This circuit is from a 1968 Electronic Design. The characteristics of the output transformer are not given and the transistors are of the time. The circuit provides a power of a few watts.
Indicated for applications with a PC, this circuit was obtained in an English publication in 1992....
This circuit of a 1969 Electronic Design uses RTL logic. The setting can be adapted to TTL. The...
This circuit with TTL compatible output was found in a 1968 US documentation. The circuit is...