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Best heat sink compound?

Discussion in 'Electronic Repair' started by DaveC, Dec 1, 2003.

  1. DarkMatter

    DarkMatter Guest

    I'm sorry, but those of use that understand what we are doing do not
    design a 200W transistor into a 200 W circuit application.

    One should always use a device at an industry accepted full load,
    full duty cycle design point. The device IS capable of operating at
    the maximum rating, but the headroom is their for reliability reasons,
    pulse conditions, etc.

    So, yes, understanding what I am doing means that I would use my 30W
    IC amp at 10W or so, and use that to pump my large power devices, and
    only utilize THOSE at a power level much less than that at which they
    are rated. For caps, it can be as high as twice the voltage, for
    other components... say power resistors, it is around half. The heat
    generated by a 25W resistor AT 25W is far far too high to have it
    contained in a rack chassis. Pumping only 12W thru the "25W" device,
    however, makes the heat it exhibits much more manageable.
    Got clue?

    For you not to know that is quite a tell.
  2. DarkMatter

    DarkMatter Guest

    No shit.
  3. DarkMatter

    DarkMatter Guest

    You are a dipshit. You pull this crap often where you act as if you
    know someone, or know how much they know, or what they do. You do
    not. You are clueless.

    We are finishing a 200W, 1500V 0.002% regulated, 10mV ripple
    supply. Auto shutoff upon shorts, etc. etc. etc.

    I'll bet you couldn't manage that in ten years "try a bigger fan
    time" We did it inside a few months.

    BTW, the main transformer in this design is huge toroid.
    It is a linear design. The ripple cannot be met via switched modules,
    nor the voltage regulation.
  4. John Larkin

    John Larkin Guest

    You're certainly right there. Sometimes I design a 200 watt part to
    dissipate 1000 watts.
    Sorry, I don't follow rules, I make rules.
    Gosh, you almost make me embarassed to cash all those checks people
    keep sending us. Almost.

  5. John Fields

    John Fields Guest

    No shit?


    " The conductivity, and efficiency of the sink to carry off the heat
    is far more important. " belies your claim of a grasp of the obvious
    before the obvious was presented to you. That is, the conductivity and
    efficiency of the heat sink are unimportant if the hot device can't be
    coupled to it satisfactorily.

    What I think would be interesting would be for you to calculate the
    differences in case temperatures between two TO-220 devices dissipating,
    say, 10 watts; one sitting on the best SIL-PAD you can find and one
    sitting on a patch of anodize about half a mil thick, both on otherwise
    identical heatsinks. Then come back and defend the SIL-PAD.
  6. John Larkin

    John Larkin Guest

    No? I thought that was what Dark Matter was.

  7. DarkMatter wrote...
    Maybe, and best wishes for the success of your interesting project.

    I often use Silpads and other such - very convenient. But in the
    end the hard reality as stated by the two Johns wins, big time. :>)

    - Win

  8. DarkMatter

    DarkMatter Guest

    And all you idiot fucks wonder why I call you retarded.

    That was a perfect example of why.
  9. Rich Grise

    Rich Grise Guest

    Yeah, speaking of TP. The guy who buys stuff for the shop was
    bitching the other day about how we'd gone through 8 rolls of
    TP in a week! I wanted to say, "Of courss. Everybody knows
    companies are a major source of free stuff!" But I held my
    tongue. But I did look at his 12-pack or whatever, and it
    was 150 sheets per roll! That's about enough for 6 wipes!
    And it's the thick crap, like wiping with a pillow. I like
    the industrial-grade cheap stuff too - 1000 sheets/roll,
    and it's got a texture, so you know it's wiping, and not
    just sliding around feeling comfortable. :)

  10. John Larkin

    John Larkin Guest

    No, I don't wonder about that. What I do wonder about is that, since
    you don't like anybody here, and nobody here likes you, and you never
    ask questions, and you're always wrong, why are you here?

    Really, seriously, why?

  11. jriegle

    jriegle Guest


    all this "wiping" talk!

    Long live the bargain brand TP. It doesn't clog up the pot either! (I have
    to wipe a lot because I'm so full of sh!t)
  12. Ian Stirling

    Ian Stirling Guest

    I dunno, I quite like him, he's funny.
    He's simply not up to the class of a decent net.kook though.
    Maybe when his subscription to "Wacky invention that will revolutionise
    fissiks" comes in he'll get better.
  13. DarkMatter

    DarkMatter Guest

    TMI... TMI.... T M I !!!
  14. DarkMatter

    DarkMatter Guest

    Now, if only you could get Larkin's lame ass to figure out that he
    is full of shit as well, we'll have gotten some work done here besides
    just discussing feces. Instead, we discuss the feces that spews the
    feces. look for "Funny Music, and Films" Get
    number 4 of 6. Not my posts.
  15. DarkMatter

    DarkMatter Guest

    Sorry, dipshit, but I have no such machinery in the works. I am far
    above the ilk that has such contrivances as well. They have NO class.
  16. DarkMatter

    DarkMatter Guest

    That won't cut it with UL, or CE if isolation is involved. A Hard
    Anodized aluminum surface is quite porous to prying, highly energetic
    electrical field pressure. I would want a bona-fide barrier there,
    and so does the cert labs. I'll bet the hi-pot on such a surface is
    quite low for prying electrons, regardless of what some ohm meter and
    a simple probe declares.
  17. John Larkin

    John Larkin Guest

    Neat trick, snipping half a paragraph and criticizing what's left.
    Who's going to get shocked by touching a grounded heat sink that's
    bolted to the chassis?

  18. DarkMatter

    DarkMatter Guest

    Who said that it was or had to be grounded? Doesn't matter anyway,
    they, and any good designer would want any elevated voltage node
    isolated, and that better than the isolation provided by some
    anodization of some rarely controlled well enough thickness.

    Whether it is at ground or not isn't the issue.

    The practice is verboten in many circles.

    On conduction cooled modules, typically the case is also the heat
    sink for one or more devices inside. It needs to be isolated.
    Period. I don't care what you say. Plastic devices used in the
    design would allow for an exception, but our mil/rugged units don't
    use those packages, and it can't be changed to them.
  19. Never had that problem here using it for more than 4 years on several
    hundred CPU's and chipsets
  20. ok... on a PIII rated at 133 mhz FSB, I can run it at a 168 mhz FSB
    with Arctic Silver... With the white silicone, I can get no more than
    147 mhz...
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