Wondering what the voltage on this PEMF machine is

[wirehead_freenode]

Is this really 990V? Given that the plug voltage is 120V.



And, what would putting 1 more 220/400V capacitor and rectifier yield, voltage-wise? My aim is around 1100V. Maybe 1200V.

[srb1954]

Yes, given sufficient time for the caps to charge to their full voltage. An additional stage would further boost the output voltage but at the expense of further extending the time to charge up to full voltage.

This is an absolutely lethal circuit and extreme care should be taken with it. The whole circuit should be enclosed in a suitable box with 2 safety interlock switches on the cover to both disconnect the mains supply and discharge the main capacitor through a lower value bleeder resistor, say 10k 100W.

With only the 1Meg bleeder resistor shown the main reservoir capacitors could potentially retain sufficient charge to deliver a fatal shock for over an hour after the mains is disconnected. It would be better to place additional bleeder resistors of say 47k 2W across each of the 7500uF capacitors. This would help equalise the voltage sharing across the 4 capacitors and provide a faster safety discharge. Even so, in the absence of an additional door interlock discharge circuit, the main capacitor could still deliver a fatal shock for up to 10min after the power is disconnected.

[Harfner]

Look for "villard cascade" for an explanation on how it works. That was often used in CRTs for high voltages generation.
BUT : Do not do it the way shown in the schematic. Aside from the insufficient bleeder resistors, the circuit is wired to mains without anything limiting power consumption. This gives you a good chance to burn up your lab in addition to electrocuting yourself.

What are you trying to achive? (There are ways to produce 1200V, even from a small battery)