We found this circuit in a documentation about SCRs from the 70s. The circuit can be implemented with a SCR of the TIC type according to the maximum voltage that is desired at the output. High voltage is achieved with a transformer that has a primary according to the grid and a secondary according to the desired voltage. T1 has a secondary between 2.5 and 6 V with central socket. C1 should be tested with values between 220 nF and 470 nF. The SCR must be mounted on a heat sink.
