What changes must be made to power this circuit from 120VAC mains rather than 240VAC mains like shown in the schematic?: https://www.redcircuits.com/Page27.htm Thank you.
Rain,
You could vary the reactance value C1 or as an alternate use a step-up transformer, since the current drawn is less. But also be aware that this circuit is for 50 hz mains (I am not sure if this will make a difference, I am just pointing it out).
The circuit probably work without modification. The critical component C1, this must be X2 type (rated for 270V AC 50Hz). For higher output load increase this capacitor value 470 or 680nF.
well, dreamproject it would have made a difference if there would have been an induction motor in the circuit. with motors the frequency matters alot. you can easily use a 120V 60Hz induction motor with a 240V 50Hz mains by stepping the 240 down to 120 but the motor will be operating at 50Hz and it will give less rpm and torque. you could use a complicated (and expensive) circuit and convert the 50Hz into 60Hz but the total cost will be greater than buying a new 240V 50Hz motor.
As already suggested, the only change required is to C1, which needs to be a higher value. The 50/60Hz will make no difference, it has no relevance in this circuit - which operates internally on purely DC.