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.
This circuit employs an old germanium transistor. The circuit is from a 1950s publication and uses...
We found this circuit in an English documentation from the 80's. Transistors can be modern...
This circuit is from 1999 documentation. The integrated circuit used is not very common today. Both...