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.
The S-meter is signal strength meter, coupled to telecommunications receivers to indicate the...
This circuit is suggested by Motorola, making it possible to use an optical coupler of type 4N26...
Dynamic analyzer is another name given to a signal follower or signal chaser. This circuit is from...