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1,6W 525nm green laser diode

Alaskan

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One? Just one? Hell no, ten!
 



Alaskan

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Knife edged

That is the idea. I checked with a seller on ebay who FAC corrects diodes asking if she could get the NDG7D75T to correct and this was her response:



I need to know where the knee is for that much power as well as the diode temperature to determine whether to push them that hard, even if they will produce that much output.
 

skijohn

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I bought an NDG7475 1W+ 520nm Green Laser Diode From DTR Monday and tracking shows it's in town...
 

Alaskan

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Can’t go wrong with either DTR or that diode. Those diodes will produce at least 1.3 watts out of an AR coated collimator lens. Much depends upon the heat sink to keep it cool enough to have a long life.
 
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Peter Zeboroff

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For those who may not know, sabzh21 seems to have two of these 525nm 1.6 watt green laser diodes and he is asking $142.00 U.S.
 

Alaskan

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The spec. sheet says max 2.3 amps, but you know what we do, we run them higher. Someone may have already posted where the "knee" is at for those diodes (it can vary some between individual diodes of the same type), or the place where increasing the current no longer produces a linear increase of output, but I have not seen it yet.

Testing to find where the knee is at is just to find a fairly safe place to operate it at, you don't want to set the current on the diode where increasing it no longer produces a linear smooth increase of output, keep it below that by some healthy percentage. Anyone have a rule of thumb for that?

You can go to the DTR LPF google store and see photo's where he has tested many diodes to find the knee showing both the voltage and currents throughout the test, that should give you an idea, then look where he recommends to run the diode at to extrapolate a percentage which may vary between models, I don't know.



Link to .pdf I saved on my site:
I tried to get that diode direct from the manufacturer, they won't sell to me :( Did you buy through that Japanese listing?

This has been the case for most of our diodes, you have to get them through some other source they can leak to us through.
 
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Miya

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Oh!! Good. I want set 2.5A ~ 2.8A with G2 or G9 lens



The spec. sheet says max 2.3 amps, but you know what we do, we run them higher. Someone may have already posted where the "knee" is at for those diodes (it can vary some between individual diodes of the same type), or the place where increasing the current no longer produces a linear increase of output, but I have not seen it yet.

Testing to find where the knee is at is just to find a fairly safe place to operate it at, you don't want to set the current on the diode where increasing it no longer produces a linear smooth increase of output, keep it below that by some healthy percentage. Anyone have a rule of thumb for that?

You can go to the DTR LPF google store and see photo's where he has tested many diodes to find the knee showing both the voltage and currents throughout the test, that should give you an idea, then look where he recommends to run the diode at to extrapolate a percentage which may vary between models, I don't know.



Link to .pdf I saved on my site:
I tried to get that diode direct from the manufacturer, they won't sell to me :( Did you buy through that Japanese listing?

This has been the case for most of our diodes, you have to get them through some other source they can leak to us through.
 

Alaskan

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Of course, you need to run the current up while measuring the output power, once increased current does not achieve increased output power in a fairly linear relationship, you have reached the "knee" and should run it below that amount of current, I have asked members if there is a rule of thumb how much percentage to reduce the current below the knee, for most diodes, to have a reasonable amount of run time life, but no answer yet.
 

405nanoMatt

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First I have heard of the 1.6 watt green, is that the raw output before the collimation lens? Where can I find them listed for sale? Curious what
Shmackitup said he has a few, I didn't ask about the can........yea the GBall can in the taebao ad didn't add up too me either, like the 08 vs. 0A N-company would change the part number if they put a different can on the same chip or changed the security block to that backing plate, data sheet should depict a block or backing plate if ndg7d75 was a gball, also ndg has always been a window can unit just like blue ndb, all the gballs are nugm/nubm but there could ever be a surprise, but the image is a window can so........if this is a revised stronger window 525 then there may be a less expensive GBall sister as well.
 

405nanoMatt

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I believe I have one of these gball 1.6 w diodes I have it ina streamlight protac 90 with an 800 mah 14500 and it easily sets leaves on fire and lights cigarette s in less than 6 seconds
 

Miya

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I heard it from my friend. The 525nm 1.6w diode is 2Watt!! At 2.5a current.
 

RA_pierce

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The spec. sheet says max 2.3 amps, but you know what we do, we run them higher.

Testing to find where the knee is at is just to find a fairly safe place to operate it at, you don't want to set the current on the diode where increasing it no longer produces a linear smooth increase of output, keep it below that by some healthy percentage. Anyone have a rule of thumb for that?

The rule of thumb is to use the manufacturer's current ratings.
Based on my analysis of the data compiled from many different laser diodes and laser diode types, the laser diode manufacturers' spec sheets rate a diode for the current that produces maximum efficiency in terms of energy in and energy out.
Here, it's common for us to use a simplistic and incomplete view of "efficiency" that only takes into account current in and light out, excepting the waste heat.

As we know, heat contributes to variations in power output of the laser diode, among other things, so it's important to take that into account.
The power curves we are used to seeing don't actually reflect the true performance of the laser diode.
I posted a detailed thread about this but the images have expired, apparently, so I'll attach one here:

The gist of it is that you can drive a diode as hard as you want, but you will obtain the best performance at or near the rated output power and drive current. Where the slope becomes negative, when actual efficiency is measured, is where heat generation increases relative to total output power. The "knee" of a current vs. output power plot does not accurately reflect this. Here is the main plot:


Note that the "knee" in the curves I have drawn correspond very closely with the rated output power for each diode tested.
The manufacturer ratings are based on EMPIRICAL results that demonstrate optimal performance for a series of laser diodes.
Of course, I'm not telling anyone how to drive their diodes but, for my lasers, I will opt for drive currents that result in the best performance and longest life rather than maximum power at the cost of premature failure or low duty cycle.
 

Alaskan

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Thank you, good information, fills some gaps in my understanding. From now on, I will likely run my diodes at rated output. For the green NDG7475 green laser diode, we often push them 35% or more beyond rated output, that amount of increase isn't such a great change in brightness to the eye, but burning, may make a difference to some.
 




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