laser current measurement

[reloader45]

Hello,

because I hate to cut connections to measure the current to a laser diode, I bought a cheap clamp multimeter.
Attached you will see a picture with a comparison between the clamp meter and the power supply. If you set the multimeter to zero before, the results are nice, even at low currents. Youn can measure currents up to 100 A. That should be sufficient for further projects.

At the other pictures you see the behavior of the simplest driver (LM 317 with a 10 Ohm resistor) while switching the power on and off.
The current change is very smooth, no spikes to see. For low current application this seems to be a very good solution.




best regards

Edgar

 

[paul1598419]

Yeah, I've got a clamp meter too. I rarely use it, though. I setup all my drivers using a dummy load, so I never need it.

 

[reloader45]

Hello,

I have also a dummy load with a 0,1 Ohm shunt to measure the current, but I like the easy work with this clamp.
I set my 5500 driver for my 465 nm diode to 2,5 A with the dummy load and the clamp.
For short time measurements the oscilloscope is nice. The problem is the 270 page manual. Today I found the single event recording mode. So I made the two switching measurments.


best regards

Edgar

 

[paul1598419]

I also have adummy load with a 0.1 ohm sense resistor, but for low power drivers, under 3 amps, I use another with a 1 ohm sense resistor. It works better for lower power drivers and is easier to read than the one tenth of my higher power load.