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.
This circuit is an excellent shield for microcontrollers and was found in the October 1987 Radio...
This fixed-time circuit, found in the 2006 documentation, activates a load after a certain time....
This circuit indicates when the monitored voltage drops below the value determined by the divider...