Recent content by mahela007

  1. M

    Voltage limiter for Cockroft/ walton cap charger

    Hello, I'm trying to design a capacitor charging circuit using a Cockroft-walton voltage doubler circuit. My mains voltage is ~220 Volts and the output would be 220*2 = 440. My capacitors are rated for 500V which means that they can be charged safely to about 400V. Is there a circuit...
  2. M

    Force on a ferromagnetic object

    well, I asked this question because I'm building a simple DIY coilgun.. (just 8J of energy stored in the caps). So I'm going to have to resort to trial-and-error. Thanks for your help.
  3. M

    Force Exerted on Ferromagnetic Object by Permanent Magnet

    Thanks for the reply. Yup, the calculations do seem to be complex and even then, if the equations are solved, they only give rough estimates. :( Trial and error it is then..
  4. M

    Force on a ferromagnetic object

    oh well.. Just for the sake of knowledge, does the gradient of the field come into play because all magnets have two poles and because the net force depends on the difference between the force on each end?
  5. M

    Force Exerted on Ferromagnetic Object by Permanent Magnet

    Hello.. I have a very similar problem. Did you make any progress with this? No one on the internet seems to no the answer.. hehe
  6. M

    Force on a ferromagnetic object

    How can one calculate (even as a rough estimate) the force exerted on a ferromagnetic object by a magnetic field created by a solenoid? Thanks
  7. M

    Action of a dielectric in a capacitor

    Sorry.. is there is typo in the 4th line? Are you referring to the electric field as D or the separation of the plates as D?
  8. M

    Action of a dielectric in a capacitor

    Homework Statement A prallel plate capacitor placed in air has a plate area A and a plate separation d. It is cahred to charge Q by connecting a constant foltage source across the plates. The voltage source is then disconnected and a slab of dielectric constant K and thickness h is inserted...
  9. M

    Applying Kirchoff's law to circuit which only has cells

    lol... ok then. Let's say for theoretical purposes that a cell had 0 resistance. Kirchoff's second law says that the algebraic sum of potential differences around a closed loop is 0. The (imaginary) batteries maintain a constant voltage across their terminals. So shouldn't we be able to apply...
  10. M

    Applying Kirchoff's law to circuit which only has cells

    Do we need to consider the current? Don't the cells maintain a potential difference equal to their EMF because they don't have internal resistance?
  11. M

    Applying Kirchoff's law to circuit which only has cells

    Homework Statement Find the Voltage across A B in the following circuit. Each cells has negligible internal resistance and an EMF of E volts. (First diagram in the attached picture) Homework Equations I'm trying to use Kirchoff's second law. The Attempt at a Solution Now, if I...
  12. M

    Why do simple balances always come to rest in a horizontal position ?

    Could you please explain how that works?
  13. M

    Why do simple balances always come to rest in a horizontal position ?

    Why is it that simple balances always come to rest in a horizontal position when equal weights are placed on both ends? If the weights are equal, then (assuming that the distance from each weight to the pivot is the same) the torques produced by the weights are equal and opposite and the net...
  14. M

    Gauss' Law and Infinite plane sheet of charge

    This thread look to be long dead... however, I did find it useful. I had the same question (more or less) as the OP and post #4 did a good job of explaining things. Thanks Doc Al.
  15. M

    Can someone explain the pressure due to an ideal gas in a container?

    I'm having the same problem. I can't understand why the change in momentum has to be divided by the time for taken for one 'lap'...
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