This QST circuit generates 4 frequency signals according to the crystals used. Transistors admit equivalents although the indicated types can still be found with some ease.
This 1989 circuit activates a protection relay if one or two phases are missing from a three-phase...
This simple TTL electronic dice uses common anode displays. The circuit is from a March 1975 Radio...
This non-pulse alarm can be used as an event detector or even an alarm. The circuit can also be...