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Stupid question of the day....

Discussion in 'Electronic Basics' started by AllTel - Jim Hubbard, Jul 30, 2005.

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  1. John Fields

    John Fields Guest

    ---
    Right. That's what the topic is about: galvanic corrosion, and
    which is what all of us, except you, have been talking about.
    ---
    ---
    Crappola. You know nothing about the process, and when you butted
    in with your shit, and with what you think the Navy thinks, you
    thought that "galvanic action" was the right name for what it's
    called. It's not, and now you're trying to cover your ass by doing
    a little semantic "shuffle and smoke" routine. Typical for you, you
    phony piece of shit. I suspect next you'll be off searching the web
    for every possible thing you can find on galvanic corrosion just to
    make it seem like, the next time you post, you knew it beforehand.
    Hey, I'll even _give_ you a hand. Google "electrochemical series"
    and suck on that for a while.
    ---
    ---
    Make a list, motherfucker.
    ---
    ---
    Because you knew nothing about it and couldn't manage to pull your
    head out of your ass? Sounds to me more like reasons for folks to
    plonk _your_ sorry ass out of existence.
    ---
    ---
    The reason I demand proofs from you is because you're a fucking
    liar.

    I'm not, and when I say that something isn't true I can back it up
    even if I don't choose to at the time I said it, for whatever
    reason. The last one had to do with the poster's carelessness in
    not declaring that an electrolyte was needed in order for galvanic
    corrosion to proceed, and I figured that if I gave him a little prod
    he'd figure it out for himself. I was a little surprised that he
    was miffed at not having been given the answer on a silver platter,
    but there ya go...

    See, Tokey, one of the differences between you and I is that I've
    got a solid technical background and can stand my ground without
    having to resort to bullshit tactics, like you do, in order to try
    to blow up my balloon.
    ---
     
  2. Bob Myers

    Bob Myers Guest

    Not at all. You're apparently using a very interesting, albeit
    incorrect, definition of "skin depth." As has already been pointed
    out numerous times, the "skin depth" figure that results from the
    calculations you've been using is where the current density is
    down to about 37% of its "surface" value (not 37% of the conductance
    or loss or any other nonsensical notion that you seemed to think
    in a previous post). There is clearly still current farther from
    the surface than the "skin depth," and it is also clear that the
    density above that value is non-uniform. This IS important,
    and again I would suggest you check the values through an
    actual loss calculation to see just how big the effect can be.

    That comment is particularly ironic, along with:
    given the following:
    Talk about the pot complaining about the complexion of the
    kettle...

    Further nonsense:
    Translation: you didn't bother to run the numbers, or you wouldn't
    be saying something so obviously incorrect. Next time, show your
    work.

    Bob M.
     
  3. Ratio of AC resistance at 60 Hz to DC resistance for 17 mm diameter
    copper wire:

    Going by "High Frequency Resistance", pages 3323-3325 of the 43rd
    edition of the "CRC Handbook":

    They give a formula X=pi*d*SQR((2*u*f)/rho)*SQR(1000)

    u is magnetic permeability, unity for copper.

    rho is resistivity in microohm-cm.

    They simplify this for copper, to x=10*d*.01071SQR(f)

    d is diameter in centimeters, and f is frequency in Hz.

    So, for 17 mm diameter copper wire at 60 Hz this "x" is 1.41.

    Next is a table that gives ratio of AC resistance to DC resistance as a
    function of this "x".

    This table has an entry for 1.4, giving AC resistance 1.020 times DC
    resistance.

    - Don Klipstein ()
     
  4. John Fields

    John Fields Guest

     
  5. Bob Myers

    Bob Myers Guest

    But that wasn't the question. You were responding to a comment made
    in the specific context of gold-on-copper, to the effect that "galvanic
    reaction" was the reason that such a combination wasn't a good idea.
    Sorry, but the "galvanic reaction" of dissimilar metals has absolutely
    nothing to do with the subject at hand.

    There actually very often IS another layer (commonly, nickel) placed
    between a copper conductor and a top protective layer of gold, but
    this has nothing whatsoever to do with a "galvanic reaction" between
    these two metals. (If it did, following the original incorrect response
    on this subject, the problem would then become WORSE due to the
    fact that there would now be two such interfaces rather than one.
    Remember, if you can, that the original comment along these lines said
    that a "galvanic reaction" was a problem between ANY two metals.)
    The reason that an intermediate layer of nickel is often used in this
    case has to do with the fact that, left to themselves, gold and copper
    will tend to diffuse into one another. This causes a problem in
    electrical applications (where gold-plating copper conductors is being
    done to prevent corrosion) primarily on the gold side of things, as
    the copper diffusing up through the gold layer will eventually reach
    the surface and create the very same corrosion problem that the gold
    was supposed to be preventing. Nickel doesn't diffuse into gold
    like copper does, hence its use here.
    My, again with the personal attacks; I suppose in the absence of
    practical knowledge, that's about all one is left with.

    Bob M.
     
  6. TokaMundo

    TokaMundo Guest

    Since a thin round copper wire has a very low emissivity it wont
    give up its heat all that fast. This will mean that your thermal
    gradient won't be as prevalent as you suggest. The proof is when one
    takes a copper wire and places it across a battery's terminals.
    Notice how the entire wire turns a nice cherry red quite evenly, all
    the way up to where it is attached to any form of sinking element.

    The current throughout the wire will be even, and it is that current
    which generates the heat, or more precisely, the resistance to said
    current flow.

    If the wire were giving up its heat real fast, like that of a finned
    heat sink with air passing over it, I might agree. In the case of
    bare copper, however, the temperature throughout the wire is going to
    be very even. Your gradient will be nearly undetectable.

