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ArcticMyst Security by Avery

Diode Virgin Makes Blue Light...But Problems

Joined
Dec 27, 2008
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Harvested a 5 pin blue from burner. Built a LM317 ckt published here. Got my parts at radio snack. They had no 1 ohm or 4 ohm resisters so i cant measure current. They had no 100 ohm tweakers, best i could find was a 10 k on series with a 10 ohm on output of 317. Looks bright enough when focused with a aixiz PL. When i adjust pot it does drop out, go the other way it turns on keep turning it dosnt get brighter. Diode looks good focused well at 30 ft. How much current am i running rughly how can i measure it, is 10k pot restricting flow...sorry i know NOTHING about electronics.

PS- I need to change my name from diode virgin now ;D

In case any of you follow PL i am laserman532 and on alt. lasers i am Pat B. I think i want to re name myself on this forum to laserman532 if anyone knows how to do that, or do I just make another account?
 





D

Dr.LaSeR

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Joined
Mar 8, 2008
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with a 10ohm resistor, assuming your pot has zero resistance when it's set to the least resistance, you will be running 125mA.

With the LM317 it's very easy to figure out your current. Just use Ohm's law.

Voltage (in this case it's always 1.25, because that is the ref voltage of the lm317) divided by resistance (10ohm's, because we're assuming your pot has 0 resistance when it's cranked all the way up, and you said you also used a 10ohm resistor) = current (125mA in this case)
 
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With all due respect gooeygus...you might as well be speaking vulcan- but it all sounds very technical ;D
 

Raybo

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Oct 30, 2008
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V = I x R (Voltage = Current multiplied by Resistance)

R = V / I (Resistance = Voltage divided by Current)

I = V / R (Current = Voltage Divided by Resistance)
 
Joined
Dec 27, 2008
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Ok sounds good so what do you do?

I assume measure voltage across diode

and current in series with the diode (with meter set to ma)

Dot know why I want resistance - But if I knew the resistance I could calculate one of the others if I had one of the others

If you guys give me links i will study hard, i promise. I just do better work if i can communicate on a phone because to navigate this website.....well frankly im too old ;D
 
Joined
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The voltage you will use in the equation when using the LM317 circuit will always be 1.25V, because this is the reference voltage for the LM317 regulator.

SO it's always going to be 1.25 / resistance = current :cool: :cool:
 
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Well thanks to gooeygus taught me how to measure current.. I got my other 80t running on the lm317 ckt and adjusted current to be 97ma it has been running out my window hitting some trees for about an hour now in my new ATM-20 (aixiz table mount clam shell heatsink) shameless plug :D

Tonight is central oregon is very foggy, very cold and whorefrost on the trees and now a huge shaft of purple light piercing the night :eek:


I found out that my 10 k pot allows me to turn it on and off however not a fine enough control on current. So today I ordered everything i need from mousers and when I get my LOC diodes from andrew I should be good to go.
 
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awesome! 405nm on a foggy night is really cool to see piercing into the night sky. It sure would be cooler if it were a few watts though ;D

If you need any more help with anything dont hesitate to call again.

I'm sure I'll be getting a hold of you very soon as Jon now has those lasers in his possession. the 2020 (doorstop ;D) is totally out of gas, one of the 164's is also out of gas but the tube is still in good shape but the other 164 looks to be in perfect condition (according to Jon, i'll have pictures on monday) and is still gas intact. Also he said the 265 is even better than he remembers. The pass bank and other components look perfect, and he said the paint and front face still look glossy and new. So hopefully I'll get at least one working head and PSU out of the deal :cool:

You're going to be my go-to-guy when I decide to muster up to courage to swap the plasma tube into the 165 frame :eek: :eek:
 




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