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Need help w/ choosing resistor for my Dorcy Jr.

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Can somebody please help me with this part. I received my new diode today (from Stone Tek) and I need to measure what resistor I should use for it. Do I need a 1/2 watt or 1 watt and so on... I also have a multi meter so im good to go. Do I turn the dial on the multi meter to the A ~ or which one is it? Also how exactly do I go about doing this. Do I just put the multi meter prongs on the - and + leads of the diode by itself or what because it seems as though if its under "load" which im assuming means hooked up to power then wouldnt it just kill the diode when you power it? Sorry for the stupid questions but I just want to be extremely careful with this 3rd diode since I cant afford to keep buying and burning these things up :'(. I would really appreciate the help with this part as this is the only step I need to complete my laser.

Thanks
 





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Re: Need help w/ choosing resistor for my Dorcy Jr

what are you connecting the resistor to?

you're not just connecting the diode directly to a battery through the resistor are you?
that would probably be why you're burning them out.

Anyways, you dial the multimeter to "[ch937]", or sometimes it will be labeled with a diagram of a resistor which looks like: --/\/\/\--
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

CharlieMurphi said:
Can somebody please help me with this part. I received my new diode today (from Stone Tek) and I need to measure what resistor I should use for it. Do I need a 1/2 watt or 1 watt and so on... I also have a multi meter so im good to go. Do I turn the dial on the multi meter to the A ~ or which one is it? Also how exactly do I go about doing this. Do I just put the multi meter prongs on the - and + leads of the diode by itself or what because it seems as though if its under "load" which im assuming means hooked up to power then wouldnt it just kill the diode when you power it? Sorry for the stupid questions but I just want to be extremely careful with this 3rd diode since I cant afford to keep buying and burning these things up  :'(. I would really appreciate the help with this part as this is the only step I need to complete my laser.

Thanks

Use a ~5 ohm 1 watt resistor, or twist & solder two 10 ohm resistors together in parallel to make a 5 ohm.

don't use a multimeter, it sounds like you'll just confuse yourself even more.

PS: If you keep burning up diodes, I offer [link=http://www.hightechdealz.com/index.php?main_page=product_info&cPath=3&products_id=8]a similar diode ~200mW 650nm[/link] for a little less than the stonetek diodes. I'll be having a July 4th sale tonight till July 5th on diodes as well.
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

Is it possible that I could get away with using a 1/2 watt 5.6 ohm resistor. I only have a 5.6 ohm resistor at the moment. Is there a huge difference between using 1 watt or 1/2 watt as far as resistors goes?

Thanks for the help
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

CharlieMurphi said:
Is it possible that I could get away with using a 1/2 watt 5.6 ohm resistor. I only have a 5.6 ohm resistor at the moment. Is there a huge difference between using 1 watt or 1/2 watt as far as resistors goes?

Thanks for the help
Yeah 1/2 watt 5.6 ohm will work great. You won't be putting more than 500mW through it so it will be fine.

good luck!
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

Ok so following the video tutorial that I just linked here, I used the 5.6ohm 1/2 watt resistor and the diode was extremely dim. Does that mean that the diode is shot or that I need a different resistor? It still lights up barely. This is the third time that this has happened. I just cant keep spending money left and right burning these things up. What am I doing wrong here! I followed the video tutorial above..EXACT..?
 

jake21

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Re: Need help w/ choosing resistor for my Dorcy Jr

yea its dead its not how u build it, things can happen like to much heat from ur soldering gun or u might of shocked it with ur hand ect...
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

CharlieMurphi said:
Ok so following the video tutorial that I just linked here, I used the 5.6ohm 1/2 watt resistor and the diode was extremely dim. Does that mean that the diode is shot or that I need a different resistor? It still lights up barely. This is the third time that this has happened. I just cant keep spending money left and right burning these things up. What am I doing wrong here! I followed the video tutorial above..EXACT..?
Soldering ::)

Wrong Polarity ::)

So you know the polarity on these diodes, by the way?
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

