This oscillator uses a crystal to set the frequency. The operating limit of the unijunction is in the order of 100 kHz. Power supply can be between 10 and 20V.
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...