We found this circuit in the May 1983 issue of Radio Electronics magazine. The integrated circuits are from that time. Note the supply voltage.
This delay circuit for a sound system was found in the December 1990 Radio Electronics magazine as part...
This 80's National Semiconductor circuit uses an era integrated circuit and symmetrical 5V power...
This wired intercom was found in a 1960 Sylvania transistor manual. The transformers are the type...