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Quick DC question

hacksign23hacksign23 Posts: 15
edited 2010-08-17 00:15 in Propeller 1
Sorry, I didn't know where to post this, and I usually post stuff here :P

soo...
when a battery is wired up to a... led for example, do protons go through the + terminal, and do electrons go through the - terminal to power up the led?
like does it have two paths, or only one?

thanks.

Comments

  • John R.John R. Posts: 1,376
    edited 2010-08-16 14:01
    I sure hope that protons don't go anywhere.... *

    Electrons flow from the negative terminal, through the circuit, and back into the positive terminal.

    The symbology used in electronic schematics represents "popular current" or something like that, and is really the oposite of the actual flow.

    John R.

    * The number of protons in an atom determines the Atomic Number, hence, if the protons started moving, we'd be making different elements, and that might get a bit "exciting".
  • ke4pjwke4pjw Posts: 1,173
    edited 2010-08-16 14:19
    Electrons travel from the negative terminal of a current source, through your load, to the positive terminal of the current source.

    The opposite of an electron is an "electron hole". As an electron moves from atom to atom within the conductor, "electron holes" are created and filled in the opposite flow. At least that is the way it was explained to me. I very well could be wrong :)
  • hacksign23hacksign23 Posts: 15
    edited 2010-08-16 14:30
    omg -_- i feel dumb. HAHA.
    so only electrons flow, from negative terminal to positive. right?

    then how come a + terminal has ... ex: +5 volts ?
    that means it has too little electrons, so ground balances it, right ._. ?
  • ke4pjwke4pjw Posts: 1,173
    edited 2010-08-16 14:33
    That is correct. An excess of electrons exist on the negative terminal and an excess of "holes" exist on the positive terminal. The potential difference between those terminals is known as electromotive force and is expressed in units of "volts".
  • LeonLeon Posts: 7,620
    edited 2010-08-16 14:34
    Before electrons were discovered, it was thought that current flowed from positive to negative. This is called "conventional" current flow.
  • RaymanRayman Posts: 14,889
    edited 2010-08-16 14:37
    The convention is that current flows from + end of a source to the - end. I believe they came up with that convention before realizing that electrons were the charge carriers in metal. So, electrons go in the opposite direction as current flow.

    In semiconductors, you can have holes, that go in the way you'd think.

    BTW: People make proton currents all the time. If you ionize hydrogen, you make a free electron and a free proton. If you put a big enough electric field on this hydrogen plasma, you can draw proton current. Not something you're likely to do at home though...
  • SSteveSSteve Posts: 808
    edited 2010-08-16 17:38
    Leon wrote: »
    Before electrons were discovered, it was thought that current flowed from positive to negative. This is called "conventional" current flow.

    Apparently it was Ben Franklin's fault: http://xkcd.com/567/
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2010-08-17 00:15
    When flying a kite, in a thunder storm, he probably didn't care which way the shock travelled.
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