Electric Potential & Electric Field

Discussion in 'Misc Electronics' started by Lorraine, May 23, 2005.

1. LorraineGuest

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?

Lorr

2. Vidar LøkkenGuest

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.
http://www.amazon.com/exec/obidos/search-handle-form/104-8338403-6128734
That search turned up a lot of titles, and you can even have a look at
I guess that google might turn up a few thousand results for basic
electronics too, if you don't want to buy a book.

3. Mark FergersonGuest

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.

but you really ought to crack a text or three for more in-depth
information.

Mark L. Fergerson

4. CWattersGuest

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

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

http://whatis.techtarget.com/definition/0,,sid9_gci752086,00.html

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.

5. R. Steve WalzGuest

------------------------
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.