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Outline
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Alexander-Sadiku
Fundamentals of Electric Circuits
  • Chapter 11
  • AC Power Analysis
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AC Power Analysis
Chapter 11

  • 11.1 Instantaneous and Average Power
  • 11.2 Maximum Average Power Transfer
  • 11.3 Effective or RMS Value
  • 11.4 Apparent Power and Power Factor
  • 11.5 Complex Power
  • 11.6 Conservation of AC Power
  • 11.7 Power Factor Correction
  • 11.8 Power Measurement
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11.1 Instantaneous and Average Power (1)
  • The instantaneously power, p(t)
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11.1 Instantaneous and Average Power (2)
  • The average power, P, is the average of the instantaneous power over one period.
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11.1 Instantaneous and Average Power (3)
  • Example 1


  • Calculate the instantaneous power and average power absorbed by a passive linear network if:
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11.1 Instantaneous and Average Power (4)
  • Example 2


  • A current                flows through an impedance                       . Find the average power delivered to the impedance.
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11.2 Maximum Average Power Transfer (1)
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11.2 Maximum Average Power Transfer (2)
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11.3 Effective or RMS Value (1)
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11.3 Effective or RMS Value (2)
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11.4 Apparent Power and Power Factor (1)
  • Apparent Power, S, is the product of the r.m.s. values of voltage and current.
  • It is measured in volt-amperes or VA to distinguish it from the average or real power which is measured in watts.







  • Power factor is the cosine of the phase difference between the voltage and current. It is also the cosine of the angle of the load impedance.
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11.4 Apparent Power and Power Factor (2)
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11.5 Complex Power (1)
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11.5 Complex Power (2)
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11.5 Complex Power (3)
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11.5 Complex Power (4)
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11.6 Conservation of AC Power (1)
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11.7 Power Factor Correction (1)
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11.7 Power Factor Correction (2)
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11.8 Power Measurement (1)