Page 935 - College Physics For AP Courses

Chapter 21 | Circuits, Bioelectricity, and DC Instruments 923
21 CIRCUITS, BIOELECTRICITY, AND DC INSTRUMENTS
Figure 21.1 Electric circuits in a computer allow large amounts of data to be quickly and accurately analyzed.. (credit: Airman 1st Class Mike Meares, United States Air Force)
Chapter Outline
21.1. Resistors in Series and Parallel
21.2. Electromotive Force: Terminal Voltage
21.3. Kirchhoff’s Rules
21.4. DC Voltmeters and Ammeters
21.5. Null Measurements
21.6. DC Circuits Containing Resistors and Capacitors
Connection for AP® Courses
Electric circuits are commonplace in our everyday lives. Some circuits are simple, such as those in flashlights while others are extremely complex, such as those used in supercomputers. This chapter takes the topic of electric circuits a step beyond simple circuits by addressing both changes that result from interactions between systems (Big Idea 4) and constraints on such changes due to laws of conservation (Big Idea 5). When the circuit is purely resistive, everything in this chapter applies to both DC and AC. However, matters become more complex when capacitance is involved. We do consider what happens when capacitors are connected to DC voltage sources, but the interaction of capacitors (and other nonresistive devices) with AC sources is left for a later chapter. In addition, a number of important DC instruments, such as meters that measure voltage and current, are covered in this chapter.
Information and examples presented in the chapter examine cause-effect relationships inherent in interactions involving electrical systems. The electrical properties of an electric circuit can change due to other systems (Enduring Understanding 4.E). More specifically, values of currents and potential differences in electric circuits depend on arrangements of individual circuit components (Essential Knowledge 4.E.5). In this chapter several series and parallel combinations of resistors are discussed and their effects on currents and potential differences are analyzed.
In electric circuits the total energy (Enduring Understanding 5.B) and the total electric charge (Enduring Understanding 5.C) are conserved. Kirchoff’s rules describe both, energy conservation (Essential Knowledge 5.B.9) and charge conservation (Essential