2 diodes, both dim? (Now w/ Pics)

[Gazoo]

You can measure between the heatsink and the adj. as Rog suggested, or between the adj. and vout. Vout is tied to the heatsink.

You need to correct the position of your resistors. You should definitely be getting a reading of 1.25 volts between vout and the adj.

Take a look at the following pictorial. Combined with what Rog has explained, it should become more clear how to properly wire things up.

 

[Gazoo]

Oh and one more thing..I noticed you are using 4 batteries. The diode should still lase but the regulator will be dropping out as it requires 6 volts in this application. You really need to use 6 batteries.

 

[boost_dependent]

Oh and one more thing..I noticed you are using 4 batteries. The diode should still lase but the regulator will be dropping out as it requires 6 volts in this application. You really need to use 6 batteries.

why 6 batteries? I thought all I needed was 6V ?? 4 1.5v batteries = 6V are you saying I need 9V??? then why not just use a 9V battery?

yeah, I'll try and reposition the resistors when I get a chance.

 

[Gazoo]

Because the batteries sag as soon as current is drawn from them. The best to use is 6 nimh batteries. A 9 volt battery will not work because it can not handle the amount of current very well. So it might last a few minutes and it too will sag quickly. Look at the voltage on your 4 batteries after you get everything fixed.. you will not see 6 volts with the laser running.

 

[boost_dependent]

well, if the laser is supposed to operate at 2.85v (or something around that?) then wouldn't you see 2.8v and not the Voltage of the batteries?

I hooked the resistors up correct now and still I do not see any voltage by reading between the heatsink and Adj pin. I only see voltage if I go to ground then pin by pin.

 

[Gazoo]

The regulator's dropout voltage can be as high as three volts. So if you want to operate your diode at 2.8 volts, when your batteries sink below 5.8 volts... what do you think will happen? The voltage going to your diode will begin to drop too.

One way to verify you have enough voltage going to the regulator is to measure between the output and adjust..you should see 1.25 volts there. If it is less then your regulator is dropping out.

Try measuring again between the output and adjust of the voltage regulator right at the pins and let us know what the voltage is.

 

[boost_dependent]

ahh, I was measuring with the laser off. When I have the laser on and measure I get 1.25V

 

[amkdeath]

yea man gazoo is like the stephen hawking of these DDL drivers, so I wouldnt recommend arguing, cuz hes gonna be right in the end.

for 3v to the diode, you need 6v input to the driver, because of the voltage drop.

using 6NiMH batteries would be the best way to go

as I recall you are using N batteries?? or was that in another thread... anyways, N batteries I dont think would supply enought current...

 

[boost_dependent]

yeah, I'm using 4 N batteries.
With the pot at highest resistance I am reading about 45mA.
With the pot at its least resistance I am reading about 247mA.
And 1.25V between vout and adj.

 

[amkdeath]

yeah, I'm using 4 N batteries.  
With the pot at highest resistance I am reading about 45mA.  
With the pot at its least resistance I am reading about 247mA.
And 1.25V between vout and adj.

and im guessing your soldering is waht caused you to kill your diode IF it is dead.

BTW, what load are you using to test your current??

 

[amkdeath]

from your dot pics im guessing your diode is not dead, try doing the 12ft one on a white wall, its hard to tell when the surrounding is black and the camera is flodded with red. from the pics it looks like your diode is not dim... im confused...

 

[boost_dependent]

Pics? Yeah, they were posted already. No one said anything about them though....


My soldering killed the diode? Hmm I doubt it. I touched the diode pins for all of a sec. with the iron. I even heat shrunk each lead of the diode.


Load? ummm I just went in series to obtain the mA

 

[boost_dependent]

well, I guess I shouldn't have cropped the pics. Makes the dot look better I guess.
Yeah it's dim. There is only about a night and day difference from when I had it hooked to the breadboard and then on the PCB.

 

[amkdeath]

Pics?  Yeah, they were posted already.  No one said anything about them though....


My soldering killed the diode?  Hmm I doubt it.  I touched the diode pins for all of a sec. with the iron.  I even heat shrunk each lead of the diode.  


Load?  ummm  I just went in series to obtain the mA

ur measuring wrong,

do this:

(- output from driver)--(IN4001)--(IN4001)--(IN4001)--(IN4001)--(- DMM probe)

(+ output from driver)--(+ DMM probe)

set it to the 10A range and and measure current with your driver on

regards,

amk

 

[boost_dependent]

[quote author=boost_dependent link=1200189971/15#27 date=1200285986]Pics? Yeah, they were posted already. No one said anything about them though....


My soldering killed the diode? Hmm I doubt it. I touched the diode pins for all of a sec. with the iron. I even heat shrunk each lead of the diode.


Load? ummm I just went in series to obtain the mA

ur measuring wrong,

do this:

(- output from driver)--(IN4001)--(IN4001)--(IN4001)--(IN4001)--(- DMM probe)

(+ output from driver)--(+ DMM probe)

set it to the 10A range and and measure current with your driver on

regards,

amk[/quote]

You mean I have to go and solder 4 more diodes in series just to measure the current?
What exactly is the - output of the driver?


Here are better pics

12ft away full power

4ft away full power

 

[amkdeath]

yes your diode is dead.
:'( :'(

BTW, do

DONT solder the silicone diodes to the LD, remove the whole LD, just leaving the 2 wires coming from your driver.

solder the silicone diodes, and measure current in series with them to get your ACTUAL mA. folo my diagram. just slapping the DMM probes ont the driver wont and i repeat WILL NOT give you correct mA, and will most likely hurt your DMM, as now your DMM is being used as the load.`