1. Back to the Bridge Which resistors are in series?
Which resistors are in parallel?
ECE 201 Circuit Theory I

2. Delta (Δ) Connection
Resistors R1, R2, and Rm (or R3, Rm, and Rx) are in a Delta (Δ), or pi (π) connection.
ECE 201 Circuit Theory I

3. Wye (Y) Connection
Resistors R1, Rm, and R3 (or R2, Rm, and Rx) are in a wye (Y), or tee (T) connection.
ECE 201 Circuit Theory I

4. Δ – Y Conversion
ECE 201 Circuit Theory I

5. Δ – Y Conversion (continued)
The resistance between the terminal pairs must be the same for both circuits
ECE 201 Circuit Theory I

6. Δ – Y Conversion (continued)
After some algebraic manipulation
ECE 201 Circuit Theory I

7. Y – Δ Conversion
ECE 201 Circuit Theory I

8. Y – Δ Conversion (continued)
The resistance between the terminal pairs must be the same for both circuits
ECE 201 Circuit Theory I

9. Y – Δ Conversion (continued)
After some algebraic manipulation
ECE 201 Circuit Theory I