LEDing a diode

[richard86]

Ok quick question.

I have a 1w diode and driver board. Was working fine..
Now the diode is dim.

Wen turned on it blinks bright and then stays dim.
Turn it off then on.. Bright for a split secound them stays dims.

With the lens off. Shining on a wall it looks fine just dim?

I dont have another driver to test with as im new to this hobby and waiting for all my orders to come in

Just hoping its the driver not the diode. Obviously because of costs.


Thanks.

Richard.

 

[ApexProxy]

It sounds to me like its either your power source or the driver. If the diode was LEDd it wouldn't go bright at first it would just be dim from the beginning. Try switching your power source to one you know 100% sure works perfect.

 

[Flaminpyro]

Thank you for your answers. Now I've just to wait for the cells (it's taking so long!). I'll post some pics soon (I hope ).

When you do post some more pictures please click and copy on the FORUM link on image-shack and paste the picture on here, see>

 

[richard86]

Im waiting on a order for some driver boards so time will tell

Im gunna try a multimeter on the driver board and see what power its putting out.


Thanks

It sounds to me like its either your power source or the driver. If the diode was LEDd it wouldn't go bright at first it would just be dim from the beginning. Try switching your power source to one you know 100% sure works perfect.

 

[richard86]

Ok so ive just connected the driver to a multimeter and its out put is..

8.37V
1.9A

It was runing on two 18350 3.7V 1200mAh batterys.

Guessing my diode is the problem?



Richard

 

[ApexProxy]

The only way you can test what current the driver is actively giving your diode is to cut your diode out of the circuit and run the driver on a test load. Testing what your driver is drawing from your batteries during operation works as well. Otherwise you would have to place your multimeter in series to your diode by cutting a wire off the diode lead and bridging the connection with your multimeter. If you do this wrong you can fry your driver and or diode. If you decide to do it the third method make sure you do things in this order:

-remove all power to the laser
-cut the positive lead going to your diode from your driver
-place your multimeter in series to your diode(attach one lead of your multimeter to the wire leading off the diode and the other leading from the driver that used to go to the diode). I would suggest using alligator clips to avoid connection instabilities that would kill your diode.
-set your multimeter to amperage measurement mode and turn it on
-reconnect main power and turn on your laser
-whatever your multimeter reads is how much your diode is drawing
-remove main power
-remove your multimeter
-briefly touch the positive lead coming from the driver to the negative lead also coming from the driver to short it out to insure no residual power remains
-reconnect the driver to your diode and solder the wires back together using heatshrink tubing(best way) or a little electrical tape

If your diode is drawing far less than it should be its likely your problem is the driver or your power source. If its drawing near(roughly) normal power and its still super dim its likely LEDd and done for.

Please, someone correct me if I am off on something. I have done basic tests like this in the past and so far I haven't been wrong but it may not always be true for every situation.

EDIT: So that is what your driver is drawing from your battery or did you hook your driver up to a test load and measure it that way?

 

[richard86]

I took the diode off and put the multimeter on. So thats what the driver is putting out.
I will try puting the diode on aswell cos thinking about it.
The diode flashes bright then stays dim = soon as it draws current it carnt handle it im guessing?

So the test i just did was pointless haha.
I will try it with a diode on.
Give me a few mins and il post back


Richard

 

[ApexProxy]

Those readings will likely not be quite right since in order to test a driver it has to be under a real load. Your multimeter is not a real load and will not give you correct readings. That is why I suggested testing it with the diode actually running since that is a real load.

It is not too likely that your diode cant handle 1.8A like the driver is supposed to be limited to. It is however possible that your diode can't handle 1.9A if that really is what your driver is driving it at.

 

[richard86]

Ok so with the diode on.
I get the same volts but no amps? And the diode dont even turn on not even dim?
I took the multimeter off and wired it back up and its the same.

Bright for a split second then dim.


Richard

 

[ApexProxy]

Are you sure you have the multimeter set correctly? You generally have to move the test lead on the multimeter to the fused terminal to read amperage, especially amperage above a few mA.

 

[richard86]

Im not sure if its set right but it reads the batterys as 1.2a and thats what they are.
I tryed the driver on a cree light and that worked fine.
I connected the multimeter and the volts was 6.something?
The amps still was at 0 and the cree light wasnt on.
Maybe my multimeter is broke or im doing something wrong?

Richard

 

[ApexProxy]

Then something is wrong with the way you are setting up the multimeter.

Also, don't stick a multimeter directly to a battery since you will pretty much make the battery crap itself trying to release as much current as your multimeter will take which can damage your multimeter and battery.

Put the multimeter inline with the diode as though your multimeter was a laser diode itself and you wanted to power two diodes at once.

Connect the driver's positive lead to your multimeter's negative lead and then connect your multimeter's positive lead to your diode's positive lead. Then set your multimeter to measure amperage and power it up.

Also remember that every time you disconnect your diode you have to short out your driver before reconnecting it. Also never disconnect/reconnect your diode while the driver is powered and never power your driver unless it is connected to your diode or a real test load.

Since the CREE LED worked on the driver you may just have an LEDd diode. First try what I suggested above. If it still doesn't read any current try that same thing but replace the laser diode with your CREE LED and see if it powers it up. If not your multimeter is messed up or you aren't setting it up right. You could try posting a picture of your multimeter face with it set to test amperage and I can tell you if its right or wrong.

 

[richard86]

I could email you a picture of it? As im using my phone and ive uploaded pictures of something im selling to photobucket and its not on there yet? So not sure how long that will take or if its worked.

Anyway. I tryed both the above and with the multimeter connected i get no reading of amps? And no diode or led lighting up. Volts works fine.

 

[richard86]

 

[ApexProxy]

The ground test lead needs to be moved over to the left terminal and the dial needs to be moved one notch clockwise. You may also have to move your positive test lead one terminal to the left as well.

 

[richard86]

Ive tried that i think.. I will try it tomorrow.

I havnt moved the red lead though As when you pull them out they all have black terminals apart from the red wire. It has a red terminal? So i guessed that one only goes in that hole


Thanks for your help.

I will update tomorrow as and when i do more tests.


Richard.