Steady state of inductors and capacitors

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Discussion Overview

The discussion revolves around the concept of steady state in inductors and capacitors, particularly in the context of DC circuits. Participants explore the definitions, implications, and conditions of steady state, including energy consumption and storage in these components.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant seeks clarification on the meaning of steady state, questioning whether it implies constant current flow and expressing confusion over conflicting statements in their textbook regarding current and voltage in steady state.
  • Another participant confirms that energy consumed is zero in steady state DC for both inductors and capacitors, noting that this is due to the voltage across the inductor being zero and the capacitor having no current.
  • A participant reiterates their confusion about why energy is zero in steady state DC and asks for a clearer definition of steady state.
  • Another participant questions whether it is necessary for the energy stored in a capacitor to be zero in steady state, referencing a scenario where the energy stored has a certain value.
  • One participant provides a simple definition of steady state, stating that it means voltages and currents are not changing, and explains that energy dissipation is zero for inductors due to zero voltage and for capacitors due to zero current.
  • A participant raises a question about the necessity of both current and voltage being constant in steady state, suggesting a scenario where one could be constant while the other changes.
  • A later reply emphasizes that steady state is reached when all currents and voltages are unchanging with time, specifically in the context of DC circuits.

Areas of Agreement / Disagreement

Participants express differing views on the implications of steady state, particularly regarding energy storage and dissipation in inductors and capacitors. There is no consensus on whether energy stored in a capacitor must be zero in steady state, and the definition of steady state itself is debated.

Contextual Notes

Some participants reference specific conditions and definitions that may not be universally accepted or clearly defined, leading to potential misunderstandings regarding the nature of steady state in electrical circuits.

ranju
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First of all..I want to be clear about steady state..what actually it means..?? Does it mean state of constant current flowing across..?
In my book..its written that in steady state current in inductor and voltage in capacitor is zero , hence energy consumed is zero fotr both in steady state..!
How come this happens... we know that in steady state of iinductor..voltage across it is zero & that in capacitor at constant voltage across it..cureent through it is zero...!
Are'nt the two statements contrasting each other..??
pleasez explain clearly...:frown:
 
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energy consumed is zero in steady state DC for both. However, as you pointed out it is indeed because voltage across inductor = 0, and capacitor has no current. Are you sure the book says the opposite?

Here is a link for a clearer explanation
http://www.usna.edu/Users/cs/vincent/suppnotes/EE301Topic14.pdf
 
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yeah,,,its exactly what I stated..
well why the energy is zero in steady state dc in both? and what about the definition of steady state?
 
and is it compulsory that in steady state the energy stored by a capacitor is zero...? Because I'hv gone through a question in which the energy stored by the capapcitor in steady state has a certain value..!
 
as a simple definition of steady state it just means that voltages and currents aren't changing. energy dissipated is zero for the inductor because there is no voltage across it. Recall P = iV. For the capacitor, there is no energy being dissipated because there is no current.

However, this should not be confused with the energy stored in the magnetic field of the inductor, or the energy stored in the electric field of the capacitor. Those are energies stored by creating the fields, 'building up' after the DC is switched on, but before the circuit reaches steady state.
 
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well..is it necesaary that in steady stete both are constant(current n coltage)..even if one is sonstant and other is changing ..will the system be in steady state then?
 
ranju said:
well..is it necesaary that in steady stete both are constant(current n coltage)..even if one is sonstant and other is changing ..will the system be in steady state then?
You are talking about DC circuits? The steady-state will be reached when all currents and voltages are unchanging with time.
 

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