Confused about Current Flow & Capacitances

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Discussion Overview

The discussion revolves around the concepts of current flow and capacitance, particularly in the context of electrochemical cells and the implications of charge movement in electrical circuits. Participants explore the relationship between potential energy and charge movement, as well as the historical conventions surrounding charge designation.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion regarding the description of charge movement from low potential to high potential, contrasting it with the analogy of water flowing from high to low elevation.
  • Another participant suggests that the confusion arises from the sign convention used for charge, noting that electrons, which have a negative charge, move in the opposite direction to the conventional current flow.
  • A third participant indicates understanding after clarification, stating that electrons lose potential energy as they move from low potential to high potential.
  • Another participant elaborates on the operation of a chemical battery, explaining that chemical reactions create a potential difference and that current flows from the positive to the negative terminal according to conventional current flow, despite the actual movement of electrons being in the opposite direction.

Areas of Agreement / Disagreement

Participants exhibit some agreement on the role of chemical reactions in establishing potential differences in batteries, but there remains confusion and differing interpretations regarding the implications of charge movement and the sign convention used in electrical theory.

Contextual Notes

There are unresolved questions regarding the implications of the sign convention on understanding current flow and potential energy, as well as the historical context of charge designation that may affect clarity in discussions of electrical circuits.

D_DaYwAlKeR
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I have some doubts regarding Current Flow and Capacitances...

I Read this somewhere..
" an electrochemical cell supplies energy to move a charge from its low energy, low potential terminal to the high energy, high potential terminal. In this sense, the cell supplies the energy to establish an electric potential difference across the two ends of the external circuit. Charge will then flow through the external circuit in the same manner that water will flow from an elevated position to a low position. It is the difference in potential that causes this flow..."


it says that charge (electron) will travel from Low potential to high potential...
then its says that it will move in the same manner that water will flow from an elevated position to a low position..( high potential to low potential...) ..i didnt get this at all..!
 
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D_DaYwAlKeR said:
it says that charge (electron) will travel from Low potential to high potential...
then its says that it will move in the same manner that water will flow from an elevated position to a low position..( high potential to low potential...) ..i didnt get this at all..!

It's just a matter of a sign convention, because electrons are said to have negative charge. Life would be a lot easier if a century and a half ago we had decided to call the electron's charge "positive" instead of "negative" so that they would naturally move from areas of high "positive" charge to low "positive" charge - but back then we didn't know which direction the physical charge carriers were moving, and arbitrarily chose a sign convention that turns out to be inconvenient for talking about electrons.

To this day we take power from the positive terminal of a battery, and talk about the wiring diagram as if electrical current is flowing "downhill" from the positive terminal; but what's actually happening physically is that electrons are flowing "uphill" from the negative terminal.
 
I got it nw...

Electron loses potential energy as it moves from low potential to high potenital..!...thnxx...@Nugatory!
 
I believe the beginning they are talking about a chemical battery; it talks about moving the charge from a low energy state to a high energy state.

In a battery, a chemical reaction supplies the energy to separate the charges between the cathode and anode, which causes an electrical potential difference across the terminals and puts the charges into a high potential energy state. When the terminals are connected by a conductor, the stored energy is releases as current. And as Nugatory said, the convention is to label the current as flowing from positive to negative.
 

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