Chicken or Egg question

Discussion in 'General Electronics Chat' started by spkwc, Jul 20, 2009.

  1. spkwc

    Thread Starter New Member

    Jul 20, 2009
    I'm just learning electronics and have a question analogous to did the chicken or the egg come first. When voltage is produced by a generator are electrons also produced? When I plug the cord into a generator the electrons have to come from somewhere.

    Thanks in advance.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    No, the electrons are always present in the conductors. There are just as many electrons in a copper wire that is just sitting there as in one actively acting as a conduit for current.

    The circuit is always closed, meaning the electrons have a closed path to follow, so none are lost or gained.
  3. someonesdad

    Senior Member

    Jul 7, 2009
    A voltage (potential difference) is produced whenever electrical charges are separated (ignoring changing magnetic fields for the moment); it takes energy to separate those charges. The charge carriers in matter (electrons) are always present so, unless one wants to get into cosmological considerations, it doesn't really make sense to worry which came first. Like love and marriage, you can't have one without the other. (OK, I agree, that's a crummy analogy. :))
  4. loosewire

    AAC Fanatic!

    Apr 25, 2008
    You have a still calm lake,you drop a rock In the lake,
    you see the ripple's of energy. The lake will still be there
    after the ripple's sub side. Another point of view.

    AAC Fanatic!

    May 26, 2009
    Remember that energy cannot be created or destroyed. Although this doesn't seem to apply in the quantum world.
  6. Ratch

    New Member

    Mar 20, 2007

    Actually, it takes energy to gather like charges together because they repel one another, and are only too happy to get as far as they can away from each other. The energy it takes to gather them together divided by the number of charges is the energy density of the charge. Another name for that is voltage. In MKS units it is joules/coulomb.

  7. hobbyist

    AAC Fanatic!

    Aug 10, 2008

    Excellent analogy, for his question.
  8. studiot

    AAC Fanatic!

    Nov 9, 2007
    I do wish teachers would cease introducing electrons at such an early stage when discussing electricity.

    In my view it only serves to confuse; it certainly raises more questions than it answers.

    We cannot see electricity. We cannot see the wind. But we happily handle a basic practical appreciation if how the wind functions without any mention of fluid mechanics or the Navier Stokes equations.

    Why can't we start with an equally simple version of electricity?
  9. Externet

    AAC Fanatic!

    Nov 29, 2005
    Last edited: Jul 20, 2009
  10. someonesdad

    Senior Member

    Jul 7, 2009
    Hi, Ratch:

    It's probably not appropriate to get into the physics of charge behavior, as the OP mentioned he is just beginning his studies. He'll get all he needs when he takes his basic physics, E&M, and Electrons in Solids courses. But it is a bit of a pedagogical problem in how to expose enough without giving too much...
  11. count_volta

    Active Member

    Feb 4, 2009
    What you need to understand is free electrons. Electrons aren't produced. God made them and put them into orbit around the atom, just like he did with the planets.

    Metals have electrons in the outer orbit of the atom that can leave the atom. Since they have the ability to leave they are free electrons. When those free electrons feel a positive charge, they leave the atom and move in a current. That is electricity. That is what happens in a battery.

    A generator does something different. Without getting into weird quantum mechanics and such, there is a phenomenon that exists in nature. You move a magnet past a coil of wire and the free electrons in the outer orbit of the atoms that make up the coil of wire begin to move. Different reason than the battery, but its still electricity.

    Take a look at my website which still needs a lot of work and updating, but it explains everything. I need to work on the graphics.

    That Bill Beaty website is also priceless. Especially his explanation of transistors.
    Last edited: Jul 20, 2009