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488nm Diode Driver Questions

94Z28

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Hello everyone! Been a long time since I've built a laser or been around. I have mostly been building flashlights.

Anyway I noticed the 488s have come down in price and decided to build one. The issue is a driver, and what current I can run. Will the 220mA from Survival work? What's the max current for these 488? I see DTRs testing, not sure what safe current is.
 



paul1598419

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Hello everyone! Been a long time since I've built a laser or been around. I have mostly been building flashlights.

Anyway I noticed the 488s have come down in price and decided to build one. The issue is a driver, and what current I can run. Will the 220mA from Survival work? What's the max current for these 488? I see DTRs testing, not sure what safe current is.

I have tested many of the Sharp diodes for wavelength, power output and drift, The part number for these is GH04850B2G and they tend to come in at anywhere between 486nm and 493nm. I have built several and have set the current to 275 mA on most, but you can go as high as 300 mA as long as they are well heat sunk. They will drift much more with heat than with current. So, the Driver you specify from Survival should work fine. Hope this helps.
 

94Z28

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I have tested many of the Sharp diodes for wavelength, power output and drift, The part number for these is GH04850B2G and they tend to come in at anywhere between 486nm and 493nm. I have built several and have set the current to 275 mA on most, but you can go as high as 300 mA as long as they are well heat sunk. They will drift much more with heat than with current. So, the Driver you specify from Survival should work fine. Hope this helps.
Hello Paul,

Long time no chat and thanks for the heads up. I appreciate the tip for 300mA. How much shift do you see here? I've always wanted to experience a "baby blue" beam.

I have to rebuild my 520 soon also.. the adjustable blackbuck 8m in a maglite died somehow. I was able to dial it up or down with a hole we drilled and placed a pot in it. Dropped one time and diode never relit.
 

Lifetime17

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Hi ,
400 t0 430mA is a good spot for these diodes that would bring the WL up to about 490nm. Lower mA's from 55mA /100ma will keep the WL closer to 488nm . I set my drivers for the 488 diode around 100 to 125mA tops .
Rich:)
 

paul1598419

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Any time. If you have specific questions about any of these Sharp diodes PM me. I have tested most of the ones that came out in the past two years and have specs on each. Good luck on your build.
 

Lifetime17

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Hi 94Z28,
Here are the tested driver settings for the 488nm diode from DTR site..
These might be individual diodes being tested , I think they were tested by Paul I dont remember maybe he will verify the results.
Wavelength Tests
Diode #1 486.8nm at 55 mA
Diode #2 487.4nm at 70 mA
Diode #3 487.2nm at 55 mA
Diode #4 488.3nm at 130 mA
Diode #5 490.3nm at 120 mA
Diode #6 491.8nm at 100 mA
Diode #7 490.7nm at 80 mA
Diode #8 487.6nm at 110 mA
Diode #9 486.9nm at 100 mA
Diode #10 490.0nm at 95 mA
Diode #11 490.2nm at 100 mA
Rich:)
 

ZRaffleticket

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Yup those are Paul's tests for my first batch of these. I still have a few of them, though all on the greener side >488nm.
 

paul1598419

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Hello Paul,

Long time no chat and thanks for the heads up. I appreciate the tip for 300mA. How much shift do you see here? I've always wanted to experience a "baby blue" beam.

I have to rebuild my 520 soon also.. the adjustable blackbuck 8m in a maglite died somehow. I was able to dial it up or down with a hole we drilled and placed a pot in it. Dropped one time and diode never relit.
The lower the wavelength of this diode the more light blue it appears. I built one for my daughter that was 486nm and it was her favorite color. I have one in my collection that is exactly 488nm. These will shift up in wavelength if not heat sunk properly. That makes them look more green.
 

RedCowboy

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Actually frequency is described as higher or lower while wavelength is denoted as longer or shorter because wavelength is the distance between wave crests so the correct way to say it would be the shorter the wavelength the higher the frequency or the more blue looking the beam in this case.
 

paul1598419

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The wavelength, or period, is just the reciprocal of the frequency.
 

RedCowboy

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Wavelength denoted by a numeric value in nanometers ( 1 billionth of a meter ) is a measure of distance, it's not higher or lower, wavelength is longer or shorter.
 
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paul1598419

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No, you simply don't understand the relationship between a wave period and its frequency. They are inversely proportional to each other, so using words like a wavelength is greater is the opposite of its frequency. It you don't understand this I can see why you would want to use only words like "longer and shorter" to help you keep yourself from becoming confused. To say that my use of a greater wavelength is not inherently wrong. Just because it is a distance, like miles are, you can say that it is greater or lesser.
 
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RedCowboy

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You didn't say greater or lesser you said lower wavelength, that's incorrect, nowhere in anything technical have I seen anyone wright about " lower wavelength " it's longer or shorter.
People do say lower or higher frequency as there is a measure of cycles per unit of time, but there is no unit of time factor in the measure of wavelength which is distance.

A lower numeric value in wavelength ( nanometers ) equals a higher frequency.
 

paul1598419

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Lesser or lower, it's all semantics. The wavelength of an UV laser is lower than the wavelength of a IR laser. That is not inherently wrong. Sorry if you disagree.
 

RedCowboy

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You're wrong, wavelength is longer or shorter, frequency is higher or lower and the frequency of a UV laser is higher than an IR laser, not lower.
 

paul1598419

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Yes, the frequency of a UV laser IS higher than an IR one, but we don't describe lasers in terms of their frequency. We describe them in terms if their wavelength......which is lower, lesser or shorter. It is more precise to describe wavelength as shorter or longer, but it is not incorrect to use other terms either. You are nit picking and it is not worth my time to argue this any longer.
 




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