This basic Schmitt trigger was found in an American publication from 1968. The circuit uses transistors from the time. Modern general-purpose types can be used.
In the figure we have a bistable multivibrator using an operational one. The circuit is from old...
This silencer or squelch preamp circuit was found in a documentation for radio amateurs. It...
We found this circuit in an American documentation from the 90s. Through an LED it indicates the...