1. Delta-Wye Conversions
What if resistors are neither in series nor in parallel?

2. Delta-Wye
Many circuits can be simplified using three-terminal equivalent networks.
These are of the type (Y) wye or tee (T) and the delta () or pi () networks.

3. Y - Tee

4. Delta - Pi

5. Delta to Wye Conversion
Each resistor in the Y-network is the product of the resistors in the two adjacent  branches, divided by the sum of the three  resistors.

6. Wye to Delta Conversions
Each resistor in the  network is the sum of all possible products of Y resistors taken two at a time, divided by the opposite resistor.

7. Delta-Wye Chart

8. Balanced Networks Y and  networks are said to be balanced when
and when
Under these conditions, conversion formulas become

9. Examples
Transform the delta network to its equivalent wye network.

10. Examples First, transform your network into its opposite network.
Second, calculate the new values for your network.
Third, erase the old network.

11. Examples

12. Examples

13. Examples