Electric potential and earth/ground

In summary, the conversation discusses the possibility of creating a circuit between two batteries without them touching and the role of grounding in a circuit. It is determined that a circuit without touching batteries is not possible, and grounding allows for the completion of the circuit by acting as a conductor for electrons. Grounding is also described as an idealized infinite source or sink for charge.
  • #1
fletch-j
19
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!
 
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  • #2
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
 
  • #3
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 [Broken])
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:
  • #4
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?
 
  • #5
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.
 
  • #6
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]
 
  • #7
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.
 
  • #8
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)
 
  • #9
My pleasure :smile:

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

1. What is electric potential?

Electric potential is the amount of electrical potential energy per unit charge at a specific point in an electric field. It is measured in volts (V) and represents the ability of an electric field to do work on a charged particle.

2. How is electric potential different from electric field?

Electric potential is a scalar quantity that describes the energy of an electric field at a point, while electric field is a vector quantity that describes the direction and strength of the force that charged particles experience in an electric field.

3. What is the relationship between electric potential and earth/ground?

Earth/ground is considered to have an electric potential of zero, and all other points in an electric field are measured relative to this reference point. This means that the electric potential at any point on the earth/ground is zero, and any other point will have a positive or negative electric potential value.

4. How does the concept of electric potential apply to circuits?

In a circuit, electric potential is used to describe the difference in energy between two points. This is seen as the voltage difference between the positive and negative terminals of a battery. The flow of electric charge, or current, is driven by this potential difference.

5. How is electric potential related to electric potential energy?

Electric potential energy is the potential energy that a charged particle has due to its position in an electric field. This energy is directly related to electric potential, as the change in electric potential energy is equal to the product of the charge and the change in electric potential.

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