This type of logic is no longer used today. The circuit is from an old American publication and the integrated circuit is uncommon today. Diodes are general-purpose tpes.
This circuit was obtained from a Hands-On Electronics, an American magazine from January 1987. The...
This receiver for listening to the TR-23 phone was manufactured in Japan in the 1960s. The circuit is...
This astable multivibrator with an operational one at the time was found in the National...