Voltage Doublers
I built some simple voltage doublers to see what wave forms result.
I used my trusty doorbell transformer to produce 60Hz, 21.6VAC relatively safe alternating current voltage to double.
Villard Circuit
Components: 1N4001 diode, 3.3 µF 370VAC capacitor. The capacitor is a furnace motor start/run capacitor, labeled 5 µF, but my multimeter measures it at 3.3 µF
Above, my jumpered-together Villard circuit. You can just barely see the 1N4001 diode between ends of two yellow jumpers. The ground clip of the oscilloscope probe is on one end of the diode.
This is pretty clearly the 60Hz sine wave transformer output bumped up - the trough voltage is 0V instead of -32V.
The oscilloscope screen says 6.40V peak. I had the probes switched to 10x attenuation, hence 64.0V peak voltage. My Commercial Electric multimeter read 30.6VDC across the diode. That’s not 2 * 21.6V, but if I look at RMS voltage, I get 64.0/√(2) = 45.3V, which is a little more than 2 * 21.6V.
Greinacher Circuit
Components: 1N4001 diodes, 67 nF capacitors as measured by a multimeter.
That’s a close-up of the circuit on a breadboard. It’s oriented the same as the schematic above. AC from the doorbell transformer come in on the gray wires from the left. DC positive is the top orange wire (right next to the “11”). DC negative is the bottom orange wire.
That’s an 18.5V ripple, Vpeak of 40.5V, trough 22V. I wonder if I should use bigger capacitors.
My Commercial Electric multimeter read 51.9VDC at the circuit’s outputs, which basically doesn’t make any sense. Why would the DC voltage be greater than the peak ripple?
This is a different wave form than the Villard circuit, and the full wave bridge rectifier, which was at 120 Hz as well as a 29V peak and 29V ripple.
Image Attributions
Villard Circuit By Spinningspark at English Wikipedia - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=41598208
Greinacher Circuit By Spinningspark at English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=41704318