    For a very large diameter copper bus, it MIGHT have a slight
    gradient between the center and the outer surface, but not much. For
    wire, it is as even as even gets.
     
  7. TokaMundo

    TokaMundo Guest

    Actually, it is an oxide inhibitor, and its function is to seal away
    oxygen.

    It too is conductive.
     
  8. TokaMundo

    TokaMundo Guest

    Bullshit. My reference to the Navy being concerned with it proves
    that you are yet again, just being an ass. I see that that is easy
    for you though.

    Galvanic reaction IS the process by which galvanic corrosion occurs.
    Try using facts, asshole.
    Sure I do.
    I didn't butt in, asshole. I called you an idiot, because your
    response was nothing less than idiocy.
    It is more like what I know that the Navy thinks, asshole.
    I never said that, idiot old man. What I said was REACTION.
    Big difference.
    I never said that term, so you are yet again an ass.
    You're full of shit. No semantics about Johnny. You are a piece of
    shit, therefore you must consist of nothing but shit. So far, in this
    thread, you have proven that beyond all doubt.
    More proof. Do you have any facts to contribute, asswipe?
    I have been around more ships than your lard ass has.
    **** off, and die. Suck on that forever.

    Mirror, mirror, little boy.

    Hahahaha... everyone jumped on me ONLY because I called you the
    asshole that you are. They would quickly learn how right I am by
    merely looking at your posting history. Particularly those posts
    where you are an insulting twit, which is quite often.

    You're an idiot that hides behind the fact that you are beyond arm's
    reach, boy.

    No. The fact that you are the fucking troll, boy.
    I could give a shit what others do, but I don't.
    You're a fucking retard. One that is lucky he is beyond arm's
    reach.
    Yes, you are. You are exactly that.
    You called me a liar, and you can't back up a fucking thing, retard
    boy.
    You are the same retarded twit that demands that others do what you
    feel you have a right to choose to ignore doing. Precious!
    Like being a mere insulting asswipe?
    It's not for you to declare someone else to be careless, and then
    justify your own carelessness. Especially when you frame it as an
    insult, which you invariably do.
    You mean like the one I gave you for your spell checker retarded
    behavior?
    I wish you'd go. Straight to hell, dipshit.
    **** you, asshole. Your bullshit enlightens no one.
    That you are a fat, old lardass that is near death, and feels the
    need to "prod" folks. **** off, asshole.
    No. You are shit. You aren't even technician grade, and you copy
    most if not all of the circuits which YOU claim to have designed.
    If only you were within arm's reach, I would prove you so wrong.
    Your ballooned ass is already blown up.... real good...


    You're an idiot. Just like I said.
    You're also retarded. Seek help, asshole.
     
  9. TokaMundo

    TokaMundo Guest

    Hey Bobby... **** you. Filter me like you have already claimed to
    do, you petty asswipe.
     
  10. Some people say that there is no such thing as a stupid question. Obviously
    there seems to be no shortage of stupid answers.

    Bill
     
  11. TokaMundo

    TokaMundo Guest

    The table I saw shows the AC and DC resistance as being exactly the
    same for both.

    Your flaw is where you failed to note the topic given in the CRC
    handbook.

    60 Hz is NOT high frequency... at all.

    Try some calculations at 100 kHz and you'll see that those
    frequencies down near zero (ie 60Hz) yield very nearly nil difference.
     
  12. TokaMundo

    TokaMundo Guest

    As if declaring that someone has "no practical knowledge" isn't a
    personal attack.

    **** off retard. You have social problems.
     
  13. TokaMundo

    TokaMundo Guest

    Yours certainly contributed absofuckinglutely nothing, and would
    certainly fall into the "stupid answer" category.

    You remind me of a Firesign Theatre quote:

    "Who wona second world war.. you so smart?"

    Perhaps, if you are so informed, you should try giving an answer
    that actually has facts in it that are in sync with the topic of the
    thread, not merely its title.
     
  14. The Navy also deals with lots of salt water. ;-)
     
  15. John Larkin

    John Larkin Guest


    There are no stupid questions, only stupid people.

    John
     
  16. Maybe your table rounds? Please cite source as well as I did.
    I did note this, as you quoted above.
    The formulas are functions of wire diameter, wire resistivity and
    frequency, and do not lose validity merely because a thick wire has AC
    resistance greater than DC resistance at a frequency that is easy to label
    "NOT high".

    And as you asked... Ratio of AC resistance to DC resistance of 17 mm
    diameter copper wire at 100 KHz is about 21.5. This does not invalidate
    the calculation for 60 Hz.

    You would have been better off claiming that resistance 2% higher at 60
    Hz than at DC is a negligible increase.

    - Don Klipstein ()
     
  17. Autymn D. C.

    Autymn D. C. Guest

    I'm not a son, you illiterate and uncouth obscurantist troll. I
    already used reason in the proof, which you wilfully ignore. It uses
    maths too, which puts a limiting case on the Lorentz corrections,
    remembering that GR and QM are incompatible. It looks like my other
    replier didn't read it too or he would be forced to agree with me. The
    people here are retards.

    -Aut
     
  18. Autymn D. C.

    Autymn D. C. Guest

    There are stupid questions, those that could be easily found on one's
    own.
     
  19. Autymn D. C.

    Autymn D. C. Guest

    Stop swearing or I'll beat your head in, the part that causes swearing.
     
  20. Autymn D. C.

    Autymn D. C. Guest

    You can't prove anything. You're wrong in everything.
     
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