# Charge capacitor with static electricity

Can i charge a capacitor fully with only static electricity? I already took a look at: Electrostatically charging a capacitor and How to charge a capacitor with static electricity? but i'm not sure this answers my question fully. Can you explain to me if it is possible to charge a capacitor from for example a wimshurst machine? What needs to be taken care when the capacity of the cap changes (i.e. if one time i have 100nF and a different one has 1000uF)? Im trying to charge a homemade foil capacitor and before building a bigger one I would like to know if doing this is feasible and what specifications i should aim for. By that approach I want to avoid building a voltage multiplier or other high voltage supplies.

• Very interesting question because it brought me back, a bit. Google easily found this link: Electrostatic Machines. That link is a compendium of various machines, many of which the author has built and experimented with. Worth going through (at least, to me.)
– jonk
Commented Sep 3, 2018 at 20:20
• On the wimshurst site there is this program: coe.ufrj.br/~acmq/programs/wmd.zip . I tried it out but im not yet sure what to do with those numbers. Could you maybe explain to me how I could go from these outputs to a calculation for charging a capcitor? For the sample in the program it states it outputs 17.08uA. Does this even help me with calculating the time? In another post I get I=VbRe−t/RC (for calculating how much amps will drawn with a fixed voltage supply). Im almost sure I cannot take this formula and just solve for the voltage that will be in the cap. Commented Sep 3, 2018 at 20:56
• That program doesn't accept specs for caps (or Leyden jars.) However, having them with larger values provides heavier-looking sparks. Much depends on the environment (humidity, atmospheric pressure, surrounding gas type, etc) that I don't think you will get an accurate answer about timing without a lot more experimental control/detail and a heavy amount of mathematics and the application of several physical theories to the problem. See, e.g., physics of gas discharge.
– jonk
Commented Sep 3, 2018 at 21:18