1. ECE 201 Circuit Theory I1 Assessment Problem #4.7 Page 102 of the text by Nilsson and Riedel

2. ECE 201 Circuit Theory I2 Determine the power delivered by the 80 V source and the power dissipated in the 8 Ω resistor using the mesh-current method.

3. ECE 201 Circuit Theory I3 I1I1 I2I2 I3I3 Identify the mesh currents

4. ECE 201 Circuit Theory I4 I1I1 I2I2 I3I3 +-+- + -+ - + - +--+ +- Assign the voltage polarities

5. ECE 201 Circuit Theory I5 I1I1 I2I2 I3I3 +-+- + -+ - + - +--+ +- 80 = 31I 1 - 26I 2 - 5I 3 Write the mesh-current equations (1)

6. ECE 201 Circuit Theory I6 I1I1 I2I2 I3I3 +-+- + -+ - + - +--+ +- 80 = 31I 1 - 26I 2 - 5I 3 0 = -26I 1 +124I 2 -90I 3 Write the mesh-current equations (2)

7. ECE 201 Circuit Theory I7 I1I1 I2I2 I3I3 +-+- + -+ - + - +--+ +- 80 = 31I 1 - 26I 2 - 5I 3 0 = -26I 1 +124I 2 -90I 3 0 = -5I 1 -90I 2 +125I 3 Write the mesh-current equations (3)

8. ECE 201 Circuit Theory I8 Write the equations in matrix form

9. ECE 201 Circuit Theory I9 Check for off-diagonal symmetry

10. ECE 201 Circuit Theory I10 Solving with TI-89 Check CATALOG for simult( --- press ENTER [31,-26,-5;-26,124,-90;-5,-90,125],[80;0;0]) hit ENTER Resulting column vector is I 1 = 5A I 2 = 2.5A I 3 = 2A

11. ECE 201 Circuit Theory I11 Calculate the power delivered by the source P source = (V source )(I 1 ) = (80V)(5A) = 400 W I 1 = 5 A + -

12. ECE 201 Circuit Theory I12 Calculate the power dissipated in the 8Ω resistor P 8Ω = (I 2 ) 2 R = (2.5) 2 (8) = 50 W I 2 = 2.5 A