4.4阻抗与导纳 例 己知:R=152,L=0.3mH,C=0.2μF, u=5√2c0s(@t+60),f=3x104Hz 求i,ur,L,uc zwouRfarne 相量模型 R 代入己知条件,得: Z=15+j(56.52-26.5)=33.54∠63.4 U u=5V2cos(ot+60°)→0=5∠60 →i=U/Z=0.149∠-3.4°A →i=0.149W2cos(ot-3.4)A例. L C R u uL uC i + - + - + - 已知:R=15, L=0.3mH, C=0.2F, 5 2 c o s ( 6 0 ) , 3 1 0 H z . 4 u = t + f = 求 i, uR , uL , uC . 相量模型 . I j L R + - + - + - . U U L . U C . jωC 1 4.4 阻抗与导纳 1 = + 2 1 2 Z R j R L fL C j fC − − = + Z j =15+ 56.5 5 ( 2 26. 33.54 ) 63.4 − = 代入已知条件,得: u t U 5 2 cos 60 5 60 ( ) = + → = ( ) / 0.149 3.4 Ao A 0.149 2 c s 3.4 I U i t Z → = = → = − −