This circuit was found in a 1966’s American publication. What it does is to receive a pulse and keep it for intervals of up to 1 minute at the output.
We found this circuit in a documentation from the 75s. Transistors admit equivalents such as BC558...
This circuit was found in a 90s Electronic Engineering. The circuit has the tube's critical...
This circuit was found in an 80's Electronic Design. It amplifies TTL fast signals for a coaxial...