Electric potential and earth/ground

Click For Summary

Discussion Overview

The discussion revolves around the concepts of electric potential, circuit design, and the role of grounding in electrical circuits. Participants explore whether a circuit can be created between two separate batteries without direct contact and seek clarification on how grounding functions within such circuits.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question the possibility of connecting a circuit from one terminal of a battery through a load to the opposite terminal of another battery without them touching, suggesting it may not be feasible.
  • One participant argues that a continuous flow of charge is necessary for a potential difference in a battery, indicating that without a closed loop, current cannot flow.
  • Another participant proposes that if there is a medium allowing electron transfer between the batteries, it could be possible, likening it to physically touching the batteries.
  • Grounding is discussed as a means for electrons to flow to and from the Earth, which is described as a large conductor or reserve of electrons, allowing circuits to function even when not directly connected back to the power source.
  • Some participants express confusion about how grounding allows for current flow without completing a traditional circuit loop, seeking further clarification on this concept.
  • One participant notes that in circuit theory, a ground is often idealized as an infinite source or sink for charge, which can absorb current without changing potential.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of connecting circuits between separate batteries without direct contact, with some asserting it is impossible while others suggest it could be possible under certain conditions. There is also uncertainty regarding the mechanics of grounding and its implications for circuit design.

Contextual Notes

Participants reference various examples and analogies to clarify their points, but there are unresolved questions about the specifics of electron flow and the role of grounding in circuit functionality.

Who May Find This Useful

Individuals interested in electrical engineering, circuit design, and the principles of grounding in electrical systems may find this discussion relevant.

fletch-j
Messages
19
Reaction score
0
I was just wondering if the following is true/possible:

- Could a circuit be made that is connected from a terminal on one battery, through a load, and then connected to the opposite terminal of another battery, where the batteries aren't touching?
I believe it isn't possible, but would someone be able to give a quick explanation as to why this doesn't work?

Also:
- What role does an 'earthing' or 'grounding' have in a circuit where there is an power source and then a return path to the source as well as a grounding?

- On that note, could someone please clear up exactly how circuits with a grounding in them work in general?
Circuits like this seem to defy the notion that "a circuit must be closed for current to flow"


Thanks!
 
Physics news on Phys.org
This is an example of a circuit that I'm talking about 'denying the notion that "a circuit must be closed for current to flow"'
upload.wikimedia.org/wikipedia/commons/d/db/Resistive_divider.png
 
fletch-j said:
I was just wondering if the following is true/possible:

- Could a circuit be made that is connected from a terminal on one battery, through a load, and then connected to the opposite terminal of another battery, where the batteries aren't touching?
I believe it isn't possible, but would someone be able to give a quick explanation as to why this doesn't work?

Yes, its not possible, unless there is some excellent conducting medium between the batteries for the flow of electrons. :wink:

To set up a potential difference in a battery, it requires a continuous flow of charge. Now if two separate batteries are connected to the load, the electrons from the first battery have no where to go and complete their loop, and are basically just stuck. So, no current.

As for grounding,
http://en.wikipedia.org/wiki/Ground_(electricity )
http://electronics.howstuffworks.com/everyday-tech/question110.htm

Earth here acts as a -huge- conductor(reserve) of electrons, so the circuit is complete.
 
Last edited by a moderator:
Infinitum said:
Yes, its not possible, unless there is some excellent conducting medium between the batteries for the flow of electrons. :wink:

Wait.. So you're saying it is possible? I thought it would be fundamentally impossible...
Fill me in...

To set up a potential difference in a battery, it requires a continuous flow of charge. Now if two separate batteries are connected to the load, the electrons from the first battery have no where to go and complete their loop, and are basically just stuck. So, no current.

This is what confuses me about grounding, it seems as if they cannot complete their loop. Could you elaborate a bit?
 
fletch-j said:
Wait.. So you're saying it is possible? I thought it would be fundamentally impossible...
Fill me in...

It is possible IF you get a way to transfer electrons between the two batteries. That is by a wire, or a medium like aqueous sodium chloride, etc. This is equivalent to just touching the two batteries. Only difference being that you don't physically touch them, you just give them a way of transferring their electrons.

This is what confuses me about grounding, it seems as if they cannot complete their loop. Could you elaborate a bit?
As I said in my above post, the Earth acts as the conductor/reserve of electrons. So electrons from the source can go to and through the earth, just as if it were a wire. Or, if used as a lightning conductor, Earth acts as a reserve (though in the broader sense, a conductor) and takes in all the electrons.
 
Infinitum said:
As I said in my above post, the Earth acts as the conductor/reserve of electrons. So electrons from the source can go to and through the earth, just as if it were a wire. Or, if used as a lightning conductor, Earth acts as a reserve (though in the broader sense, a conductor) and takes in all the electrons.

Ok, so are you saying the electrons just don't return to the power source?
Could you set up a circuit that goes :
[negative terminal of battery] --- [Load] --- [earth]
 
fletch-j said:
Ok, so are you saying the electrons just don't return to the power source?
Could you set up a circuit that goes :
[negative terminal of battery] --- [Load] --- [earth]

Oh no. Not at all. I was just reasoning why grounding works. The lightning conductor case is irrelevant. :redface:

From wikipedia
In electronic circuit theory, a "ground" is usually idealized as an infinite source or sink for charge, which can absorb an unlimited amount of current without changing its potential.

The use of the term ground (or earth) is so common in electrical and electronics applications that circuits in portable electronic devices such as cell phones and media players as well as circuits in vehicles such as ships, aircraft, and spacecraft may be spoken of as having a "ground" connection without any actual connection to the Earth. This is usually a large conductor attached to one side of the power supply (such as the "ground plane" on a printed circuit board) which serves as the common return path for current from many different components in the circuit.

So yes, you do have to return to the power source. The grounding is just the way for it to happen.
 
Ohhh okay!
That clears things up. I was making it too complicated for myself...
Thanks for your patience :P
Have a nice day/night (depending on where you are in the world)
 
My pleasure :smile:

Have a good *insert time of the day here* too. :wink:
 

Similar threads

Undergrad Potential difference between a battery's terminal and Earth ground
  • · Replies 58 ·
2
Replies
58
Views
6K
Undergrad Electric potential and potential difference
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad How a Battery creates a Potential difference in an electrical current
  • · Replies 14 ·
Replies
14
Views
6K
Undergrad Charging Capacitor with one terminal grounded
  • · Replies 16 ·
Replies
16
Views
3K
Undergrad An attempt to understand the associated variable conventions in circuits
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad How is Potential Difference Created across a Resistor?
  • · Replies 21 ·
Replies
21
Views
4K
Undergrad Trying to better understand the physics of electrical earth ground
  • · Replies 18 ·
Replies
18
Views
4K
Undergrad Electric Potential in circuit
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Is the current related to a path or to potential difference?
  • · Replies 4 ·
Replies
4
Views
1K
Undergrad Electric field in a circuit with a DC source
  • · Replies 2 ·
Replies
2
Views
11K