DC Circuits

$$ I_2 = {R_1}/{(R_1 + R_2)} I $$

OR

$$ I_1 = {R_2}/{(R_1 + R_2)} I $$

Delta to Star Conversion:

E.g. $R_1 = {\text"Product of adjacent resistors in delta"}/{\text"Sum of all the resistors in delta"}$
$R_1 = {R_{12} R_{31}}/{R_{12} + R_{23} + R_{31}}$

Star to Delta Conversion:

$R = R_1 R_2 + R_2 R_3 + R_1 R_3$

E.g. $R_{12} = {R}/{R_3}$

Any resistance in equivalent delta = ${\text"Total resistance R in star"}/{\text"Opposite resistance in star"}$