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.
Found on Popular Electronics this circuit has variations found throughout this site and section....
This charger sources currents in three ranges: 10 mA, 25 mA and 50 mA; Current is sellected...
This circuit, obtained from ancient English documentation, produces a pulse every 24 hours when a 50...