We find this circuit in a 1980s Linear Technology documentation. The circuit can be implemented on the basis of more modern equivalent components.
July 2017 - Mouser Electronics announced the availability of Littelfuse's GEN2 series Schottky...
This configuration is suggested by Mullard (Philips) in an old manual of 555 integrated circuits....
We found this circuit in a Popular Electronics of the 90s. Its purpose is to detect when it locks...