Circuits similar to this can be found in this section. This is from 1967 General Electric documentation. The main SCR must be fitted with a heat sink.
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
This configuration, already presented in other points of this section and website, is of a...
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...