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Just joined ! Need a few tips

EzPk

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I've been reading on this site for a while now as I am building my first laser. And have decided to join in an attempt to learn more about general electronics and lasers. I have some experience with electronics and through reading these forums and asking the all knowing oracle (Google) I've managed to get an idea of what it is I need.

(I would appreciate any input on my choices good or bad and why or why not)
I purchased the following items so far:
This flashlight as the host.
6x SF-AW210 diode in an Aixiz module.
3x Energizer Li-Ion CR123's
rkcstr driver.
(I also plan on purchasing a good heatsink once i get the dimensions of the host)

After a lot of digging around this site and searching Google I've decided a safe current for the diode would be 180mA. So it would be powerful enough to burn but still have decent life.(right?)
The thing I'm having trouble with is calculating the power(mW) output of what this is going to be. I'll have 9V from the 3x CR123's in series at 180mA current. So by Ohms law P=E x I or
9 x .18 = 1.62 . This is where I don't understand. 1.62 Watts ? So .00162mW ? This doesn't seem right. Ideally I would want ~200mW output power. Correct?
Basically my question is, what am I missing?
 
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JLSE

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What are you missing? Not much, 180mA is a nice current for a 6x, but calculating the output is not likely to happen.

A guess can be made if you have other lasers of known power, but short of a laser power meter, there is no easy way to tell. It would be safe to say you will get between 150mW to just over 200mW, it really depends on the diode and also lens.

There is a member here who sells a nice power meter which is thermopile based and quite accurate.

Start here >http://laserpointerforums.com/f64/fs-laserbee-i-data-logging-215-99-shipped-43922.html
 

EzPk

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Ohhh I see what you're saying. And thanks for the link !
I'll definitely have to look into getting one.

Another question though, by having 9V ill need 50 ohms of resistance for the 180mA current. I set the pot on the rkcstr driver to 20 ohms and have purchased some 30 ohm resistors. so by going from the battery to a switch and from the switch to the 30 ohm resistor and resistor to the driver that would be 50 ohms would it not?
 

JLSE

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I dont want to answer that one, as I havent used that driver, but many here have. I will let someone else take that one ;)

Do you have to use resistors with that driver? I thought it was a straight hook up?
 

EzPk

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well yes and no i guess. yes it has a pot already on there but the max i could put it to was about 23 ohms. and if i need a ~4.8V operating power for the diode itself and another ~2V for the driver thats already ~7V and adding another 2V for longer life(? considering the batteries loose voltage and current over time?) gives 9V so ill need another 30 ohm resistance otherwise my current would fry the diode instantly.
 

JLSE

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Have you tried attaching a test load and testing the actual output first? That is where I would start and at least you can see the current.
 

EzPk

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No I have not. How would one go about performing one of these test loads :p
 

JLSE

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All the questions you may have will most likely turn up in a forum search, see post #7 here > http://laserpointerforums.com/f38/test-load-44348.html

Use 1N4001 diodes and a 1ohm resistor. Measure the voltage across the 1ohm resistor, set your DMM to 2000mv, 1mv = 1ma.

The 1N4001 diodes in series should measure 5-6v as the voltage across the load.
 
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So by Ohms law P=E x I or
9 x .18 = 1.62 . This is where I don't understand. 1.62 Watts ? So .00162mW ? This doesn't seem right. Ideally I would want ~200mW output power. Correct?
Basically my question is, what am I missing?

I don't know if you have cleared this up yet, but mW is miliwatts not megawatts. So then 1.62W would be 1620mW. The diode will pull about 4.8-5.2v at 160ma, but the power output of the diode would be somewhere around 200mW (just a guess)

I know I am also somewhat new, but I hope this helps!
 

EzPk

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Alright sounds good, thanks for all the help !
Guess I'll have to get a decent multimeter this POS I have isn't cutting it haha

Thanks again !
 

EzPk

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I don't know if you have cleared this up yet, but mW is miliwatts not megawatts. So then 1.62W would be 1620mW. The diode will pull about 4.8-5.2v at 160ma, but the power output of the diode would be somewhere around 200mW (just a guess)

I know I am also somewhat new, but I hope this helps!

Yes your absolutely right ! I went the wrong way in my calculations

curse my horrible math skills

X_X

Just a curious question for you. Have you built any functioning lasers yet, GaroBlu?
 
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No, but I am in the process. I have everything ordered so it should be done in a month. (Shipping from DX to USA, then to here)

Also, I do know a thing or 2 about the DIY tech stuff and to be honest answered a question anyone else could have. In fact you could have too with searches. Generally what you are going for will yield 200mW output. Just be sure to keep enough power flowing into the rckstr because you should always be running at least 2v more into the driver than what you require out of it.
 
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@ EzPk, Go to the LASER PRO SHOP SECTION of the Forum, & find the LASER TOOLS F/S ad by FLAMINPYRO. He is currently selling the (DUMMY LOAD) that you need to set the current on your driver. They are already built & are only $15.00 USD I think......rob
 
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I had the pleasure of meeting with EzPk yesterday at his place, he's a very cool guy, I hope everyone helps and welcomes him as it seems they are beginning to! Best Wishes! -Glenn
 




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