U=ZI=RI+j(XL-XC/=RI+JXI=UR+UX JUEVUR +UX 电压三角形 U=Ucos 0 Ur=Usin 6 R 感性XL>Xc 容性XL<XCUR UX U ZI RI I RI I  =  =  +  =  +  =  +  j(XL -XC ) jX |sin | cos | | 2 2 X Z R Z R X U U U U U U U   = = = + 电压三角形： UL  UX  UC  UR  U  感性XL>XC UL  UX  UC  UR  U  容性XL<XC I  I  Z Z