Found in a 1980s American documentation, this circuit uses programmable unijunction transistors of the time. The time interval obtained depends on the capacitors that can be changed.
The circuit presented makes use of the LM340 and a power transistor that can be the 2N2955 or more...
This sensitive circuit was found in the June 1995 Electronics Now magazine. R1 can be from 10k to 1M...
We found this circuit in a 1968 Electronics World. The potentiometer should be set to trigger the SCR...