Electrostatics in RC\DC Circuits-feedback process

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SUMMARY

The discussion centers on the feedback process in RC and DC circuits, emphasizing the electrostatic behavior of surface charges on wires. Participants highlight the importance of understanding how these surface charges create a steady electric field that facilitates the movement of free electrons. A key point raised is the necessity for current to equalize within a wire, as any discrepancy between incoming (I1) and outgoing (I2) currents leads to an unstable state, potentially causing infinite charge accumulation. The conversation references Chabay's textbook for foundational concepts but calls for deeper exploration of the feedback mechanism and its mathematical underpinnings.

PREREQUISITES
  • Understanding of basic circuit theory, including Ohm's Law.
  • Familiarity with electrostatics and electric fields.
  • Knowledge of RC circuit behavior and time constants.
  • Concepts of charge accumulation and current flow in conductive materials.
NEXT STEPS
  • Research the mathematical modeling of feedback processes in electrical circuits.
  • Study the role of surface charges in electrostatics, particularly in conductive materials.
  • Explore Chabay's textbook for detailed explanations of current equalization in circuits.
  • Examine the implications of charge accumulation on circuit stability and performance.
USEFUL FOR

Electrical engineers, physics students, and educators seeking a deeper understanding of circuit dynamics, particularly the electrostatic principles influencing current flow and stability in RC and DC circuits.

Dweirdo
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Hello,

I've always had problems conceptualizing the physics behind circuits, and it always felt like information is hidden from me.

Lately I've been trying to analyze circuits in the microscopic and electrostatic way, as i think it is crucial for real understanding of circuit concepts.

I've found many articles suggesting about the surface charges piled on the surface of the wires that finally make the nearly steady and parallel to the wire electric field that moves the free electrons inside the wire(knowledge that wasn't given in any introductory physics course i know of).

Anyway, there is one concept which is mentioned in all these articles and chabay's textbook but isn't covered to it's fullest(IMO), the feedback process.
That fast process where the electrons move and pile periodically so that the circuit will finally be in a steady-state, where the current is constant.
I'm interested in the way it happens, both the mathematical and conceptual ideas behind this process, why is the current must be constant through a wire with constant resistance.

Why a state where current I1 is entering a section of a wire and a current I2 leaves this section where I2 < I1, is not a stable state , and it will tend to equalize these two Currents?

Thank you in advance.
 
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Dweirdo said:
Why a state where current I1 is entering a section of a wire and a current I2 leaves this section where I2 < I1, is not a stable state , and it will tend to equalize these two Currents?

If I2 < I1 then the charge of that section of wire is increasing. Unless I2 eventually approaches I1, the charge in the section of wire and the potential energy would grow towards infinity!
 
That seems reasonable, I'm interested in they way these currents are equalized, the access charge in that section sticks to the surface of the wire(how does it get there??) and dampens I1 and Increases I2?
 

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