This game was found in an old Popular Electronics. The unijunction transistor can be 2N2646. The supply can be done with voltages from 6 to 12 V.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...