Joule's Law in the E-Book

Discussion in 'Feedback and Suggestions' started by retched, Jan 28, 2010.

  1. retched

    Thread Starter AAC Fanatic!

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    http://www.allaboutcircuits.com/vol_3/chpt_3/11.html

    States:
    Like any semiconductor device, the zener diode is sensitive to temperature. Excessive temperature will destroy a zener diode, and because it both drops voltage and conducts current, it produces its own heat in accordance with Joule's Law (P=IE). Therefore, one

    I may be overlooking something but I've known Joule's Law as H = RI^2
     
  2. jpanhalt

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    E=RI

    That's too short, so here are some more words.
    John
     
  3. retched

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    So the E-Book is wrong and I am wrong?

    From Encyclopedia Britannica:
     
  4. Wendy

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  5. StayatHomeElectronics

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    Both the ebook and you are correct.

    P = I*E -- power (dissipated as heat) equals current multiplied by voltage.
    E = I*R -- voltage across an element is current multiplied by resistance.

    substitute E back into the power equation

    P = I*(I*R)
    P = I^{2}*R = RI^{2}
     
  6. retched

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    If it confused someone of my caliber and expertise, It could also confuse a third grader.

    It was just a note, but it seemed like a error to me. Seeing a formula I usually equate to Ohms Law with Joules name next to it, threw up a flag. I thought it was a case of the missing exponent.


    Thanks for clearing that up.
     
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