This sensor circuit for currents of the order of nanoamperes was found in an American documentation from the 1980s. The components are from that time.
Found in a 90s Radio Electronics this circuit requires precision resistors in the dividing...
Mouser Electronics is already providing new MOSFETs EF SIHx28N60EF of Vishay series for voltages...
The LMV321 is a low voltage operational amplifier from ON Semiconductor. The following diagram,...