Is this picoAmmeter useless?

[watchmaker]

https://www.aliexpress.us/item/3256805868333845.html?

Problem for me is the description is in Chinese.


Thanks,

Dewey

[EC8010]

Probably.

I've now made quite a few different electrometers, some going down to <1fA. But to learn how to make successful electrometers, you need one working one to use as a reference. Once you've learned how to get leakage currents down, you can make better electrometers than your "reference" one. Why is this relevant? Because when you want to measure little currents you need confidence in your measuring instrument, and if you can't even read the description of the instrument, how can you possibly have confidence?

[ivo]

I'd guess the technical resolution might go down to 10pA from the ADC bit depth, but likely any readings down at that absolute level would be junk.