Fundamentals of Physics 8/e 27 - Circuit Theory

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1 Fundamentals of Physics 8/e 27 - Circuit Theory
D. Halliday, R. Resnick, and J. Walker 國立彰化師大教學卓越計畫 理學院普通物理整合型教材 主持人：郭艷光院長

2 彰化師大教學卓越－普物教材－理學院長郭艷光主持
Outline 27-1 What Is Physics? 27-2 “Pumping” Charges 27-3 Work, Energy, and Emf 27-4 Calculating the Current in a Single-Loop Circuit 27-5 Other Single-Loop Circuits 27-6 Potential Difference Between Two Points 27-7 Multiloop Circuits 27-8 The Ammeter and the Voltmeter 27-9 RC Circuits 彰化師大教學卓越－普物教材－理學院長郭艷光主持

3 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-1 What Is Physics? In this chapter we cover the physics of electric circuits that are combinations of resistors and batteries and capacitors. We restrict our discussion to circuits through which charge flows in one direction, which are called either direct-current circuits or DC circuits. 彰化師大教學卓越－普物教材－理學院長郭艷光主持

4 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-2 “Pumping” Charges In order to create a current through a resistor, a potential difference must be created across its terminals. One way of doing this is to connect the resistor to a battery. A device that can maintain a potential difference between two terminals is called a “seat of an emf” or an “emf device”. 彰化師大教學卓越－普物教材－理學院長郭艷光主持

5 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-3 Work, Energy, and Emf pump High (+) reservoir Low (-) reservoir V i Ideal emf device V i Real emf device 彰化師大教學卓越－普物教材－理學院長郭艷光主持

6 27-4 Calculating the Current in a Single-Loop Circuit
彰化師大教學卓越－普物教材－理學院長郭艷光主持

7 27-4 Calculating the Current in a Single-Loop Circuit
Resistance Rule: For a move through a resistance in the direction of the current, the change in the potential For a move through a resistance in the direction opposite to that of the current, the change in the potential R i motion R i motion EMF Rule: For a move through an ideal emf device in the direction of the emf arrow, the change in the potential For a move through an ideal emf device in a direction opposite to that of the emf arrow, the change in the potential motion + - motion + - 彰化師大教學卓越－普物教材－理學院長郭艷光主持

8 27-5 Other Single-Loop Circuits
彰化師大教學卓越－普物教材－理學院長郭艷光主持

9 27-5 Other Single-Loop Circuits
Resistances in series : When a potential difference V is applied across resistances connected in series, the resistances have identical currents i. The sum of the potential differences across the resistances is equal to the applied potential difference V. 彰化師大教學卓越－普物教材－理學院長郭艷光主持

10 27-6 Potential Difference Between Two Points
Vf －Vi =ΔV Left path: Vb－Va=E－ir Right path: Vb－Va=iR Note: The values if Vb－Va we get from the two paths are the same. 彰化師大教學卓越－普物教材－理學院長郭艷光主持

11 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-7 Multiloop Circuits i₁+i₃=i₂ 彰化師大教學卓越－普物教材－理學院長郭艷光主持

12 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-7 Multiloop Circuits Resistances in Parallel: When a potential difference V is applied across resistances connected in parallel, the resistances all have that same potential difference V. 彰化師大教學卓越－普物教材－理學院長郭艷光主持

13 27-8 The Ammeter and the Voltmeter
彰化師大教學卓越－普物教材－理學院長郭艷光主持

14 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-9 RC Circuits + - i Charging of a capacitor 彰化師大教學卓越－普物教材－理學院長郭艷光主持

15 彰化師大教學卓越－普物教材－理學院長郭艷光主持
27-9 RC Circuits + - i Discharging of a capacitor q t qo O 彰化師大教學卓越－普物教材－理學院長郭艷光主持

16 彰化師大教學卓越－普物教材－理學院長郭艷光主持
End of chapter 27! 彰化師大教學卓越－普物教材－理學院長郭艷光主持