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Laser Diode driving

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Dr_Doggy

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I got 2 laser diodes here both rated @ 300mW, now one says 2v, i don't know about the other(blu ray), but i have my driver circuit using the LM317 , but on the output I am reading 7v, and i can adjust the current to 42mA to drive the blu ray,

Now what about the 2v(IR) laser diode, can I use the same driver for it?

.....Here is schematic, I don't have C1 included, and my supply is a 9v

What modifications to this could i make to make it suitable for the IR?


...Now i think i know most of the theory... but doing a test run on the IR diode I had it running at 7V and turned it up to 500mA when i started getting some good light(IR), and the Diode isn't getting hot really, so whats wrong here? Maybe i shouldn't be trusting E-bay vendor data sheets?
 
Only learned a little about lasers, but the 300mW sounds like the light output, not power consumption. 7 volts sounds kind of high for a laser diode. Your schematic isn't showing up.
 
ohya schematic
 

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Laser diodes are EXTREMELY delicate and need a special active feed-back fold-back current driver circuit. Here is a discussion of driving requirements. Chances are that your circuit has already blown them.
 
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um, all i know is i'm using my phone cam to see it, and i just accidentally left it running for 30min, after that it warmed up slightly(40*c ish) but still lights up great, IDK about feedback control, all i know is that the diode hooks up to ground and current controller schematic an that s it,

btw how much power do i need for it to light up a match?
 
More than you can get from a laser diode that works with such a simple current controller, the diode you have is probably a module with a built in feedback controller, I doubt it will actually put out 300mw.
You need to be EXTREMELY careful when experimenting like this, you'll get spots from common laser diodes, but even a single chance reflection at close range from something that can put out 300mw can permanently blind you. Lasers are not toys.

If you're getting a good bright laser beam out of the circuit you're describing it is a module, and it is probably only 5-10mw
 
I have 3 watt argon LASER and a 1 watt krypton LASER, the krypton one lights matches no problem. The only catch is that they require a 240V 60A plug and water cooling of the LASER tubes. The laser heads are about 1.5m long and weigh >35 kilograms the power supply has been converted from 3 phase to single phase to run it in my house. Just happy to meet another LASER enthusiast. :)
 

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lol well they are definitely not like that, the blu-ray can burn things but I need to be right on the focal point, problem with my blu-ray is that it only likes burning dark things!

someday soon ima get started on a DIY N2 and CO2 laser,

CO2 to cut things such as glass test tubes and maybe other engraving

the N2 laser beam i once heard causes a form of ionization in air(N2) that makes the nitrogen a better conductor, the guy i read it from wanted to discharge a lightning bolt with it, im not going that crazy, but i do have a few ideas for a nifty little tazer or maybe something like a jedi sword
 
These LASERs work similar to N2 and Co2 LASERs by gas ionization. The tubes have leaked in atmosphere and need to be emptied and filled with clean argon and krypton gas. I have a good vacuum pump that can bring the pressure down to 5 millitorr the tubes need to be filled with clean gas at 120 millitorr for proper operation. I will have that sorted out soon and I will post some pictures and video on the forum.

Here are some more pictures ;)
 

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120 milli torr eh? is that for co2 too? What size pump can do that? Is that the same as CFM, What is that in microns?

I want to get a pump too, but i fear getting one too small, what should i look for ?

here is the bluray!
 

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240V at 60amps? That's 14.4kwwatts of power, for a 1 watt laser? The laser is .00007% effcient? A quick sanity check say something's wrong with the math there, are they really that inefficient?
 
Thats what the guy who gave me the LASERs told me. He has done measurments of the input current and it is 60 amps RMS. I know that it is inefficent, but gas LASERs are pretty inefficent.

The pump that I have is an Edwards 5, 2 stage vacuum pump, it can pull the tube down to 5 millitorr.

There are two tubes, one uses krypton gas and the other uses argon gas.

1 Torr = 1 mm Hg
1 Millitorr = 1 micron Hg

<Edit>
I will clean off the bench and I will take some pictures of the LASER heads and include them in my next post.
</Edit>
 
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Actually I messed up my math, it's .007% efficient, did a little more research, apparently this is not unheard of especially for a second hand laser. I had no clue lasers were that inefficient, no wonder we don't have multi megawatt lasers! Unless you've had it calibrated I'm going to guess you're not actually getting a full 1 watt of power out of it but that's still a goodly amount. I enjoy lasers myself, but with efficiency ratings like that I'd avoid them on general principals. Even audio is a couple percent efficient.
 
Actually there is no significant leak, the tubes have been sitting idle for >5 years so the vacuum will eventually draw in atmosphere through the smallest of microscopic holes. I am working on the argon tube now, I am connecting the vacuum pump through the gas manifold and pulling a deep vacuum inside the tube.

<Edit>
Sorry if I am stealing your thread from you, I really should start another one for my project.
</Edit>
 
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hello i'm just starting to learn about laser. i want to make a laser burner from dvd rw drive but i seem can't make the beam of the laser diode focus with my lens housing. what lens housing (in mm) should i use?
 
Here are the pictures!

I was connecting the filament to a high current transformer that put out about 3.5V to heat the tube and outgas the filament. I also have some pictures of the LASER power supply and LASER head. I now have the tube sitting at about 10 millitorr (10 microns). I will fill the tubes with gas tomorrow and post some pictures of this beast running.
 

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