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.
Found in a 1965 Radio Shack documentation this oscillator can be used with modern general purpose...
In the figure we have a voltage / frequency converter circuit that can be used as a transducer interface...
This small stereo amplifier for headphones was found in a documentation on integrated circuits from...