How Does Power Balance in a Driven RLC Circuit?

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SUMMARY

In a driven RLC circuit, the power delivered by the source is equal to the power dissipated as heat in the resistor. The average power can be calculated using the formula Pavg = Irms * Vrms * cos(φ). While energy is exchanged between the capacitor and inductor, it does not create additional energy; instead, losses occur due to resistance, necessitating that the source replenishes this energy to maintain steady-state operation.

PREREQUISITES
  • Understanding of RLC circuit components (resistor, inductor, capacitor)
  • Familiarity with AC circuit analysis
  • Knowledge of power calculations in electrical circuits
  • Proficiency in using the formula Pavg = Irms * Vrms * cos(φ)
NEXT STEPS
  • Study the behavior of energy storage in capacitors and inductors in AC circuits
  • Learn about power factor and its impact on circuit efficiency
  • Explore the concept of reactive power in RLC circuits
  • Investigate methods to minimize energy losses in resistive components
USEFUL FOR

Electrical engineers, physics students, and anyone involved in the analysis and design of AC circuits will benefit from this discussion.

thelonious
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Homework Statement



For a driven RLC circuit, compare the power delivered by the source to the power dissipated as heat in the resistor.

Homework Equations



P[itex]_{avg}[/itex] = I[itex]_{rms}[/itex]*V[itex]_{rms}[/itex]*cos([itex]\phi[/itex])

The Attempt at a Solution



My thinking was that the power dissipated in the resistor would be less than the power delivered by the source.

I thought so because in addition to the energy radiated as heat at the resistor, energy is either being stored or being released back into the circuit by the capacitor and inductor.

However, I was told that the power at the source equals the power dissipated as heat in the resistor. If all of the source energy is accounted for by the capacitor, what happened to the energy in the inductor and capacitor?
 
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thelonious said:

Homework Statement



For a driven RLC circuit, compare the power delivered by the source to the power dissipated as heat in the resistor.

Homework Equations



P[itex]_{avg}[/itex] = I[itex]_{rms}[/itex]*V[itex]_{rms}[/itex]*cos([itex]\phi[/itex])

The Attempt at a Solution



My thinking was that the power dissipated in the resistor would be less than the power delivered by the source.

I thought so because in addition to the energy radiated as heat at the resistor, energy is either being stored or being released back into the circuit by the capacitor and inductor.

However, I was told that the power at the source equals the power dissipated as heat in the resistor. If all of the source energy is accounted for by the capacitor, what happened to the energy in the inductor and capacitor?

The inductor and capacitor are going to trade stored energy back and forth, true, but that energy is not manufactured by those components. Further, there are losses on every cycle in the resistance. The source has to replenish this energy if the circuit is to operate at a steady state.
 

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