test_efield():
t = 1e-3
N = 5
pp = ParallelPlates(3.5, t)
X = np.linspace(0, t, N)
Va = 10.0
expected = -Va / t * np.ones(N)
efield = pp.efield(X, Va)
assert efield == approx(expected)
def test_efield_2layer():
er1, t1 = 5.0, 1e-3
er2, t2 = 1.0, 3e-3
pp = ParallelPlates((er1, er2), (t1, t2))
X = np.linspace(0, 4e-3, 5)
E = pp.efield(X, 200)
E1 = -12.5 / t1
E2 = -187.5 / t2
assert E == approx([E1, E1, E2, E2, E2])
def test_efield_pplate():
er1, t1 = 5.0, 1e-3
er2, t2 = 1.0, 3e-3
Va = 200
pp = ParallelPlates((er1, er2), (t1, t2))
X, dx = np.linspace(0, 4e-3, 21, retstep=True)
V = pp.potential(X, Va)
E = pp.efield(X, Va)
Ec = em.efield_1d(V, dx)
assert Ec[:5] == approx(E[:5])
# discontinuity at boundary [5]
assert Ec[6:] == approx(E[6:])
