1. 20.3 Complex Resistor Combinations Date, Section, Pages, etc. Mr. Richter

2. Agenda  Warm-Up  Review HW  p. 744 #1-4  p. 745 #1-6  Complex Resistor Combinations  Complex Circuit Problem Solving  Equivalent Resistance  Current and Voltage Drops

3. Objectives: We Will Be Able To…  Determine the equivalent resistance of a complex resistor combination.  Determine the current through and voltage drop across a resistor within a complex resistor combination.

4. Warm-up  Calculate the equivalent resistance of an 8.0 Ω resistor and a 4.0 Ω resistor arranged in parallel.

5. Complex Resistor Combinations

6.  Most circuits are not purely series circuits or purely parallel circuits.  Most circuits are a combination of series and parallel circuits.

7. Equivalent Resistance

8.  To determine the equivalent resistance in a complex circuits: 1.Redraw the circuit in a line. 2.Combine all resistors in series and redraw 3.Combine all resistors in parallel and redraw 4.Repeat

9. Equivalent Resistance: Redraw the Circuit in a Line =

10. Equivalent Resistance: Resistors in Series 3.0 Ω 6.0 Ω 2.0 Ω 4.0 Ω 1.0 Ω

11. Equivalent Resistance: Resistors in Series 3.0 Ω 6.0 Ω 2.0 Ω 4.0 Ω 1.0 Ω 8.0 Ω 9.0 Ω

12. Equivalent Resistance: Resistors in Parallel 4.0 Ω 1.0 Ω 8.0 Ω 9.0 Ω

13. Equivalent Resistance: Resistors in Parallel 1.0 Ω 4.0 Ω 8.0 Ω 9.0 Ω 2.7 Ω

14. Equivalent Resistance: Repeat (Resistors in Series) 1.0 Ω 9.0 Ω 2.7 Ω 12.7 Ω

15. Current and Voltage Drops

16.  To find the current through and voltage drop across a specific resistor, work your way back from the equivalent resistors! 1.Calculate the current. 2.Then the voltage drops. 3.Redraw and repeat. 12.7 Ω = 3.0 Ω 6.0 Ω 2.0 Ω 4.0 Ω 1.0 Ω

17. Current and Voltage Drops 12.7 Ω I = 0.71 A 1.0 Ω 9.0 Ω 2.7 Ω

18. Current and Voltage Drops I = 0.71 A 1.0 Ω 9.0 Ω 2.7 Ω V = 1.9V

19. Current and Voltage Drops 1.0 Ω 4.0 Ω 8.0 Ω 9.0 Ω 2.7 Ω V = 1.9V

20. Current and Voltage Drops 1.0 Ω 4.0 Ω 8.0 Ω 9.0 Ω V = 1.9VI = 0.24 A 6.0 Ω 2.0 Ω

21. Current and Voltage Drops 1.0 Ω 4.0 Ω 9.0 Ω I = 0.24 A 6.0 Ω 2.0 Ω V = (0.24 A)(2.0 Ω ) V = 0. 48 V

22. Wrap-Up: Did we meet our objectives?  Determine the equivalent resistance of a complex resistor combination.  Determine the current through and voltage drop across a resistor within a complex resistor combination.

23. Homework  Due Thursday:  p. 752 #1-9