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Is electric electrons and protons?

  1. Oct 22, 2009 #1
    In an electrical circuit, I hear a lot about the positive charge drift, but in my mind, I'm sure its only the electrons that actually move. Do protons move in an electric circuit?
     
  2. jcsd
  3. Oct 22, 2009 #2
    No.By convention,we postulate that it is positive charges that move in an electric circuit and create an electric current,thus charges move in the same direction just as the current.
     
  4. Oct 22, 2009 #3

    Integral

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    To the best of my knowledge no one has ever postulated positive charges. In the positive current convention charges (electrons) flow in the opposite direction of current. For the purpose of circuits it simply does not matter which direction you define current flow, as long as you are consistent the results are the same.
     
    Last edited: Oct 22, 2009
  5. Oct 22, 2009 #4
    My thinking is that at a quantum level the protons are actually the material itself, while the electrons are bouncing through the protons.
     
  6. Oct 22, 2009 #5

    f95toli

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    Actually, at the quantum level it is best not to think about the electrons moving either.
    They DO move due to the electric field; but their motion is pretty much random and the average drift velocity is only a few cm per second; much slower than the speed at which the electromagnetic wave travels through a circuit (i.e. the speed of light).
    There are systems where electricity is actually conducted via ballistic particles, but that is an expection and not somethig you find in ordinary circuits.
     
  7. Oct 22, 2009 #6
    In electrodynamics, it is just as valid to think of a current of negative charges moving in one direction as it is for a current of positive charges moving in the opposite direction, the math works the same way.

    The whole negative/positive confusion came from the early studies of electricity and magnetism. Legend has it that it was Benjamin Franklin that defined positive arbitrarily as the charge left on a glass rod after being rubbed with silk. It wasn't until later that people figured out that it was the negative charge that actually moved.
     
  8. Oct 22, 2009 #7

    jtbell

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    From a letter dated Sept. 1, 1747, written by Franklin to a friend in London, and later published in his "Experiments and Observations on Electricity" (1751):

    (page 15 in the book)
     
  9. Oct 22, 2009 #8

    Dale

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    In metals the charge carriers are electrons, but in electrolytes (including batteries) the charge carriers are positively and negatively charged ions. So many practical circuits will have a mix of positive and negative charge carriers. For most purposes the nature of the charge carriers is irrelevant and it is sufficient to just think about the current.
     
  10. Oct 22, 2009 #9
    Post #8 is correct and a good way to think about "current flow". Electrons can slowly migrate in a typical wire based circuit because with conductors of electricity, outer bound electrons are loosly held in place....that's what a conductor means...there are some electrons available for current. In an insulator all electrons are tightly bound to their nucleus and so they are held in place unless very high voltages are applied....

    Wikipedia says it this way under electrical insulators:
    Another important electrolytic environment is sea water (salt water) where all sorts of ions (charged particles) take part in the disintegration of underwater metals on boats. Large ships, for example, have active cathodic protection systems which apply a voltage to parts of the hull because the movement of the ship thru water creates currents harmful to underwater metals in an electrolyte.
     
  11. Oct 22, 2009 #10
    Yeah, Ben Franklin was the man that decided that electrons were to be considered the "negative" charge, and since there weren't any well understood means of finding out which charges were actually moving in circuits, he had a 50/50 chance of making the sign convention simple. Unfortunately, most circuits have negative charge carriers moving. Luckily for us though, a negative charge moving in one direction can be considered as a positive charge moving in the opposite direction (in the case of circuits, at least).
     
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