1. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley PowerPoint ® Lectures for University Physics, Twelfth Edition – Hugh D. Young and Roger A. Freedman Lectures by James Pazun Chapter 31 Alternating Current

2. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Goals for Chapter 31 To introduce phasors and alternating current To study voltage, current, and phase angle To consider resistance and reactance To introduce impedance and its application to the L-R-C series circuit To consider power in AC circuits To see resistance in AC circuits To apply AC knowledge to transformers

3. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Introduction After Thomas Edison found a filament that worked for his new invention, the light bulb, he tried to design a system to send power from one place to another across large distances. He quickly found that I2R power loss in the cables was frustrating, essentially a collection of resistance heaters. Another fortuitous application of AC current in long metal conductors was the creation of electromagnetic waves.

4. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley AC current Notice the new electronic symbol at the top of page 1062. Consider phasor diagrams. Review Figure 31.1. Explain Figure 31.2. (Until now, only Captain Kirk came to mind when someone said “phasor.”)

5. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley A full-wave rectifier circuit Refer to Figure 31.3 at right and 31.4 below.

6. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Current in the device I’m using right now A desktop PC draws current from a plug to the wall, but what are the details? Smile at Figure 31.5. (It’s what we’re doing.) Follow Example 31.1, illustrated by Figure 31.6.

7. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Resistors in an AC circuit Ohm’s Law applied in oscillatory fashion. Consider Figure 31.7.

8. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Inductors in an AC circuit Replace the resistor in the previous slide with an inductor. Consider Figure 31.8. Follow Example 31.2.

9. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Capacitance in an AC circuit Because this is a series circuit, the current is the same through the capacitor as through the resistor just considered. Consider Figure 31.9 at right. Follow Example 31.3. Figure 31.10 (below) illustrates Example 31.3.

10. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Comparing AC circuit elements Table 31.1 (bottom) provides a valuable summary/comparison for circuit elements. Figure 31.11 (below) shows items as a function of the angular frequency.

11. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley The loudspeaker, a useful application The woofer (low tones) and the tweeter (high tones) connect in parallel through a “crossover.” Consider Figure 31.12.

12. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley The L-R-C circuit Refer to Figure 31.13 at the bottom of the page. Read Problem-Solving Strategy 31.1. Follow Example 31.4. Figure 31.14 (at right) shows a fun example!

13. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley An L-R-C circuit II Follow Example 31.5 below.

14. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Power in an inductor Consider current, voltage, and power as functions of time. Consider Figure 31.16 below. Follow Examples 31.6 and 31.7.

15. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Circuit behavior at resonance Look at the maximum I when the impedance is a minimum. Refer to Figure 31.18.

16. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Tuning a radio Follow Example 31.8. Figure 31.20 illustrates the example.

17. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Transformers We drive by them, carry them, and sit in front of them. Notice the new circuit symbol at the bottom of page 1080. Consider Figure 31.21 below and Figures 31.22 and 31.23 at right.

18. Copyright © 2008 Pearson Education Inc., publishing as Pearson Addison-Wesley Transformers II Consider Figure 31.24. Follow Example 31.9.