Why won't my driver work?

[knimrod]

I've not had very good results with the Duracell CR123s in mine.. They are okay initially but after a short while the current starts falling off which is a clear indication that the regulator is dropping out due to a lack of voltage.  The RCR123s don't do this and are a much better choice IMHO.

 

[Gazoo]

LarryQ also had the same problem...when he switched to RCR123's the problem went away.

 

[amkdeath]

DUDE WARNING!!

u said the pin got disconnected, immediately cut off power, take the leads off diode, short the circuit, then securly resolder the leads onto the diode. if a lead is disconnected and then reconnected, (to the diode or whatnot) u will send a full cap discharge into the poor diode, killing it instantly.


If ur gonna use NiMH batts, use 6, 4 will sag.
I dont know about RCR 123's, but if gazoo says itl work it defenitely will.

regards,

amk

 

[spinout059]

Ok I got my driver rebuilty. I am using LM317, 1k pot, 35v capacitor, (2) 10ohm resistors and a 14001N diode. I tested it with no dummy load and got 240ma. I hook up my diode and get barely a light at all, not even visible at 1cm away. Oh and by the way I am using (2) cr123's. Help greatly appriciated! Thanks! (If you want I will post new pics of the new driver.)

 

[chido]

Post some pics man. ;D

 

[amkdeath]

Ok I got my driver rebuilty. I am using LM317, 1k pot, 35v capacitor, (2) 10ohm resistors and a 14001N diode. I tested it with no dummy load and got 240ma. I hook up my diode and get barely a light at all, not even visible at 1cm away. Oh and by the way I am using (2) cr123's. Help greatly appriciated! Thanks! (If you want I will post new pics of the new driver.)

when u measure mA's u need aload, u cant just hook it up to the DMM

change ur pot

make sure u got RCR123's, not CR123's

change ur pot.

regards,

amk

 

[spinout059]

[quote author=spinout059 link=1199823086/15#19 date=1200089050]Ok I got my driver rebuilty. I am using LM317, 1k pot, 35v capacitor, (2) 10ohm resistors and a 14001N diode. I tested it with no dummy load and got 240ma. I hook up my diode and get barely a light at all, not even visible at 1cm away. Oh and by the way I am using (2) cr123's. Help greatly appriciated! Thanks! (If you want I will post new pics of the new driver.)

when u measure mA's u need aload, u cant just hook it up to the DMM

change ur pot

make sure u got RCR123's, not CR123's

change ur pot.

regards,

amk[/quote]

amk, I am having a hard time understanding what you mean by "when u measure mA's u need aload, u cant just hook it up to the DMM". Can you please clarify? Thanks.

 

[chido]

http://www.laserpointerforums.com/forums/YaBB.pl?num=1197651171

 

[amkdeath]

 

[BlueFusion]

You won't get any output to the LD in that scenario. The dummy load (diodes) will take all the current. Get rid of the 1N4001 diodes and replace them with the laser diode and you're in business.

Those are useful for determining a good setting for the pot, as to getting the current right. But leaving them there while trying to run a laser diode is just not gonna work.

 

[amkdeath]

You won't get any output to the LD in that scenario. The dummy load (diodes) will take all the current. Get rid of the 1N4001 diodes and replace them with the laser diode and you're in business.

Those are useful for determining a good setting for the pot, as to getting the current right. But leaving them there while trying to run a laser diode is just not gonna work.

blue, we never said we were gonna put them on the diode...

if you read, he wanted a dummy load to test his circuit...

sorry if im misinterpreting ur post, but that was his question.

 

[BlueFusion]

Ah i see... It just seemed to me like in that picture he was planning to connect the diode over the dummy load which wouldnt work at all...

 

[rog8811]

I guess the picture posted by amk may suggest that the load is across the LD. But taken in contex with the thread it came from, that has been linked to and refered to, a number of times in this thread all the testing is simply explained.

@spinout For future reference you should really test your circuit before you connect the LD ( I know it is too late this time around). Follow the steps in the aforementioned thread, find out and note :-

The ref voltage (1.25v)

The voltage across the load diodes (3v ish)

The mv across the 1ohm resistor (0 to 250mv ish)

Once you have those figures post them here on the thread and we can see where there may be problems.

Regards rog8811

 

[amkdeath]

I guess the picture posted by amk may suggest that the load is across the LD. But taken in contex with the thread it came from, that has been linked to and refered to, a number of times in this thread all  the testing is simply explained.

@spinout For future reference you should really test your circuit before you connect the LD ( I know it is too late this time around). Follow the steps in the aforementioned thread, find out and note :-

The ref voltage   (1.25v)

The voltage across the load diodes  (3v ish)

The mv across the 1ohm resistor (0 to 250mv ish)

Once you have those figures post them here on the thread and we can see where there may be problems.

Regards rog8811

where it says V= to LD, it can be misleading as connect the LD< but it means: "what you get as a voltage reading is what ur dioed is getting voltage wise."

 

[rog8811]

where it says V= to LD, it can be misleading as connect the LD

In the post that the picture comes from it says:-

4) Attach the 4 diodes and resistor to where LD will eventually connect. If your reverse diode and capacitor are already connected to your LD you can connect your test assembly to the output from your fixed resistor and the neg of the battery.

I think with anything like this, directing the OP to the original thread is always best.
Although I fully understand why the picture was posted here as the OP seemed to ignore the advice to go there.

Regards rog8811