This circuit is from Mullard 1969 documentation. The circuit operates at a relatively high supply voltage and has a 10 Vpp output. The transistors are of the time, but admit equivalents.
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...