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That oddball diode. (one off wavelengths)

photonaholic

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Ok, so recently I scored 5 diodes, all identical 505nm (harvested, so I don't know the manufacture) , they were all in 12mm hosts and all have identical drivers. all diodes are operating at 5.5 volts 90-95Ma draw each. but one diode lases very bluish green. the other 4 diodes lase identical frosty green, but this one is a keeper. is it common for an odd diode in a batch to produce a couple of NM off from others (to the point of noticeably visible difference) ??? here is a photo, does not do justice to what the eye sees... The comparison shots may seem unfair, I replaced the cheap plastic lens in the one off to glass. I have an order of more glass lenses due from China soon.... (I also included a photo of the commercial A/C driver. the diodes came from Christmas decorations)


IMG_1436.jpg
 

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paul1598419

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These are Sharp diodes. I have tested many new Sharp diodes for wavelength over the past year plus and the so called 505nm diodes can end up anywhere from 502nm to 510nm, depending on the iteration. I have four spectrometers, but my best is an Ocean Optics USB2000+ that measures between 340nm and 850nm. It is accurate to 0.25nm. It is likely most of your diodes are on the high side except for that one that may be as low as 502nm.


If you can look at the diode's window, you should be able to find a number micro-printed around the window that starts with an SB. If you can give me that number, I can tell you where these ended up from the low side to high.
 

photonaholic

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These are Sharp diodes. I have tested many new Sharp diodes for wavelength over the past year plus and the so called 505nm diodes can end up anywhere from 502nm to 510nm, depending on the iteration. I have four spectrometers, but my best is an Ocean Optics USB2000+ that measures between 340nm and 850nm. It is accurate to 0.25nm. It is likely most of your diodes are on the high side except for that one that may be as low as 502nm.


If you can look at the diode's window, you should be able to find a number micro-printed around the window that starts with an SB. If you can give me that number, I can tell you where these ended up from the low side to high.

I will see if my macro setting on my camera will do it. I'm an old guy, I am proud of myself every time I solder wires within a mm of each other and not do a sloppy job. (my eyes ain't what they used to be) :p
 

paul1598419

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I will see if my macro setting on my camera will do it. I'm an old guy, I am proud of myself every time I solder wires within a mm of each other and not do a sloppy job. (my eyes ain't what they used to be) :p

I'm no youngster either. I saw my 60th birthday several years ago. I use a loupe to see the number, but you can likely use the macro setting on a good digital camera too. I have been soldering my entire adult life, so I can still make a good solder joint. I have two thermostatically controlled solder stations. My best is a rework station that can be set to any temperature up to 500* C.
 

Benm

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Well yeah, it can happen that a production run results in some diodes of somewhat different wavelength diodes.

The question is what happens to them: The factory may see them as out of spec, rejects, and scrap them for recycling... or they somehow make it onto the market where they'll sometimes be worth premium price.

Usually companies make these diodes in large batches, and everything that doesn't meet spec (power curve or wavelength) is just rejected. Then again not all employees are idiots either, and they just bring the off-wavelength diodes to market since they are worth so much worth compared to scrap materials.

On the other side you have batches of reject diodes that are sold on aliexpress or ebay for a discounted price, and finding one that's been rejected due to wrong wavelength instead of low performance is a matter of luck.
 

photonaholic

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I'm no youngster either. I saw my 60th birthday several years ago. I use a loupe to see the number, but you can likely use the macro setting on a good digital camera too. I have been soldering my entire adult life, so I can still make a good solder joint. I have two thermostatically controlled solder stations. My best is a rework station that can be set to any temperature up to 500* C.
Grandpa taught me to solder back in the 70's when we built a crystal radio together. :) Got really lucky many years ago and scored enough real (lead) solder to keep me soldering for the rest of my life. (surplus buy) I still have my 400 watt pistol and use it for big things like large power lugs and tinning 14 gauge wire. all the way down to the little 15 watt for tiny ICs.
 

photonaholic

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Well yeah, it can happen that a production run results in some diodes of somewhat different wavelength diodes.

The question is what happens to them: The factory may see them as out of spec, rejects, and scrap them for recycling... or they somehow make it onto the market where they'll sometimes be worth premium price.

Usually companies make these diodes in large batches, and everything that doesn't meet spec (power curve or wavelength) is just rejected. Then again not all employees are idiots either, and they just bring the off-wavelength diodes to market since they are worth so much worth compared to scrap materials.

On the other side you have batches of reject diodes that are sold on aliexpress or ebay for a discounted price, and finding one that's been rejected due to wrong wavelength instead of low performance is a matter of luck.
I actually got a bulk deal on Christmas decoration projectors. The deal worked out to exactly 6 dollars per 12mm module after gutting the decorations. The red diodes are all 638nm and really bright too. Oh I forgot, add $3 each for the glass collumation lenses I installed to replace the single element plastic ones. :)
 

paul1598419

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The 70s were my college years. I built a crystal radio too back in the early 60s. But, I did mine by myself. Used a quartz crystal and a wire to make the demodulator diode. Then wrapped some thin copper wire around a large dowel to have an inductor with a piece of aluminum to act as a wiper to change the inductance and tune the radio.
 

hakzaw1

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See my reply at the other section where you asked the same thing..AND jacking another's thread can be seen as rude.___________

+++++++++@OP Wayne.. are these the green lasers on a stake==for outdoors?
I thought both or your R and G came from same light.. good find and TY for the 'share'.. me want ;-)
 

paul1598419

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I need this can anyone help, my son and his friends , well they did to much let's just say

As I told you in another thread, this is a BB8M driver. The Black Bucks come from X-Woosee in Russia and can be found on eBay. The 8m can be set for current up to 8 amps. That is much more than you will need, but it also has other features that allow one to add a 10 K pot to adjust power on the fly and a thermistor that will shut your laser off if your diode gets too hot.
 

photonaholic

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The 70s were my college years. I built a crystal radio too back in the early 60s. But, I did mine by myself. Used a quartz crystal and a wire to make the demodulator diode. Then wrapped some thin copper wire around a large dowel to have an inductor with a piece of aluminum to act as a wiper to change the inductance and tune the radio.
I was too little in the 60's. Remember those 101 project sets from Radio shack with the springs and a little book of projects? or the "Engineers Notebooks" Forrest Mimms published?? Mine are all yellow and beat up, but somehow managed to survive.
 

paul1598419

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I was never a fan of Radio Shack, so I don't have anything they ever sold. By the 70s I was working full time as a TV technician while going to school. I was able to get parts for anything through my work place. But, since I moved around a lot in my adult life, many of my books didn't survive all the moves.
 




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