This circuit is from a Mallory 1968’s documentation. The integrated circuit is of the time and the transistor admits equivalents.
The author has many books he had written in Eglish (See the Biography) published by famous...
This circuit is from an old publication of the 70's. It can be implemented with modern transistors like the...
This configuration often addressed on this site is from a 2000 documentation. The circuit can be...