Memorise Delta – Y Transformation Formulas

Memorising the transformation formulas is one of the most difficult tasks a student may find, however this page might help you discover some simple patterns which might make it easier to remember the formula. Sometimes it is easier to see this pattern if you visualise both networks superimposed.

For delta to Y transformation formulas, the denominator part remains the same in all three formulas. Notice the positions of the known values in one network, with the unknown you need to find in the other. If you need to find R4, then it is the resistors on either side of it (R2 and R3) in the numerator part of the formula. The same pattern follows for the other two formulas as well.

For Y to delta transformation formulas, the numerator part remains the same in all three formulas. The calculator page shows how to find this part. In the denominator, we always use the resistor on the opposite side of the one we are trying to calculate. Therefore, the formula to find R1 contains the resistor on the opposite side of the network, which is R4. It is a simple pattern that once understood can help to memorise these long formulas.

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