Designing a 550 V, 3A DC power supply using a multiplier circuit

trini

Ok so i received the suggestion to get such a power supply by rigging a variac to a bridge rectifier, but variacs are rather expensive, so after some snooping around i came around this site:

http://www.scribd.com/doc/9779212/eb...c-power-supply

they basically just use a combination of capacitors and diodes to get a pseudo DC effect, and it is mentioned that by altering the values of capacitance, i can get the DC pulse trains i require, however they don't mention an exact relationship between the two. What i would like to know is if i use such a circuit, what formulae may i use to determine the size and amount of capacitors to use?

famousken

That circuit is called a Villard Cascade, the size of capacitors you decide to use depends on the frequency of the input and what is an acceptable amount of ripple, as well as how many stages your multiplier uses. It is also good practice to place bleeder resistors across each capacitor in the circuit as these voltages are potentially lethal. Here is a link to all the formulas you could want for capacitance.
http://en.wikipedia.org/wiki/Capacitance