This circuit with unijunction transistors was found in a documentation from the 80's. The trigger times of the SCRs depend on the capacitors and are adjusted in the 5M (4M7) potentiometers.
With this circuit it is possible to accelerate the discharge of a capacitor in a unijunction...
This circuit was found in a Poptronics of the 90's. The circuit limits the load current to 0.6 A....
The circuit presented is from the 1993 Motorola Linear Interface ICs. Other operational may be...