The circuit presented is from a 1965 technical documentation. It is a power supply that utilizes thyratron tubes that are the equivalent of SCRs in the world of tubes.
We can say that it is a switched source in its valved version, capable of supplying voltages of values that are adjusted in a potentiometer of 100 k in a band that reaches the 400 V.
The critical components of this design, in addition to the common tubes are the thyratron PL2021, tubes and the transformer that has secondary 350 + 350 V with 200 mA or more.
Components subjected to high voltages, such as capacitors, must have compatible voltages. Also note that the transformer must have voltages for the tubes filaments.
In figure 1 we have the complete diagram of the power supply.
