I am experimenting with a low power battery design ATtiny84 and I am using a Pololu USB AVR ISP Programmer. Pololu USB AVR Programmer v2.1
I read Nick Gammon's excellent articles on the procedures to reduce the power: Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors and I now want to monitor the effects of the measures I take but I cannot measure currents below about 2 micro amp with my Fluke 79 II meter.
I looked at the device https://www.eevblog.com/product/ucurrentgold/ but it appears to be out of production and a bit expensive for me anyway. I have obtained, on loan, a Keithley 485 Picoammeter http://www.tunl.duke.edu/documents/public/electronics/Keithley/keithley_485_picoammeter_manual.pdf which appears to offer the same features as the ucurrentgold.
The problem I have is if I leave the Pololu ISP plug attached to my circuit the Keithley reads over range (whereas my Fluke does not) so I have to remove the ISP plug after each programme download which is a bit of a faf.
If anybody has experience of measuring this type of low current I would appreciate advice to remove the need to unplug the ISP plug each time.
Maybe I am not connecting the Picoammeter in the correct way, I have it in the negative supply line of my power supply, I tried it in the positive supply but it was no better.