This circuit was obtained in a 1967 Electronics World. The components are still common today, the SCRs can be replaced by equivalents and the unijunction transistors the 2N2646.
In the figure we have a circuit suggested by National Semiconductor, using an operational...
For experiments with ionization chambers and Geiger valves this circuit generates high voltage from...
We found this circuit in a 1979 documentation, but it can be changed to use more modern...