⒈星形变换为三角形：R12 = r1 + r2 + r1·r2 / r3=r1*r2(1/r1+1/r2+1/r3)；R23 = r2 + r3 + r2*r3 / r1=r2*r3(1/r1+1/r2+1/r3)；R13 = r1 + r3 + r1·r3 / r2=r1*r3(1/r1+1/r2+1/r3)；写成电导的方式就是 G12=(g1*g2)/(g1+g2+g3)G23=(g2*g3)/(g1+g2+...