This circuit was found in a 90’s 303 Circuits. The components are from the period and the heating system depends on the resistive element.
The circuit shown in the figure is suggested by Micrel, based on the MIC2570 boost voltage...
This circuit can work with almost any JFET. The circuit is from an Electronics Now from April...
This circuit should only be used with incandescent lamps and the SCR should be fitted with a heat...