This source was originally suggested by Delco in a 1969 documentation to power amplifiers up to 50 W. The transistors are of the time admitting modern equivalents.
This simple audio signal tracer or follower can be made with a BC548 instead of the original...
This circuit is from a 1982 publication. This is a way to stop 4017 at the end of a counting...
This circuit with analog indicator and diode bridge was found in Radio Electronics magazine from...