更新时间2019-01-15 10:28:15
z1 = 30//(-j30) = -j900/(30-j30) = 900∠-90°/(30√2∠-45°) = 15√2∠-45° ;
戴维宁等效电压 u = is * z1 = 4∠90° * 15√2∠-45° = 60√2∠45°;
戴维宁等效电阻 z = z1 - j30
= 15√2[ cos(-45°) + jsin(-45°) ] - j30 = 15√2 * 1/√2 - 15√2 * j/√2 - j30 = 15 - j45;
ZL = 15 + j45 = 15√10∠arctan3 时,能获得最大功率;
i = u/( ZL + z ) = 60√2∠45°/( 15 - j45 + 15 + j45 ) = 2√2∠45°;
Pmzx = (2√2)^2 * 15√10 = 120√10 w 。