This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
Found in Popular Electronics from the 90's, this circuit uses common components and can be easily...
This circuit was found in a 1973 publication. The SCR may be the TIC106 and must use a heat sink,...
This circuit was obtained from my Mechatronics Sourcebook, published in the United States. In it...