Can someone clarify this for me re:electric circuit

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Discussion Overview

The discussion revolves around the functioning of electric circuits, specifically focusing on the relationship between voltage, current, and resistance as described by Ohm's Law (V=IR). Participants explore the concept of voltage drop across components in a circuit, particularly in relation to a battery and a resistor, and the underlying mechanisms that drive current flow in the circuit.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses a lack of understanding of electricity and seeks clarification on how current flows back to the battery's low potential terminal after passing through a resistor.
  • Another participant notes that ideally, wires have zero resistance, leading to negligible voltage drop across them, but acknowledges that in practice, there is a small resistance.
  • A participant explains that measuring potential difference across the battery terminals shows a voltage difference that drives current through the circuit.
  • There is a discussion about the unequal affinity for electrons at the battery terminals, which is suggested as a driving force for current flow in the circuit.
  • One participant mentions that the battery eventually wears out as the terminals approach equilibrium potential, leading to a potential difference of zero.

Areas of Agreement / Disagreement

Participants generally agree on the basic principles of voltage, current, and resistance, but there are nuanced discussions about the implications of voltage drop across wires and the mechanisms driving current flow, indicating some unresolved aspects of the topic.

Contextual Notes

There are assumptions about ideal versus practical scenarios regarding wire resistance and voltage drop that remain unexamined. The discussion also touches on the chemistry of batteries, which may not be fully accurate or complete.

Seekinfo
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Hello
I have never had a good grasp of electricity/circuits but it's never late to learn so
I hope you all can help me so I can help my son.
If I connect a battery to a resistor and form a circuit, I know the "voltage drop"
current and resistance relate by V=IR. Now, my understanding is that in this circuit, the whole source voltage would be dropped across the resistor, so... what pushes the electrons (once past the resistor) back to the low zero potential terminal??

Thanks for your help, I appreciate it
 
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Ideally speaking, the wires have zero resistance. So, voltage across the wires is zero. But practically, there's some resistance(but very small compared to the resistors), hence, there is a very small voltage across the wires, which is approximated to 0.
 
Thank you sir. That makes sense to me. Thank you
 
Seekinfo said:
Thank you sir.
You are welcome! But I'm not a 'sir'. I'm of your son's age(maybe a couple of years older..):smile:.
 
great. I'm glad you helped us out
 
cnh1995 said:
You are welcome! But I'm not a 'sir'. I'm of your son's age(maybe a couple of years older..):smile:.
You are clearly worthy of the title 'sir'. Don't denigrate yourself.:smile:
Agewise, I am a 'sir' for most of the people I meet but many of them still call me a dozy old twozzer.
 
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sophiecentaur said:
You are clearly worthy of the title 'sir'. Don't denigrate yourself.:smile:
Agewise, I am a 'sir' for most of the people I meet but many of them still call me a dozy old twozzer.
Thank you! That is very kind of you:smile:!
 
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cnh1995 points out the there is little voltage drop across the wires (ideally). This is true. Suppose you take a voltmeter and measure the potential difference from a point right after the battery, to the negative terminal (usually the flat surface without the nub in the battery). The voltmeter measures zero potential difference, so it is natural to ask, "what drives the current back to the negative terminal?".(You call it the zero potential terminal).

But if you take the voltmeter and measure the potential difference from a point right after the positive terminal, and a point right before the resistor, you will also get a potential difference of zero. You could just as easily ask, "what drives the current towards the resistor in the first place?"
The answer is that a voltage difference drives the current. A voltmeter measuring the potential difference across the terminals of the battery might be for instance 1.5 V. As cnh correctly points out the wires are good conductors so they offer almost no voltage drop. The voltage drop across the resistor is approximately the voltage drop across the battery terminals. This potential difference drives current through the resistor.

The chemistry of the battery demonstrates two terminals with unequal affinity for electrons. (My apology to the chemists, the rest may be half-truths, it has been over 40 years since I took chemistry.) The positive terminal may be +1.5 V with respect to the negative terminal at 0 V. This means electrons will want to flow to the positive terminal. (Unlike charges attract). Ultimately, it is this unequal affinity that drives the current in the circuit. Eventually the battery does wear out, and the two terminals approach an equilibrium potential with 0 potential difference, and the battery is disposed of, or recharged or whatever
 
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