Capacitor current in function of time

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SUMMARY

The discussion focuses on calculating the current (i) in a circuit consisting of a generator (U), a resistor (R), and a capacitor (C) as a function of time. The user seeks to understand the relationship between voltage (V), charge (Q), and current (I) during the capacitor's charging process. Key equations mentioned include V = Q/C and V = U - R.i, along with the integral form of current, I = ∫(C.dV/dt). The conversation emphasizes the need to integrate these concepts to derive the current and energy dissipated by the resistor.

PREREQUISITES
  • Understanding of basic electrical circuit components: generator, resistor, and capacitor.
  • Familiarity with Ohm's Law and Kirchhoff's voltage law.
  • Knowledge of calculus, specifically integration techniques.
  • Concept of charge (Q) and its relationship with current (I) and voltage (V).
NEXT STEPS
  • Study the derivation of the capacitor charging equation in RC circuits.
  • Learn about the time constant (τ = RC) and its effect on current and voltage over time.
  • Explore energy dissipation in resistors using the formula P = I²R.
  • Investigate the Laplace transform as a method for solving differential equations in circuits.
USEFUL FOR

Electrical engineering students, circuit designers, and anyone interested in analyzing transient responses in RC circuits.

jaumzaum
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In a circuit of 1 generator (U) 1 resistor (R) and one capacitor (C), how do I calculate the current i in function of time,
as well as the energy dissipated by the resistor during the time the capacitor is charged?
 
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Sorry, you will need to show us some effort before you get any help.
 
I have no idea on how to solve this.


I would try to integrate I

[itex]\int \frac{C.dV}{dt}[/itex]

But V changes during time

I think [itex]V = Q/C[/itex]
[itex]V=U-R.i[/itex] and
[itex]Q = \int I.dt[/itex]

But how do I put all together?
 
Last edited:

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