def test_efield_2layer_2(): # Cheng Ex. 3-16 ri = 4e-3 er1, t1 = 3.2, (6.16e-3 - ri) er2, t2 = 2.6, (8.32e-3 - 6.16e-3) cc = CoaxCapacitor(ri, (er1, er2), (t1, t2)) R = np.array([ri, 0.999 * (ri + t1), 1.001 * (ri + t1), ri + t1 + t2]) E = cc.efield(R, Va=20e3) assert E == approx(np.array([6.25e6, 4.06e6, 5.00e6, 3.71e6]), rel=0.01)
def test_efield_2layer(): ri = 8e-3 er1, t1 = 6.0, 2e-3 er2, t2 = 3.0, 20e-3 cc = CoaxCapacitor(ri, (er1, er2), (t1, t2)) R = np.array([8e-3, 10e-3, 10.001e-3, 30e-3]) E = cc.efield(R, Va=12500) assert E == approx(np.array([0.6456e6, 0.5165e6, 1.033e6, 0.3443e6]), abs=1e3)
def test_efield(): ri = 0.5e-3 ro = 4.0e-3 N = 5 cc = CoaxCapacitor(ri, 5.2, ro - ri) X = np.linspace(ri, ro, N) Va = 10.0 expected = -Va / X / np.log(ri / ro) efield = cc.efield(X, Va=Va) assert efield == approx(expected)