This timer with two unijunction transistors and one SCR was found in an American documentation from 1964. The unijunction transistors could be the 2N2646.
We found this circuit at Modern Electronics in January 1991. The magazine no longer exists, but...
Found in a 90's EDN, this circuit can be used as a shield. The components depend on the MOSFETs...
This circuit will trigger an audible warning signal after the end of the pre-programmed timing. Using...