This circuit was found in a 80s American documentation. The zener diodes determine the points of action of each stage and the transistors can be general purpose types.
This circuit was obtained from an American documentation from the 1980s. The T1 triggering...
Found with variations on this site, this circuit was taken from an American documentation from the...
With the original components, suggested in a Motorola documentation from 1971, this circuit can...