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Revolution in diode cooling!

Things

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I have done this before to same poor little diode, and it still ran fine for this picture I took 10 minutes ago.

It's a LOC being direct driven from my bench PSU. I assure you, nothing has been added to protect the diode from the water. Even just direct tap water.



Who wants to decan some 445nm diodes and try this? :D

Cheers,
Dan
 

Benm

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Hmm.. it doesnt really surprise me that it works under water - there is little reason it shouldn't. You may see some electrolysis around the leads, especially when you would use a 445 or bluray because of their higher voltage. This will corrode wires eventually.

The chief problem is: what will happen when you take it out? If you let the diode dry, i suppose chances are there will be some (calcium, magnesium) salts from the tap water that dry up on the output face, ruining the beam.

Anyway, let it run over night, and see if it survives that. The most likely failure would be corrosion in the leads, which would not damage the diode, just open circuit the whole thing.
 

kiyoukan

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you could do that with mineral oil and not risk any damage...
Or at least distilled water. to me seems like a not needed risk.
Good luck and if you have fun then have fun!
 

Things

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The voltage is pretty low, any electrolysis is gonna be slow in pure tap water, until enough matter dissolved in it to make it conductive. Like I said before, this diode has been swimming before and it still works fine.

And yeah, thats why I was so confident in dumping it in water, nothing it can really do.

Cheers,
Dan
 

millirad

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Interesting experiment! You can de-ionize the water by boiling it first and then let it come to room temp. Then pour that into your container. ;-)

Edit: Boiling the water causes many of the bicarbonate ions to precipitate as calcium carbonate as it cools and then they fall to the bottom of your container. So carefully pour only the top of the water into your container. It isn't de-ionzed fully but it does significantly reduce the ions in-solution.
 
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Toke

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The boiling will remove dissolved oxygen and make water less corrosive.
Regular tap water is conductive and you use that to measure water levels in e.g. coffee machines.
It just happen that at low voltages it does not really matter.

Now how to implement this revolutionary discovery in a pointer? :D


Distilled or osmosis filtered water is incredibly corrosive and must be carried in either plastic or acid resistant steel pipes. On ships it is run through a calcium filter to give it some ions and make it less corrosive.
 

jander6442

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Nice, I like... When you remove it out of submersion you could spray that automotive electric cleaner to store it.
 

IsaacT

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As Kiyoukan stated, Mineral Oil works better. I think it would be possible to integrate it into a pointer as long as you had maybe a hollow copper heatsink that you could trap the fluid in....I don't know how much more effective it would be at heat dissipation but you could definitely try it.
 

Toke

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As Kiyoukan stated, Mineral Oil works better. I think it would be possible to integrate it into a pointer as long as you had maybe a hollow copper heatsink that you could trap the fluid in....I don't know how much more effective it would be at heat dissipation but you could definitely try it.
Oil is used in high voltage transformers, the kind you see atop power poles.
It serves both as an electric insulation that keep out moisture and as heatsinking medium.
(also used inside older really high voltage cables.)

I am afraid that it would be rather, well pointless, in a pointer.
The module does not have any complicated shape that could best be reached by fluid, and the heat capacity of oil is not impressive.
 

BShanahan14rulz

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I think he just did it because he can ;-)

I say freeze the whole thing solid and try again! Probably won't work since water expands so much when it freezes (water! whoa!) that it could shear the bond wires...

BTW, I don't think the bond wires would corrode if they're gold.

Anyways, neat!
 

IsaacT

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Oil is used in high voltage transformers, the kind you see atop power poles.
It serves both as an electric insulation that keep out moisture and as heatsinking medium.
(also used inside older really high voltage cables.)

I am afraid that it would be rather, well pointless, in a pointer.
The module does not have any complicated shape that could best be reached by fluid, and the heat capacity of oil is not impressive.
Thanks for that explanation. I was aware of Oil's supposed capabilities but was unaware as to its purpose and efficiency
 

kiyoukan

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the only good oil would do is inside the aixiz module.
It helps cool the window and the outer can that is not pressed up to the metal.
but if you do that you also have to make sure that the heat does not expand the oil a bit and crush the diodes window.
 

oic0

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Oil has crappy heat conductivity. Ive seen it used in PCs before, not near as good as youd think.

I would go with a pure alcohol.

Also, if one were using water, there are additives used for computer water cooling systems to reduce corrosion.
 




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