Calculating Energy in an RC Circuit

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SUMMARY

The discussion focuses on calculating energy in an RC circuit, specifically proving that the energy stored in the capacitor during charging equals half the energy supplied by the EMF. The other half of the energy is lost as heat in the resistor, which must be demonstrated through calculations rather than relying solely on conservation of energy. Key equations include power equations P = dW/dt, P = IV, and the charging equation q = Q(1-e^(-t/(RC)).

PREREQUISITES
  • Understanding of RC circuits and their components (resistor, capacitor, EMF)
  • Familiarity with power equations in electrical circuits
  • Knowledge of calculus for integration and differentiation
  • Ability to manipulate exponential functions in the context of charging equations
NEXT STEPS
  • Study the derivation of energy stored in a capacitor using the formula U = 1/2 CV^2
  • Learn about energy dissipation in resistors and the relationship with power loss
  • Explore the integration of power over time to find total energy in circuits
  • Investigate the implications of the time constant (τ = RC) in charging and discharging processes
USEFUL FOR

Students studying electrical engineering, physics enthusiasts, and anyone looking to deepen their understanding of energy calculations in RC circuits.

Jahosaphatz
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Homework Statement



I have an RC Circuit. There's the EMF (voltage supplier; battery), a resistor, and a capacitor. They are all in series. I need to prove that

--the energy stored in the capacitor through it charging equals 1/2 the energy supplied by the EMF

Then I need to show

--how much energy is lost by the resistor (which should be the other 1/2 of the energy supplied by the EMF by conservation of energy) and I need to prove it other than just using conservation of energy.

Since this problem is all ratios, you can use whatever variables you want (E, i, Q, V, etc) so long as they cancel

Homework Equations



P = dW/dt

P = IV = I^2R = V^2/R

q = Q(1-e^(-t/(RC)))

There may be more I need.. I really don't know..

The Attempt at a Solution



I'm thinking to use power, which is dW/dt, and integrate indefinitely. I don't know how to incorporate the charging equation, but I'm pretty sure its part of determining the energy of the capacitor?
 
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You're on the right track. Use I = dQ/dt, calculate the current through the resistor, use this to calculate the power, and integrate.
 

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