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Thread: question about laser diode protection

  1. #1
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    Default question about laser diode protection

    i want to make my own built using a aluminium diode housing and a 1.8W M140 445nm laser diode, Oclaro 700mW 638 Diodes (HL63193MG) and a N520 1W 520nm Green Laser Diode all from DTR
    now i was wondering if i mount these diodes in the aluminium diode housings on a aluminium base plate do they need any electrical protection?
    or is it already enough if the base plate is connected to ground?

  2. #2
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    You'll want to add Lasorbs to each of your diodes for static electricity protection. Pangolin sells a wide array of them specialized to the different kinds of diodes. Spending ~US$12 to protect a $180 diode just makes good sense.

    There is a diagram and tutorial that Bill Benner wrote for projector wiring. Its somewhere in the PL forum here, but you can also get it from his book which is available on Kindle for $1.

    Happy building!

    -David
    "Help, help, I'm being repressed!"

  3. #3
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    is the lasorb the only pre-caution? because i have seen lots of modules without lasorb's including kvant's
    sometimes i also see some kind of layer between the diode mount and the base plate, i guess this is some kind of material that electrically isolates the diode mount but still transfers the heat, what kind of material is this?

  4. #4
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    The isolator is a thermal pad like this one. Thermal pads prevent current from moving between the diode mount and the optic plate. Note that this requires you to not short the connection with a metal bolt to fasten the mount to your optic plate. You need to isolate the bolt as well or use a nylon one.

    This said, you generally only do this when you have a case-positive and sometimes case-negative diode. You don't see case-positive or case-negative diodes very often in the type of build you are doing. They are more common for older red diodes and IR diodes. All of the diodes you listed appear to be case-neutral, so you don't need to use thermal pads.

    Lasorbs are commonly used with higher-end builds, but not mandatory. They simply protect your expensive diodes from static discharge. I would definitely use one for your US$180 green diode. The US$26 blue diode is up to you. I use them on all diodes in my builds. If it saves me from having to replace one diode and realign, they are well worth the extra investment.

    -David
    "Help, help, I'm being repressed!"

  5. #5
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    Thanks for the help so far, i did check the lasorbs and was curious about something.
    wouldnt a schottky and zener diode both parallel to the diode act the same as the lasorb?

  6. #6
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    Sure thing, John. I am an electrical engineering dropout turned accountant, so I'm the wrong person to ask about electronics. However, the accountant in me can tell you that for $8, saving time (making your own or replacing a diode), getting a well-tested product, and getting some peace of mind is a very good bargain.

    Pangolin has a few videos on their website about the Lasorbs that may provide you with a better understanding of what they are capable of.

    -David
    "Help, help, I'm being repressed!"

  7. #7
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    Who has these for sale in USA? Didn’t see them on dtr site.

  8. #8
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    You can get them directly from Pangolin's website.
    "Help, help, I'm being repressed!"

  9. #9
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    You have buy ten of each. Only need three

  10. #10
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    Quote Originally Posted by kecked View Post
    You have buy ten of each. Only need three
    Really? I've bought less than 10 of each, although I've bought at least 10 in total each time, I think. Usually along with some other stuff.

    In any case, you can get reds and blues from Aixiz on Fleabay for $11 each + $2.50 shipping. I'll sell you a green if I have a spare (I think I do) for what I paid for it. Green and 405nm diodes are the most sensitive in my experience, so I'd definitely get a green Lasorb. Just PM me.

    -David
    "Help, help, I'm being repressed!"

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