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 found in a documentation for radio amateurs from the year 70. Its purpose is to...
We got this circuit in an old publication from 1978. The circuit uses a phototransistor and an...
This simple transistor radio with only two germanium transistors was found in a Japanese magazine from...