This precision circuit was found in ancient American documentation. The most critical component is the PMOS transistor. The power supply must be symmetrical.
This sensor circuit for currents of the order of nanoamperes was found in an American...
The sensor of this circuit is an NTC of 20 to 50 k resistance at room temperature. The circuit is from a...
This circuit is suggested by Texas Instruments in his Optoelectronics Sourcebook. The transistors...