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Lpc826 not bright help

Shiraiei

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I just recently bought 2 lpc826 diode and placed them in a housing and when I tried hooking it up to my lm317 driver set at 500+ ma , and it just produces this small red dot and I don't think it's supposed to be this weak.would be great if anyone could help.63604
 

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hakzaw1

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Just how did you set the current?? IF you used your red diode-- that was a mistake--a 'dummy' load must be used and never the laser diode.
 

Shiraiei

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Just how did you set the current?? IF you used your red diode-- that was a mistake--a 'dummy' load must be used and never the laser diode.
I thought I could get the current I want with the value of the resistor?
 

diachi

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I thought I could get the current I want with the value of the resistor?
You can calculate it, yes, but it's best to test the driver with a test load before connecting your laser diode. Also, never run the driver without a load, if you do make sure to discharge any capacitors on the output before connecting a diode.
 

Shiraiei

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You can calculate it, yes, but it's best to test the driver with a test load before connecting your laser diode. Also, never run the driver without a load, if you do make sure to discharge any capacitors on the output before connecting a diode.
So other than not discharging to capacitor what could I be doing wrong here? I can't seem to know why it is not working correctly
 

Anthony P

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I am no expert, but I don't think the 9v battery is adequate... not enough input current available.
 

Shiraiei

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I am no expert, but I don't think the 9v battery is adequate... not enough input current available.
I don't think so I tried hooking it to my 12 v power supply and surprisingly it is dimmer than when I was using the 9 volt
 

Alaskan

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A 9 volt battery, the type used in radios etc., is capable of several amps of short circuit current for a period of time, up to 5-10 amps, some higher, I read a report of up to 20 amps if new, depending upon the type. Not long, but it will. There is more than enough current capacity for that diode with a 9V battery, way more than enough. You may have "LED" destroyed that laser diode, now it's probably just an LED, a low power one.
 
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Shiraiei

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A 9 volt battery, the type used in radios etc., is capable of several amps of current for a period of time, up to 10 to 20 amps if new, for some of them. Not long, but it will. There is more than enough current capacity for that diode, way more than enough.
Yea but do you think I might have damaged the diodes because I used a 2.4 ohms resistor which the current output is around 500mA maybe that's too much for the laser diodes?
 

Alaskan

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The resistor isn't a good idea, as the laser diode warms, it will usually pull more and more current until it dies, with just a resistor. Did you heat sink it?

 

Shiraiei

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The resistor isn't a good idea, as the laser diode warms, it will usually pull more and more current until it dies, with just a resistor.
So what tips can you give me , I'm going to try again with new diodes
 

Alaskan

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Get a laser diode driver, or build one.


Search this forum for "LPC-826"

I recommend the LPC 836, it's a bit more output, or the LPC-840, even more: https://www.ebay.com/itm/5x-Mitsubishi-LPC-840-650nm-400mW-500mW-Red-Laser-Diode-TO18-5-6mm/113220774194
 

Shiraiei

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Get a laser diode driver, or build one.


Search this forum for "LPC-826"

I recommend the LPC 836, it's a bit more output, or the LPC-840, even more: https://www.ebay.com/itm/5x-Mitsubishi-LPC-840-650nm-400mW-500mW-Red-Laser-Diode-TO18-5-6mm/113220774194
i cant seem to find any can you please let me have the link thanks
 

Alaskan

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You can google the forum here, or google the world to find what you need. Maybe another member will help.
 

diachi

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i mean the diy laser driver for lpc 826
The LM317 + resistor in current limit mode is a driver... Which should work, providing you use a test load to check it before hooking up the diode. Always keep ESD in mind too, diodes are very sensitive to static shocks.
 




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