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 1993 Electronics Hobbyst Handbook this circuit is a solution that we have already...
This circuit aims to increase the selectivity of receivers whose FI is 455 kHz. The circuit is...
This high current switching stage was found in a 1967 EEE. The power transistor is from that time....