Editing Y-Δ transform (section)

===Equations for the transformation from Δ to Y===<!--This section is linked from [[Template:Network analysis navigation]]. Changing this heading will break the template unless updated there also.-->
The general idea is to compute the impedance <math>R_\text{Y}</math> at a terminal node of the Y circuit with impedances <math>R'</math>, <math>R''</math> to adjacent nodes in the Δ circuit by

:<math>R_\text{Y} = \frac{R'R''}{\sum R_\Delta}</math>

where <math>R_\Delta</math> are all impedances in the Δ circuit. This yields the specific formula

:<math>\begin{align}
  R_1 &= \frac{R_\text{b}R_\text{c}}{R_\text{a} + R_\text{b} + R_\text{c}} \\[3pt]
  R_2 &= \frac{R_\text{a}R_\text{c}}{R_\text{a} + R_\text{b} + R_\text{c}} \\[3pt]
  R_3 &= \frac{R_\text{a}R_\text{b}}{R_\text{a} + R_\text{b} + R_\text{c}}
\end{align}</math>