Capacitors in Series and Parallel

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Capacitors in Series and Parallel

• 20.12

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Capacitors

• A device that stores electric charge
• Two parallel plates separated by some distance
• q CV
• E ½ CV2
• Unit Farads (F)
• Circuit diagram

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Parallel Capacitors

• Add the charges of the capacitors
• q q1 q2 C1V C2V CPV
• CP C1 C2

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Series Capacitors

• All capacitors in series store the same charge
  regardless of their capacitances
• The charge stored in the first charges the second
  by induction
• V V1 V2 q/C1 q/C2 q/CS

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Example

• An electric circuit was accidentally constructed
  using a 5.0 ?F capacitor instead of the required
  16 ?F value. What can a technician do to correct
  this circuit?
• Add a 11 ?F capacitor in parallel with the first
  one.

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Example 2

• You have three capacitors. How can you arrange
  them to give the greatest capacitance?
• Parallel
• Least capacitance?
• Series

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Example 3

• Determine the equivalent capacitance of the
  circuit shown if C1 C2 2C3 12.5 ?F.
• How much charge is stored on each capacitor when
  V 45.0 V?

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Practice Problems

• Test your capacitance for these types of problems
• 616 P86 89
• Total of 4 Problems