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Best Way to Add LED Indicator?

Meatball

Meatball

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Where, in the normal LM317 current limiter circuit, would be the best place to add an LED? I would like to add one to both my LOC driver and Blu ray driver. I don't know if the differing resistor values on these drivers would affect where the LED and resistor would be added. LEDs should simply indicate power on and off for each driver. Thank you much!
 





BuildAbluraylaser

BuildAbluraylaser

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Laser diode driver input, you can find leds for different voltages, if you have a 9V input, use 56 ohms, 1/2 watt, for 6v use 20ohms 1/2W. For 12v, look up different websites, led for that voltage are more currently available. For any other voltage, replace the resitance by a pot (100ohms) and lower resistance until led lights up nice. Connect it like that for the pot :
@ = connection
+ input of driver @ 1 pin of pot +2 pin of pot (connested togethere)
3 pin of pot @ LED positive
LED negative @ - input of driver
 
Darkarmyofone

Darkarmyofone

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maybe im totally one hundred percent wrong... but i've used a single led as a test load for my lm317... if your running plenty of power to your diode... would a 3.7volt 3mm blue led cause any problems if wired up to the OUTPUTS of the driver just like the diode so they light up at the same time? i mean if you know your outputs you could wire in a resistor to provide the LED with the minimum voltage required to run...

just a thought... but i've never attached two diodes to an output of a driver before... so dont try it until someone sheds a little more light on the situation.

Dark
 
BuildAbluraylaser

BuildAbluraylaser

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Ya your wrong lol.
The LED will porbably take most of the current available, leaving you with a dim laser diode. But It won't kill it.
 
lasersbee

lasersbee

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The best place is between the batteries and the driver right after the ON/OFF
switch..
Depending on the LED and battery voltage used a 20-50mA current to the LED
should be sufficient... A red LED will require a about a 100 Ohm 1/4 watt resistor
for a current draw of about 30mA on a 6volt supply...
The led might be bright enough with a 330ohm resistor drawing about 10mA...
You'll need to experiment....

Jerry
 
lasersbee

lasersbee

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I use 2pc 3mm ultra bright Blue LEDs mounted into the eyes of a small metal Skull
on my Harley as an Alarm Enabled Indicator... the two of them draw about 7ma
and flash once per second... they are so bright at that small current that you can
see the "eyes" from quite a distance away..

Jerry
 
FireMyLaser

FireMyLaser

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That's stupid. Why get an expensive pot when you can get the proper resistor, which is much smaller too?

Ohms law:
R = V / I

Or google LED calculator.
 
BuildAbluraylaser

BuildAbluraylaser

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Pots expensive?
lol, I get trimmers for .30$ a piece.
I didn't think they could be expensive...
He can just use this to find the proper resistance, and than replace those by resistors.
If they don't all use the same resistance, then you test each of those and note the resistance needed...
That's not stupid...
 
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FireMyLaser

FireMyLaser

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Like I said, 5-10mA is fine.

I've posted this like a gazillion times: red, orange, yellow-yellow/green LEDs are 2V, the others 3.3V.

If you're going to do something, do it right. The chances are that you'll over-do the pot and get screwed.
 
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BuildAbluraylaser

BuildAbluraylaser

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Turn the pot until le LED shines good, then stop imidiately, disconect the pot and LED without turning the nob, and test the resistance of the pot. That's what you need.
 
FireMyLaser

FireMyLaser

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rageff-1.png

What? I'm not mad... :p
 
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