This SCR circuit can operate on frequencies from 1 to 20 kHz. We found it in an American documentation from the 60's. The SCR must be according to the load. No information is given about the transformer.
This circuit includes the power supply from the power grid. We found it in Radio Electronics from...
We found this circuit in a 2003 publication. The indicated coil is for capturing the signals in an...
This circuit is from a 1967 publication. The configuration holds true for modern transistors having...