Can i safely test the opperating current (ma) between flex drive output leads?

[Kaokin]

I have a diode connected to a flex drive v5. Is it safe to measure the current between the output leads of the flexdrive WHILE the diode is connected and powered up?? I want to read the exact voltage and current that the diode is recieving and want to make sure that this is most importantly SAFE and (almost as important) ACCURATE. i am extremely nervous about frying my GGW diode!!! Thanks in advance!!

 

[Bionic-Badger]

Stick with the dummy load. The Flexdrive works by creating as much current as is set by the pot on the driver, irrespective of load. That's why if you power it up without a diode on the output you can burn out your flexdrive.

So I would use your dummy load and measure the current across the resistor using that. You also don't want to put your multimeter inline with your laser diode, as it is liable to cause some accident that will fry your laser diode. The best way is to always measure across a known resistance. I think all the Flexdrives have a resistor on them to measure across as well (check the manual), so you can use that after the laser has been soldered on.

 

[Hemlock_Mike]

You can measure the voltage ONLY between the output leads of the drive. As said many times, "forget the damn voltage" these are current controlled. Every LD has a slightly different junction voltage for the current it is drawing.
The current metering must be done in a solid connection series in a diode leg connection with the meter in a correct range mA configuration. I have done it this way for years.

HMike

OOPS... I see that you are a noobe here and the info provided above by BBadger is likely your best approach to your build. I thought you wanted specific info on your diode.
The dummy load is a good approximation of a LD when using a current driver.

 

[Flaminpyro]

A pyro dummy load is the way to go, I can see your wanting to know just how much current is going into your diode, what I'm about to tell you I have done befor so I know this method works fine. you don't want any thing comming loose between your diode and the drive while the power is applied or you will prob kill the diode with a spike so everything must be soldered !!! what I do is solder the 1st lead of the laser diode to the driver the other lead of the laser diode is soldered to a 1.0 ohm 1watt resitor the other end of the resistor is soldered to the driver where you would have soldered the 2nd lead of the laser diode. now you can put your VOM on milivolts and connect it across the resistor and read the ma going to your LD. Hope this helps !

Peace All pyro...

 

[jayrob]

I have a diode connected to a flex drive v5. Is it safe to measure the current between the output leads of the flexdrive WHILE the diode is connected and powered up?? I want to read the exact voltage and current that the diode is recieving and want to make sure that this is most importantly SAFE and (almost as important) ACCURATE. i am extremely nervous about frying my GGW diode!!! Thanks in advance!!

Here's the link I always like to post for this question:
It can be done - Laser driver

There, rog8811 shows great diagrams and gives instruction on testing current with a test load.

He shows a DDL driver, but it is the exact same procedure for a FlexDrive. And you can use Pyro's test load as well...

 

[Kaokin]

Awesome Thanks for the replies... ill just place my trust in the test load for measuring the current

 

[lasersbee]

You will save a lot of Laser Diodes that way...
and possibly your FlexDrive..

Jerry