15. DC Circuits with Capacitors

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Learning Objectives

  • To be able to include capacitors as one of our circuit elements, and to know how the electric potential changes across capacitors.
  • To be able to calculate the currents in multi-loop circuits including capacitors using Kirchoff's Laws.
  • To comprehend the nature of the differential equation describing a charging and discharging capacitor, and to be able to write down solutions to those equations.
  • To be able to explain the meaning of the RC time constant, and how you would measure it.
  • To be able to explain the power balance in a circuit where a capacitor is charging and in a circuit where it is discharging.

Preparation

Course Notes

Read through the course notes before watching the video.  The course note files may also contain links to associated animations or interactive simulations. 

Read sections 7.6 through 7.11:
Direct-Current Circuits (PDF)

Lecture Video

Video Excerpts

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Download the complete lectures from this course:

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Learning Activities

Guided Activities

Read through the class slides. They explain all of the concepts from the module.

Slides (PDF)

Self-Assessment

Do the Concept Questions first to make sure you understand the main concepts from this module. Then, when you are ready, try the Challenge Problems.

Concept Questions

Concept Questions (PDF)

Solutions (PDF)

Challenge Problems

Challenge Problems (PDF)

Solutions (PDF)

Problem Solving Help

Watch the Problem Solving Help video for insights on how to approach and solve problems related to the concepts in this module.

Problem: Discharging a Capacitor

A capacitor is charged to a potential of 15 V and is then connected to a voltmeter having an internal resistance of 2.25 MΩ. After a time of 5 s, the voltmeter reads 5 volts. What is the capacitance?

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» Internet Archive (MP4 - 8MB)

 

 

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