Current measurement Thingy 91

[ActiTAG]

Hello, everyone,

I got a Thingy91 and I would have liked to be able to measure the current that passes through the NB-IoT modem, for that, I followed this tutorial :

https://infocenter.nordicsemi.com/topic/ug_thingy91/UG/thingy91/hw_description/hw_power_current_measurement.html

Here the result:

 

I cut the SB3 bridge and soldered headers to make the measurements. I checked the soldering, headers, cables, everything is functional. 

If I use a Jumper on my header, it works, I can use my debugger and program with it, if a program is flashed it works and if I want to update the firmware too. But if I connect my multimeter to pins, it does not work anymore. (I check the connection). Do any of you have an idea of the problem? Did I miss any information?  Thank you.

[awneil]

A multimeter isn't going to give you useful readings - the current is very "bursty".

You need something like this:

www.nordicsemi.com/.../Power-Profiler-Kit-2

What range did you have the meter set to?

A low current range will likely have too high a burden voltage:

https://zone.ni.com/reference/en-XX/help/370384V-01/dmm/burden_voltage/#:~:text=Burden%20voltage%20is%20the%20voltage,kept%20as%20low%20as%20possible.

[ActiTAG]

Thank you very much! I plug it into 20Amax and now it's working, I was on the µA/mA.