This is actually a full wave voltage doubler power supply. I takes a 120 volt AC and double it to 240 volts. When filtered, voltage level gets to about 90 to 95 percent of peak, which is voltage RMS times 1.414. I get about 330 volts out of this with a full load. the resistor before the first diode is 120 ohms at 5 watts. The diodes are standard silicon rectifiers with peak inverse voltage ratings of 500 volts at 1 amp. The circuit I have it in drains no more than 1/4 amp or 250 milliamps. The choke is about 2 Henries. The capacitors in parallel with the diodes are 0.1 microfarad 500 volt ceramic discs. The first filters (forming the doubler circuit) are each 200 volt 100 microfarads. The first main filter capacitor just before the choke is 20 microfarads at 450 volts, the one after the choke is 100 microfarads at 450 volts, and the one after the resistor, which is 40 ohms at 20 watts, is 250 microfarads at 450 volts. The total power out capability is about 65 watts (325 volts at about 200 milliamps).