Conventional Current and Electron Flow?

Discussion in 'General Electronics Chat' started by immortalacorn, May 25, 2011.

  1. immortalacorn

    Thread Starter New Member

    May 19, 2011
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    I've been quite confused about this. I understand conventional current is the opposite of electron flow, but how does all this work out in a schematic?

    [​IMG]

    Assuming I have the capacitor in the correct way, this should make sense if you read it with conventional current. But if you were to actually make a circuit according to this, wouldn't it be dangerous? If electrons are really flowing in the opposite direction, wouldn't this be breaking a few safety rules?
     
  2. #12

    Expert

    Nov 30, 2010
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    It's all conventional.

    Conventional current says that current flows from positive to negative, but I say somebody named the charge on an electron wrongly, and that's a convention, too!

    People draw schematics with positive at the top and work with positive numbers as much as possible because its easier. If the electron was named as positive, conventional flow and electron flow would be the same and we'd use a lot more pnp transistors!
     
  3. immortalacorn

    Thread Starter New Member

    May 19, 2011
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    But how can you prevent mixing up parts? Obviously, some components are picky and will only accept current in a specific way. When building a circuit that uses conventional current, are you suppose to flip all the components(or the battery) around?
     
  4. #12

    Expert

    Nov 30, 2010
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    No, the components don't flip around because you think differently. Electrons still flow from the ground symbol to the positive rail when you are thinking, "positive voltage drops across the collector resistor".

    It's only a way of thinking. Electron flow works for me when I get confused with conventional flow because conventional is a convention, and electrons seem more real to me, even if calling them negative is also a convention.

    edit: PS, your capacitor is backwards. The curvy line always faces the positive voltage.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    If you read the book, or the notice in Feedback and Suggestions, it is explained simply.

    Conventional flow vs Electron Flow

    In a nutshell, when Ben Franklin first stated his theory of electricity, he got it wrong. There was no concept of the structure of the atom, or electrons, so who could blame him? He flipped a coin.

    But that was almost 200 years ago. For 150 years his theory reined supreme, unchallenged. A lot of textbooks were written, and a lot of scientific papers too.

    Then, in the early 20th century, the world of the small started giving up its secrets. We now understand atoms, and electrons, and much more. The old guy still deserves heaps of credits, but the theory has been revised. It had to be, things like tubes (aka valves) simply did not work under the old theories.
     
  6. immortalacorn

    Thread Starter New Member

    May 19, 2011
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    So, what if a circuit used a diode or something. Diodes will only send current 1 way. If you read a schematic with conventional current, wouldn't the diode be facing away from the direction your going?

    [​IMG]
     
  7. #12

    Expert

    Nov 30, 2010
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    Yes. The diode in that picture is wrong. The plussy things always go in the back of the triangle and come out the bar end. The minusitive things always go in the bar end and come out the back of the triangle.

    You can think in terms of electrons, or holes, or plusitrons or minusatrons, or Leprechauns. Just pick one. When you get good at that, try the other way of thinking. Shouldn't take more than a few years.
     
  8. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    If you have a positive voltage and a diode -- the diode should 'point' at ground in order to conduct electricity(either kind ;) )
     
  9. Wendy

    Moderator

    Mar 24, 2008
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    The arrow on transistors and diodes points to the negative, this conducts.
     
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