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#12 solid wire

Discussion in 'General Technical Questions and Answers' started by WB7DMX, Feb 1, 2006.

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  1. WB7DMX

    WB7DMX Guest

    take a pice of #12 solid wire excatly 1" long

    1. resistance = ?

    2. inductance = ?

    3. capactance. = ?

    who can answere the above ?
  2. KE5FRF

    KE5FRF Ham Member QRZ Page

    Well, I must admit, I'd have difficulty with the capacitance and inductance, though I know that nominal amounts are present even with straight copper.

    But, the resistance is easy. .00187 ohms

    Also, 308.7 feet would come out to one ohm I believe. this is all at standard room temperature, because temperature effects resistance in a linear manner.
  3. WB7DMX

    WB7DMX Guest

    correct, thats one , and the most simple one too.
    just look it up and then devide.
    also it is needed to get the other two.

    and i'll give you all a hint, you also need to know the circularmills to do the other two.
  4. KE5FRF

    KE5FRF Ham Member QRZ Page

    LOL, I'm not an engineer, just a repair guy. I have a motto, remember the usefull stuff, and forget the rest, or you'll be too bogged down with information. In other words, I've never taken wire impedances into account with my work.

    BUT, I'm very interested and would like to see the answer. So, I'll shut up and see if a REAL electronics expert can tackle the answer, and perhaps I'll learn something new. [​IMG]
  5. WB7DMX

    WB7DMX Guest

    I belive the formula for working it out is in the hand book
  6. AL7N

    AL7N Ham Member QRZ Page

    1. damn little
    2. damn little
    3. damn little

  7. WB7DMX

    WB7DMX Guest

    yes it is in the nanonano area and I might say it is a text book type question, and one I will always remember, it took me 3 days to get the answer correct.

    I really don't care if anyone can find the correct answer.
    but I was given that same question in a test while I was taking a course from
    capitol radio engineering technology 30 yrs ago and it does use the same basic standard formulas.
    all I wanted to point out is that something so small does have all the characteristics and will have a effect in a tuned circuit
  8. K7JEM

    K7JEM Ham Member QRZ Page

    How can you calculate the capacitance of a piece of wire, if the other "plate" of the capacitor is not specified? It all depends on it's distance from, and the size of, the other conductor forming said "capacitor". I assume the dielectric will be air.

  9. WB7DMX

    WB7DMX Guest

    I can't explain it to you so that you could understand it or anyone else for that matter but its kinda like this,
    there is a capicatance from the flat surface on one end of the wire to the flat surface of the other end, its almost impossible to picture this when the two ends are connected together, you got to remember that there is resistance in the wire and that is what separates the two ends, so the fact that there is capicatance there can be calculated with the correct formula, it is so small that it cannot be measured, but it does exist. if you were to research this out, you will find the correct formula to do this.
    as stated it is a text book type of question, that is, it is a question that was in a book I was studying 30 years ago, and I had to do the math with pencil and paper so that the instructor could see how I came up with the answers to all 3 questions, and the formulas were in the book.
    the object of the question was two fold.
    1, so show that they do exist.
    2. to teach to do the math correctly using the powers of 10 and logarithm, as applied when using a slide rule.
    wish I still had the book today so that I could show you the formula to do it.

    I asked the same question as you did when I first seen the question, and the math proved it true.
    that is why I will never forget that a small pice of wire does in fact have inductance and capicitence
  10. AG3Y

    AG3Y Guest

    Don't get a piece of wire suspended in infinite space, confused with a similiar piece of wire surrounded by other conductive material.. often referred to as "stripline" electronics.

    Here is a good page about that Stripline calculations

    Have fun ! 73, Jim [​IMG]
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