How do you figure out how big of a capacitor you need for a voltage doubler circuit? I am putting together one for a 250 VA 24 volt transformer.

Labman,

Found this website with a decent explanation and formula to calc the farad .

http://ww1.microchip.com/downloads/en/DeviceDoc/41215a.pdf

Starts on page 29.

See if this is what you are looking for. Otherwise I found a great deal of info on the net, searching " calculate voltage doubler capacitance"