I asked a similar question on youtube before I knew about this forum. I don't think Felix's suggestion of not using auto-ranging while probing the 1mV/nA,uA,mA voltage output will allow me to see enough range to look at a scope trace and see the difference between 2uA and 3uA and quickly after between 75mA and 80mA. However, I probably can run for a time on the nA range, store the trace and then run for a time on the mA range and store the trace. Because the current use patterns will typically have RF transmit spikes in them around 80mA and LED patterns, I can probably match up two separate runs. However, is it safe to put 80mA through the CurrentRanger in the nA mode, assuming I don't care that the voltage output circuitry saturates in that case?
Or perhaps I can use the 'g' option firmware and an optoisolater on the GPIO?
Isaac Davenport
I am not sure if this is the place to ask. I just ordered a CurrentRanger. I need to look at sleep currents at a couple uA, uController wake currents at a couple mA, LED currents of a dozen mA in tens of ms pulses, and radio transmit current draws of 80 mA in tens of uS pulses of current draw. As these overlay on one another and the CurrentRanger autoranges, how can I know if what I have on the oscilloscope is show a mV per nA or uA or mA? Do I need to probe the LED outputs for the three ranges at the same time that I probe the real time voltage output? Nice creation BTW, I am looking forward to putting it to use.
Felix Rusu
Please DO NOT probe the LEDs while probing the output, this is a good way to damage the CR since the grounds of the output/LEDs/USB/input are different so doing that will create ground loops. I would suggest just placing the CR in manual mA mode, then it will give you a good clear output and you'll know how it looks like when it wakes up. Then for the sleep part go in uA mode - the CR should not