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Thread: 445nm MOST Heat?

  1. #1
    Join Date
    Jul 2006
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    Default 445nm MOST Heat?

    I have a weird request. This is not for Light show use. It is for a proof of concept design for a military application.

    I need to know which diode, (power/wavelength) produces the MOST heat from a single diode under normal operating conditions. I understand that the diodes are all mounted in modules and mounts. And these are obviously PURPOSELY designed to dissipate heat produced. But a single diode, lets just say (theoretically) mounted in a relatively simplistic module that dissipates ZERO heat produced (I know- completely silly.) What diode would this be?? I am assuming one of these monstrous 445 diodes? 4-5 Watt range??

    Diode must produce a lot of heat
    Diode must be driven under normal current

    NDB7875 seems like a pretty safe choice. Any other diodes out now that I may be unaware of??

    Thank You.

    -Marc
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  2. #2
    Join Date
    Feb 2011
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    New Hampshire
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    Default

    The blue diodes are at best 30% efficient (70% heat) and this is lower than the reds and these are lower than the 808s, 9xx etc and so I think the greatest heat will be generated by the new 7-??? watt V1 blues. More of these will be available from DTR. All ofn these diodes are less efficient as the temperature rises and the thermal conductivity of the metals drops as well. This second point is not trivial as the temperature near the junction will be significantly higher than that measured at say the bulk mount.

    Even though you said "under normal operating conditions", I think applying extra cooling or driving them harder than recommended will produce the same relative effects and so the choice would not change.

    I am assuming you are not asking about diode bars and the like which obviously can generate hundreds of watts of waste heat. These are not a "single diode".

  3. #3
    Join Date
    Dec 2007
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    Default

    Depends what + how you are driving.
    [Voltage (V) x Current (A)] - Output power (W) = Heat Dissipated (W)
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  4. #4
    Join Date
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    Default


    Quote Originally Posted by danielbriggs View Post
    Depends what + how you are driving. !!!!! !!!!!!
    [Voltage (V) x Current (A)] - Output power (W) = Heat Dissipated (W)
    Jesus Dan .... That's really really ...........profound! Click image for larger version. 

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    But to simplify
    Backput (lectric) = Middleput ('eat) + Frontput (lyte) Click image for larger version. 

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    Cheers
    Last edited by catalanjo; 06-25-2015 at 13:30. Reason: Bare in mind that in UK we all drive on the wrong side NOT on the right side!!

  5. #5
    Join Date
    Dec 2007
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    Default

    Quote Originally Posted by catalanjo View Post
    Jesus Dan ....
    But to simplify...
    Just don't hit 88mph!
    - There is no such word as "can't" -
    - 60% of the time it works every time -

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