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 from an old documentation includes the power supply for the 117 V power grid. It can be...
Found in a Popular Electronics from the 90s, this circuit presents the difficulty of obtaining the...
This ultra-simple 9 V power source was obtained in an Argentine publication of the 1970s, but it...