Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Increasing voltage, from millivolts to 120volts

  1. Feb 5, 2009 #1
    I'm working on a design for a certain kind of generator. My main issue is that based on how the generator works and the circumstances in which I am designing it for, I end up with the problem of having very little voltage but a whole lot of amps. My theoretical/ideal voltage is .065v, and my actual was .032v . So my current rough, home-build design is about 50% of the on paper design. With amps then on paper I've got close to 2,484 amps. So if I get about 50% again then I'd have around 1,242 amps as the total max draw possible.

    Now one way I've been able to increase my volts without altering the amps was to put multiple cathodes and multiple anodes, and running them in series. Then each time my voltage increased. I experimented and did this four times increasing the voltage to .134v. Now I could do this until I got the voltage up to the standard 120 volts, but that would be around 3500-4000 pairs of electrodes. It's not really feasible without increasing the size of my generator which is a possibility but something I'd like to avoid, in terms of making it large enough for 4000 electrodes.

    Right now I'm still very early, and I'd like to just get the voltage up to 120 volts D.C. and power a light bulb. What would be the best way to do that? I'm not sure what to use so I can't design a circuit. I've read about op amps, but I'm not sure if they are the best option. I really don't know what else is used with such low voltage. A friend mentioned to me something about using a charge pump but again I don't know what all the options or best ones might be for such low input voltage.

    Last edited: Feb 5, 2009
  2. jcsd
  3. Feb 6, 2009 #2
    I am interesting in what type of generator we are talking about. Is it really a DC generator? Most generators work exactly like the inverse of an AC motor, which consists of coil windings and a perminent or electromagnet.

    If your generator output voltage is DC, then you need a DC to DC converter which circuits can be found on google.

    If your generator is producing the more traditional AC, then the best thing to use is a transformer.

    You mentioned that you increased the Amps without changing the voltage. How exactly? More info please.
  4. Feb 6, 2009 #3
    I'm working on a Magnetohydrodynamics generator. It's DC because my magnetic field doesn't change and the fluid flows through the magnetic field in one direction, those only causing voltage in one direction. I have some ideas involving multiple magnets and generating an AC current that way but DC is easy and simple. If I could get that to work it would be more beneficial I think.

    I can increase the voltage without changing the amps. Think of my generator like a battery. If you connect 2 AA's in series you get 3 volts, but with the same amount of possible amps. I basically did the same thing. Instead of using just one set of electrodes I used 2 (then 4) and I connected the electrodes in series, so my voltage increased each time. Now since all the electrodes where theoretically the same, my max amperes are the same as both, just now I've got 4x the voltage. The only problem in doing this is that it quickly becomes uneconomical in the terms of the space required for all of the electrodes.
  5. Feb 9, 2009 #4

    I think there is something wrong with this. Total max power output (P=VI=RI^2) of a battery is fixed (primarily due to overheating). Whether the batteries are put in series of parallel doesn't affect max power output. So, in parallel, they give more max current less voltage; and in series they give more voltage less max current (because now the total current flow has to pass through 2 resistances internal to each battery [R=R1+R2] as opposed to the first case where the total current would pass through [R={1/R1 + 1/R2}^-1]). Most batteries are designed for constant voltage rather than constant current (math for constant current generator would be similar), so current not voltage will be the changing variable.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook