You are totally correct Balaur ...
In this case if I start the Italian idea I will need a 500uA meter, and no extra amplification stage.
Thanks for the info..
The good part is that I have not start anything yet,
I would prefer to make a full scale ESR tester, and not to convert a multimeter.
The IC1=TL084 needs more voltage, like steady 9-10V .
And so it can not be powered by batteries if you seek 100% success.
But the first design it can be powered with 9V or less.
Any way, there is still some time for suggestions .