Spyderz20x6 said:
[quote author=CharlieMurphi link=1214270582/0#7 date=1214424538]Ok so following the video tutorial that I just linked here, I used the 5.6ohm 1/2 watt resistor and the diode was extremely dim. Does that mean that the diode is shot or that I need a different resistor? It still lights up barely. This is the third time that this has happened. I just cant keep spending money left and right burning these things up. What am I doing wrong here! I followed the video tutorial above..EXACT..?
Soldering ::)

Wrong Polarity ::)

So you know the polarity on these diodes, by the way?[/quote]

Yes I do know the polarity at least ;D

With the pins facing you, the case common pin is at the 12 O'clock position. That is the negative pin. The pin that is to the left, at the 7 O'clock spot, is the positive pin. The other pin, at 4 O'clock is a no connection pin. I have wired 3 diodes up in this fashion w/ a resistor only (no capacitors) to the original dorcy Jr. driver and have had no luck. I know that the pins have not touched or anything like that. I give :-?
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

Spyderz20x6 said:
Wrong Polarity ::)

So you know the polarity on these diodes, by the way?

If that were the case he wouldn't be getting a "dim beam", he'd be getting no beam.

I'm not familiar with kenom's dorcy guide, and the site the video is on is blocked from my workplace, so I can't really offer help there, but have you tried checking the current and voltage going through the diode?

You'll want to put your multimeter on the "current" setting, which may be labeled "DC mA" or it may have a couple settings for different ranges like "100mA" and so forth... You'll want to use a range higher than 400mA. Hook the multimeter in series with the laser diode.. so the multimeter itself is bridging the connection between one side of the laser and the corresponding pin on the driver.
To measure voltage you'll want to set your multimeter to voltage mode, "DC Volts" or such.. then measure in parallel with the diode, ie: the diode is hooked up directly to the driver and you connect the multimeter's pins to the + and - pin on the laser.

From what I gather, 300-400mA @ 2.5-3v is a normal range for a senkat diode... If it's much lower than that, there's a problem with your driver or something. If all else fails, maybe you might want to build a DDL driver, or buy a premade one from the b/s/t board.

BTW: Have you been using the same driver built into the same dorcy for every one of the diodes you burnt? There may be something wrong with it, it may have been damaged by being powered on with no load, or maybe short circuited or something, thus killing any laser you plug into it.
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

I have been using the same dorcy jr. for all 3 diodes. Im not sure if there is a problem with the Dorcy as I soldered the original led that came with it back into place and it powered up without a problem. Its just when I use a diode (with a resistor) there becomes a problem.
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

pseudolobster said:
[quote author=Spyderz20x6 link=1214270582/0#9 date=1214448802]Wrong Polarity ::)

So you know the polarity on these diodes, by the way?

If that were the case he wouldn't be getting a "dim beam", he'd be getting no beam.
[/quote]

Ooooooooooooooooh yeeeeeeeeeeeaaaaaaaaaaaah.... :-[
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

CharlieMurphi said:
I have been using the same dorcy jr. for all 3 diodes. Im not sure if there is a problem with the Dorcy as I soldered the original led that came with it back into place and it powered up without a problem. Its just when I use a diode (with a resistor) there becomes a problem.

semantic detail: both the LED and the laser are diodes.

Anyways, LED's have much less strict requirements and can handle a lot more abuse than a laser diode.. The fact the flashlight works means nothing. It may well be giving off much higher current than it's supposed to and the LED isn't dying like the lasers did.. or, maybe it's too low of current and the drop in brightness isn't nearly as noticeable with the LED.

The only way to get to the root of the problem is by testing what current the laser is drawing, maybe trying the lasers with a different driver. It might also help if you could post some pics of your setup so maybe we can spot if you're doing anything that's obviously wrong
 
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Re: Need help w/ choosing resistor for my Dorcy Jr

as pseudolobster stated earlier, you should try another flashlight, or you could buy one of Rkcstr's drivers (for like $7) and use that instead of the Dorcy driver, his drivers are great little things, especially for red diodes.

good luck.
 




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