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Electric Potential & Electric Field

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

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  1. Lorraine

    Lorraine Guest

    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?


  2. 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 and get a decent book on the subject.
    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.
  3. 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

    Mark L. Fergerson
  4. CWatters

    CWatters Guest

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

    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.
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