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Hap

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Hi, Alex. Nice to see you posting. I'm sure you are out of class until sometime in January. Do you plan on attending classes in the summer?
Not quite sure paul. Yes, I am on break until mid January :)

-Alex
 

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@GSS
thanks for the tip about the better beam profile diode. I will try out your suggestion for the 450nm diode since I have plenty of A140 and M140 diodes I got for cheap. I was not specific in my comment but I was implying that I wanted to build a laser between 488nm-515nm somewhere in the cyan to mint green range

@paul1598419
Where would I get that driver? So far I've only used the drivers found on ebay that have an output voltage of 8v and "30-250mw" rating using only 3.5-5v input an it has worked for me without issues. Are there any cons that I am not aware of with these drivers?
 

paul1598419

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@GSS
thanks for the tip about the better beam profile diode. I will try out your suggestion for the 450nm diode since I have plenty of A140 and M140 diodes I got for cheap. I was not specific in my comment but I was implying that I wanted to build a laser between 488nm-515nm somewhere in the cyan to mint green range

@paul1598419
Where would I get that driver? So far I've only used the drivers found on ebay that have an output voltage of 8v and "30-250mw" rating using only 3.5-5v input an it has worked for me without issues. Are there any cons that I am not aware of with these drivers?
I don't know which driver you are asking about here. Do you have a link to it? A driver that can output a Vf of 8 volts from a 3.5 to 5 volt source is a boost driver, but if it is a Chinese driver, I would be very careful as many of these don't regulate current very well and that is far more important than the Vf voltage it puts out. I generally don't pay any attention to the listings claim of power it will produce because it is the current it can supply and regulate that is more important than any claims of power. If you would like to have a link to a driver that can be used with a specific laser diode, give me the diode you are planning on using and the power you would like to get out of it. I will then see what I can find for you.
 
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I don't know which driver you are asking about here. Do you have a link to it? A driver that can output a Vf of 8 volts from a 3.5 to 5 volt source is a boost driver, but if it is a Chinese driver, I would be very careful as many of these don't regulate current very well and that is far more important than the Vf voltage it puts out. I generally don't pay any attention to the listings claim of power it will produce because it is the current it can supply and regulate that is more important than any claims of power. If you would like to have a link to a driver that can be used with a specific laser diode, give me the diode you are planning on using and the power you would like to get out of it. I will then see what I can find for you.
This would be driver number 1 https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/112435751458

This is driver number 2
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/113167178610

I have used a 405-450nm driver to power up a 505nm diode by accident and it worked however I did not run it for very long once I realized it was the wrong diode and I do test the drivers with leds and a multimeter since I have yet to make a dummy load and have not killed a diode in this stage of testing, only when pushing the driver to max with just the 12mm module is when I have killed my diodes. I am on the process of getting the parts to make the dummy load 😅
 
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paul1598419

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That first driver you linked to is a very cheap driver that I haven't tried to use for several years. IIRC, it doesn't regulate current well at all. The second driver I am not familiar with. One thing you can do with a dummy load is to check how well a driver regulates current. You simply increase and decrease the number of diodes in your string and see if the voltage drop across your sense resistor remains the same.

You can get 50 10 amp rectifiers on eBay for ~$5.00. These work pretty well with a 5 watt 1% 1 ohm resistor to make a dummy load that is good up to 3 amps. For higher currents than 3 amps, I use heat sinked 20 amp rectifiers with a 0.1 ohm 1% resistor at 3 watts. Keep your connections short and only use heavy gauge copper stranded wire.
 
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That first driver you linked to is a very cheap driver that I haven't tried to use for several years. IIRC, it doesn't regulate current well at all. The second driver I am not familiar with. One thing you can do with a dummy load is to check how well a driver regulates current. You simply increase and decrease the number of diodes in your string and see if the voltage drop across your sense resistor remains the same.

You can get 50 10 amp rectifiers on eBay for ~$5.00. These work pretty well with a 5 watt 1% 1 ohm resistor to make a dummy load that is good up to 3 amps. For higher currents than 3 amps, I use heat sinked 20 amp rectifiers with a 0.1 ohm 1% resistor at 3 watts. Keep your connections short and only use heavy gauge copper stranded wire.
OK thank you I'll order the parts right now and I'll stop using the cheap driver. Although I do use much higher rated diodes for it. I was using that driver for some A140 diodes and they are still going without issues. It was more like a testing stage to see how to assemble and how it would fit in a host. I'm planning on getting my hands on some good drivers that can fit on the tool AAA to make the "swappable diode modules" in different wavelengths
 

paul1598419

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An A140 diode would not likely die with even a poorly regulated driver meant for nothing higher than 250 mW. The A140 is capable of being driven at 1.5 amps, which that driver would never get near. There are some very good drivers available that regulate current very well. You might try to familiarize yourself with the drivers offered on DTR's site. That way if you see them again, you will already know what currents and voltage they can supply.
 
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An A140 diode would not likely die with even a poorly regulated driver meant for nothing higher than 250 mW. The A140 is capable of being driven at 1.5 amps, which that driver would never get near. There are some very good drivers available that regulate current very well. You might try to familiarize yourself with the drivers offered on DTR's site. That way if you see them again, you will already know what currents and voltage they can supply.
Yeah that was the reason why I was using that driver, to minimize going over maximum current for the diode and I wanted to test fitting it in different hosts including the tool AAA and not risk an expensive diode also I came to know that the a140 and m140 are pretty rugged diodes. I event tried to kill one on purpose by handing it bare hand without static protection and long exposure to soldering heat and it works without issues.

Also thanks for the tip I'll look around DTRs website for drivers. I might even try to make one myself if it's not too difficult..
 

paul1598419

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That reminds me of five MS Envy hosts I used to build some brand new, not harvested M140 diodes for a guy who wanted them several years ago. All of them did over 2100 mW and he actually had one in his jacket pocket that got turned on and ran until the batteries discharged. Burnt a large hole in his jacket pocket, but the laser was still good even after all that. I used a 1.8 amp X-Drive to drive them which will shut down if it gets too hot. It is likely that the laser shut down several times during the time it was on. Once they cool down they will start back up again. Just a true story I thought you might like to hear.
 
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That reminds me of five MS Envy hosts I used to build some brand new, not harvested M140 diodes for a guy who wanted them several years ago. All of them did over 2100 mW and he actually had one in his jacket pocket that got turned on and ran until the batteries discharged. Burnt a large hole in his jacket pocket, but the laser was still good even after all that. I used a 1.8 amp X-Drive to drive them which will shut down if it gets too hot. It is likely that the laser shut down several times during the time it was on. Once they cool down they will start back up again. Just a true story I thought you might like to hear.
Way to save the day with the thermal shut down Paul, I don't like to think about what would have happened, had the laser not shut off and would have kept burning a hole longer also overheating the batteries and very likely would have thermal runaway and most likely no more laser but still just goes to show how robust those diodes are. Thank for sharing, I'll keep that in mind while carrying a laser in my pocket
 




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