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 is a driver for R-2R network of AD converters. We found it in manufacturer...
This circuit was found in an American publication from the 60's. The transistor is made of...
This circuit produces an audio tone on the speaker or magnetic capsule. Rx must be such that added...