Electric Potential & Electric Field

Voltage is said to be the difference between the electric potential between two poles of a battery. What is the relationship between electric field and electric potential at the poles. Is there a difference in the electric field between the two poles?


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This might sound harsh, but this group is here to _discuss_ electronics, not to teachs you the basic of electronics. This, google, or a book can do. I suggest you drop by amazon.com and get a decent book on the subject.

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That search turned up a lot of titles, and you can even have a look at the book before buying it. I guess that google might turn up a few thousand results for basic electronics too, if you don't want to buy a book.

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Vidar Løkken

You're very confused, but apparently you already knew that.

Electrons "desire" to be as far away from each other as possible, and express that "desire" as a force they exert against each other; that force reaches out through space no matter how far apart two electrons may be. One way of describing this is to call it a stress in the space between electrons.

We call that spatial stress a "potential field" because at any point in the space betwen them, there's a potential value of force you could measure on an electron inserted at that point. The word "field" is a mathematical term for the gradual change in values from point to point, and it has singularities (maximum/minimum values) at certain points like where the most or least electrons are which are also called "poles".

Since the force acts on the electric charge on electrons and not their mass, it's assigned values in volts.

So, each point in the field can be assigned a "voltage", including two points at different distances from an isolated electron.

When you assemble a battery (chemically take electrons from _here_ and put them over _there_), you will naturally wind up with two poles and a field between them.

That's a fair first approximation to an answer to your questions, but you really ought to crack a text or three for more in-depth information.

Mark L. Fergerson

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Mark Fergerson

Hi Lorraine.

Keep asking those questions! We won't always have the time or the ability to answer (we aren't all professional teachers) but how else can one learn. You planning to study electronics at college or? My first electronics text book was published by Ladybird. Sadly I don't think it's printed anymore.

Not just two poles of a battery. Any two points...

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Well an Electric field exists _between_ the poles. I mean in the space between them physically.

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Imagine two large sheets of metal seperated by 1 meter. Connect each plate to one terminal of a 9V battery. The field in the gap between the plates would be 9 Volts per Meter. If both plates are the same shape then the field near one plate will be similar to the field near to the other.

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------------------------ You're full of shit, Vidar. YOU just don't know the answer so you're posturing, a common ploy to try to gain stature illicitly on a group for a newbie like you.

-- The generalized factor-label difference between potential and field should be understood basically thus:

Force between charges is expressed as K*Q1*Q2 / R^2, where K is a constant having a factor label required to make Q^2/R^2 have the units of force in Newtons, where K's value is 9 x10^9 N*m^2/C^2.

Electric field is defined as Force per charge applied to a tiny test charge Q2 so that E-Field F/Q2 = E = K*Q1 / R*2

So Field is a way of specifying the force per charge a field produces.

Now, another useful expression about a Field is the energy per charge, and that is called potential.

And just like the energy between to charges is given by PE = K*Q1*Q2 / R , so also can the potential, the energy per charge offered by this field be written: PE/Q1 = V = K*Q1 / R .

So, since: E-Field = Force(Newtons)/Charge(Coulombs), And Potential (Volts) = Energy(Joules)/Charge(Coulombs), Then since Force(Newtons) * Distance(Meters) = Energy(Joules), Then E-Field(Newtons/Coulomb) * Distance(Meters) = Potential(Volts) And KineticEnergy(Joules) = Potential(Volts) * Charge(Coulombs)

Electric Field vs Potential then can be described by saying that Potential(Volts) between battery terminals implies an E-Field that depends on the distance traveled in a conductor between them, so that EField = Potential/Distance and the EField can be expressed in Volts/Meter.



-Steve Walz  rstevew@armory.com   ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!!  With Schematics Galore!!
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R. Steve Walz

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