I have asked here a month ago regarding measurement of very low current. I was told that Amper-Meters today has this resistance in series that will cause a voltage drop, hence you can't measure a very low current.
So what happened with my Fluke is a very strange thing. If I put it on the scale of 2mA, or even 20mA, and try to measure current in my PCB, I get many resets of the MCU because the voltage is dropping.
But I discovered something else, if I put the scale on the Ampere meter to be in 20A, then the PCB is working and I can measure the current (!).
So my questions are:
Why is it working only with a scale of 20A ?
Are the measurements good? Can you count on them? I can tell that the LCD shows a curent of 0.03 in this scale, that means its about 30uA? (that's what I expect)