Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley PowerPoint Lectures for College Physics, Eighth Edition Hugh D. Young and Robert M. Geller Lectures by James L. Pazun Chapter 22 Alternating Current

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Goals for Chapter 22 To study phasors and alternating current. To explore and calculate resistance and reactance. To diagram and solve examples of the series R-L-C circuit. To calculate and graph power in alternating – current circuits. To study series and parallel resonance.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Alternating current - Figure 22.1 A coil of wire rotating with constant angular velocity in a magnetic field develops a sinusoidal oscillating current. The potential will vary from a maximum V at a frequency ω (or, by a factor of 2π, as f in Hz).

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley What are phasors? – Figure 22.2 Phasors are graphic representations of location. In two dimensions, you can locate a unique point with a radius vector of length L and its angle with respect to zero. This figure refers to conceptual analysis 22.1.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Root-Mean-Square averages – Figure 22.4 Refer to example 22.4 in your text.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Resistance and Reactance – Figure 22.6 For a circuit such as one shown at the right, there is a resistor and one can calculate the potential and current. BUT in an AC circuit, these are functions of time.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley An Inductor in a circuit – Figure 22.7 Refer to Example 22.2 in your text. The circuit leads to the RMS graph which leads to the phasor diagram.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley A capacitor in an AC circuit – Figure 22.8 Even though we don’t think of capacitors as transparent to current, we can have one plate charge then immediately have the opposing plate charge. We think of AC as going past or through a capacitor.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Capacitors and AC circuits II – Figures 22.9,10 Refer to the worked examples in Conceptual Analysis 22.2 and also in Example For use with the conceptual analysis. For use with the worked example on page 743.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley The series R-L-C circuit – Figure Consumer electronics would be a good place to find such a circuit.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Current and voltage may be found – Figure As in Figure 22.8, here too we can follow the logic from circuit to phasor diagrams.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley R-L-C Circuits – Figure Refer to worked Example 22.4 and Conceptual Analysis You will want to take advantage of the Problem Solving Strategy 22.1

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Power in Alternating Current Circuits – Figure AC current behaves differently with respect to power than DC current. It was the crucial difference that made long-distance wiring possible.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Power in AC Circuits II – Figures 22.16,17 Follow from phasor diagram to Conceptual Analysis 22.4 to worked Examples 22.5 and “Generic” diagram Specific to the Conceptual Analysis

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Series Resonance – Figure Since the AC flow is expressed in terms of frequency, it follows that just like in music, these frequencies can resonate.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Series resonance II – Figures 22.19, 20 Refer to Conceptual Analysis 22.5 and worked Example A “generic” diagram illustrating waveforms in resonance.

Copyright © 2007 Pearson Education, Inc. publishing as Addison-Wesley Parallel resonance – Figure Refer to worked Example 21.8 in your text.