This circuit is designed to measure very weak currents, in the order of picoamperes. We found it in an American documentation from the 80s. The integrated circuit is from that time.
This commercial transistor radio was manufactured by RCA in the 1960s. The circuit has only 4...
This circuit has a normally low output that is triggered by a high pulse. The circuit is from...
Suggested by a 90s Popular Electronics this circuit is intended to receive volleys or whistles...