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Power Profile Kit II measures 1.5microAmps when disconnected

vofitserov

I'd like to use Power Profiler to measure really low currents (watches) ~0.4 microAmps. 

However, Power Profiler II measures 1.5microAmps even when disconnected with or without voltage supply.

I've tried using Advanced Settings to reduce gain for R1 but even with lowest setting (0.9) the kit measures 1.3 microAmps when disconnected.

Is there way to calibrate/reset the device to make sure it has true zero?  

 

Parents
  • 0

    I presume you mean that your DUT is effectively an "open circuit" when you say "disconnected".

    You cannot measure *current* into an open circuit.  Measuring current into a short circuit is also problematic.  This is not a voltmeter.

    If you wish to do a quick sanity check, put a 10 Megaohm or 100 Megaohm resistor as the DUT.  This gives you a complete circuit that you can check the current on.

    Hope this helps.

  • 0 in reply to Andrew Lentvorski

    I've connected 101.2K resistor with 800mv supply, got 9.09 microAmp (expected 7.9microAmps) with noise from 9.0 to 9.2 microAmp. This can't be right. 

     

Reply Children
  • 0 in reply to vofitserov

    Why not?  Have you checked the specs on the Power Profiler Kit II?

    9 microAmp is right about what would be measured with a 100K resistor with a 10% tolerance is the tolerance is on the low side.  A 20% tolerance is easily in range.

    Resolution of the board at the requested range is 0.2uA so that looks correct.

    Accuracy is +/- 10%.  Offset is 2%.

    101.2K resistors don't exist, so you are citing a measurement that *also* has it's own inaccuracy.

    If you want accurate measurements near instrument limits, you need to understand the limitations of your instruments.

  • 0 in reply to Andrew Lentvorski

    I've measured 100K resistor with digital multimeter (EX330 that claims 0.50% accuracy), got 101.2K. I expected that without the circuit the current should be measured as 0uA but board consistently shows 1.3uA. I could be looking at the ghosts but if I substract 1.3uA from 9.1uA measured at 101.2K resistor I got expected 7.8uA (101.2K over 0.8V). I am speculating, but there is something in the my PPK that leaks about 1.3uA that adds to the measurement. I've asked distributor to send me another instance, I'll check in a few days and report what I find. 

  • 0 in reply to vofitserov

    Ok. Let us know your findings with the new PPK.

    Regards

    Kazi Afroza Sultana

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