This PNP transistor power stage was found in the May 1969 issue of Radio Electronics magazine. The circuit uses a transformer for excitation and requires 10W input for full output power.
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...