⒈星形變換為三角形:
R12 = r1 *r2+ r2*r3 + r3·r1 / r3;
R23 =r1* r2 + r2*r3 + r3*r1 / r1;
R13 = r1 *r2+ r2*r3 + r3·r1 / r2;
⒉三角形變換星形:
r1 = (R12·R13) / (R12 + R23 + R13);
r2 = (R23·R12) / (R12 + R23 + R13);
r3 = (R13·R23) / (R12 + R23 + R13);
具體變換方法可以用基爾霍夫定律來變換。