In my previous professional life I had access to so-called source-measurement units. These are devices that allow to do four-quadrant measurement; e.g. they can provide positive or negative voltage and source or sink current. This in all four combination of it without needing to rewire.
Full flex SMU equipment is currently out of my budget and that's why I am looking at the AD5522 SMU chip that should allow to do these type of measurements on a budget.
In part 4 of my journey with the AD5522 evaluation board I now focused on the calibration of the board to get better accuracy. Afterwards I did show measurement accuracy up to a few nA by measuring the photo-sensitivity of the some selected LEDs.
I completed first tests with the development board after avoiding a SPI driver problem. I did use the board now to measure some diodes. I am using python notebooks on a Raspberry to combine measurement with the AD5522 with plotting of the data.
Details can be found in my blog posts on the topic: