This circuit was found in an American magazine 73 for radio amateurs of the 80s. It is an automatic transmission circuit for telegraphy. The circuit is TTL.
Figure Bellow shows how to interface CMOS circuitos with TTL using the 4049 or 4050 IC. The power...
This circuit is from a manual from the 80's and the operational one used, uncommon nowadays, can...
Based on National Semiconductor's LM4130 reference circuit, this circuit was found in Internet...