The figure shows a remote-control receiver working the 27 MHz band, very popular in the 60’s. The circuit us from a February 1961 Radio Electronics magazine.
This was one of the National Semiconductor clock modules very popular in the 70s and 80s. In the...
This circuit is from 2001 documentation, serving to multiplex stereo signals for FM transmitters. The...
EDN magazine in a 90's issue published this TTL technology debouncer flip flop circuit, in this...