任意阻抗的功率计算： Pz=UIcoso =PZcoso =PR Qz=UIsing =PIZIsing =PX =P(XL+Xc)=QL+Qc S=P2+0=PR+X=IZ 相似三角形 R任意阻抗的功率计算： u i Z + - PZ =UIcos =I 2 |Z|cos =I 2R QZ =UIsin =I 2 |Z|sin =I 2X ＝I 2 (XL＋XC)=QL＋QC S P Q I R X I Z 2 2 2 2 2 2 = + = + =  S P Q  Z R 相似三角形 X