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What is positive electricity?

  1. Aug 6, 2017 #1
    As an electronic engineering graduate, I was taught that positive electricity was the flow of "holes" created by the absence of electrons. These holes and the vector movement are modeled as the "positive" flow of electricity. Why then do I hear experts refer to proton current as positive electricity? Sorry if this question is in the wrong place, I am new to this site.
     
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  3. Aug 6, 2017 #2

    Drakkith

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    In certain situations, such as in electrochemical cells or fuel cells perhaps, there is a very real proton/positive ion current. I believe this current follows all the usual rules for electrical circuits, just like holes do. Perhaps someone with more experience in this area can give you a more in-depth answer.
     
  4. Aug 6, 2017 #3

    sophiecentaur

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    That expression is not in general circulation. How many references can you give for use of the term? Also 'electricity' is a general 'catch all' term for 'electrical power, electrical current or a general study of the whole subject'. Electric Current is a flow of (often just theoretical) positive charges. That is often indistinguishable from negative electrons flowing in the opposite direction. An ammeter in series with a metallic conductor would be aware just of a conventional current. Likewise for a P type semiconductor, the ammeter would just interpret what we call 'holes' as a current AND for a flow of positive ions, as mentioned by Drakkith, above. The charges actually passing through the ammeter would (almost certainly) still be electrons.
    It is wise to avoid worrying too much about what's actually 'carrying' the current unless you are in the rare situation of actual positive charges. Even Holes are only fictitious entities; they don't get out of the end of the semiconductor.
     
  5. Aug 10, 2017 #4

    jim hardy

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    Amen.

    Holes are atoms in the silicon crystal lattice with one too few valence electrons. They are called 'acceptor' dopants.
    When an electron attaches to an acceptor atom it leaves a hole wherever it moved from.
    https://people.eecs.berkeley.edu/~hu/Chenming-Hu_ch1.pdf
    upload_2017-8-10_1-8-25.png
    That author uses a 'bubble in liquid' analogy
    i prefer the "Chinese Checkers" analogy where it's the marbles that move not the holes in the board.

    upload_2017-8-10_1-12-11.png


    In a transistor it's the electrons that move not the atoms.
     
  6. Aug 10, 2017 #5
    As Drakkith said you do get currents due to the flow of positive ions for example in proton accelerators and mass spectrometers.
     
  7. Aug 10, 2017 #6

    sophiecentaur

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    But you have to go to an awful lot of trouble to make that happen. Afaik, there is no 'natural' process that will resolve a plasma (frequently occurring mixture of + and - ions) into the separate constituents. Even in a plasma, the electrons are so much more mobile and have so much lower mass that it is they, and not the + ions that are responsible for carrying any current (discharge tubes etc.). The + ions cannot get out of the end, via the electrodes.
    It is true, of course, that in an electrolytic cell, the + ions actually move and deposit on the Cathode but there will be an equal and opposite flow of - ions/ electrons on to the Anode. But that is not a Solid State thing and doesn't 'support' the idea of real holes moving.
     
  8. Aug 10, 2017 #7

    ZapperZ

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    First of all, you need to provide a more definitive source rather than just "I hear experts...." Experts often use loose and sloppy terms when talking with other experts because they all know exactly what they are talking about, similar to physicists talking about "masses" in units of eV or MeV. So what you are worried about could be a moot point if they are talking about something specific that they all understood.

    But more importantly, this "proton currrent" needs a proper context. Certainly, there is no such thing as a "proton current" in an ordinary conductor. But there ARE proton currrents at the LHC at CERN and at various spallation neutron sources around the world. Are these experts then talking about such things? This is why I said that the CONTEXT is important, and why proper citation of sources is important.

    Zz.
     
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