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Thread: Knife edging & driving multiple diodes with 1 driver

  1. #1
    Join Date
    Nov 2015
    Location
    England
    Posts
    30

    Default Knife edging & driving multiple diodes with 1 driver

    Hey all so I am doing another build - initially I thought red would be too expensive but upon review it looks like getting red in this system may be possible on my always modest budget.

    I should explain my previous experience is all with single mode, low power stuff. So I've never really had to delve into knife edging or multimode diodes before.

    I have a DPSS green with a rather large output - about 5mm diameter - and the divergence is ok - so I want to center my build around this. The idea being for outdoor beams.

    I looked online and found this: http://www.ebay.co.uk/itm/Knife-Edge...MAAOSwuMZZNDE-

    I am thinking combining this with Sharp 700mW 638 Diodes (GH0637AA2G) from DTR - they are only $28 each - mount them - and it's possible to get my required >2W of red for under £200 which is really good.

    But I am thinking this is too good to be true - how do I drive these? Drivers are expensive.

    Can I drive these in series? Do I need anything extra? If I chain all 4 together in series and supply 12V to my driver (for example http://www.ebay.com/itm/6-5A-Laser-D...-/141817972786) - the diodes require up to 2.8V - perhaps I can supply 15V to the driver or even 24V to be safe - then set the current pot to 1 amp - how safe is this setup? What could go wrong? If one diode dies, will they all die? Is this driver safe to run at 24V if I have active cooling on the MOFSET?

    How do I correct a knife edged beam? What am I trying to change the beam from and into? A rectangle into a square, then into a circle? I know I need prisms, but where do they go in the setup?

    How large/clean/divergent will the final beam be? Is this too good to be true? Why do suppliers ask for four figures for similar amounts of power when in theory I could do this for under £400 including corrective optics?

    Thanks all

  2. #2
    Join Date
    Mar 2015
    Location
    Cambridgeshire, England
    Posts
    478

    Default

    Plenty of options, Phil (phritzler) does various drivers including multi output versions, have a look here for example.

  3. #3
    Join Date
    Nov 2015
    Location
    England
    Posts
    30

    Default

    Quote Originally Posted by NobleGas View Post
    Plenty of options, Phil (phritzler) does various drivers including multi output versions, have a look here for example.
    Interesting - I hadn't considered multichannel as I didn't know there were any available to us hobbiests and I'm not experienced enough to make my own driver. Do you think it is a safer option?

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