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Variation on the Van Der Pauw method

  1. Sep 17, 2015 #1
    First time on this forum, hoping you can help clear something up for me.

    I am using the Van der Pauw method to characterize the sheet resistance of a metal film. In the standard setup, current is pushed through two contacts and voltage is measured across the other two contacts. My colleagues are insisting that reversing this setup, pushing a voltage and measuring a current, will produce the same results. But they haven't been able to explain why. Wouldn't this create a current divider? The measured current wouldn't be the same as the current crossing the square.

    I haven't been able to find any sources supporting this and they haven't been able to give me any. I'm also worried that since my films have a very low 2 pt probe resistance, the low impedance of the ammeter would add an error to the measurement.

    Any help clearing this up would be appreciated.
  2. jcsd
  3. Sep 18, 2015 #2


    Staff: Mentor

    Try https://en.wikipedia.org/wiki/Linear_motor

    Specific questions such as "how strong should the magnet be" can not be answered unless you specify the requirements of the motor. How much liner force? How much power?

    If you want only approxiate numbers, borrow them from ordinary electric motors. A linear motor is nothing more than a rotating motor flattened out. The basic electric and magnetic quantities don't change much by flattening.
  4. Sep 18, 2015 #3

    The Electrician

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    Gold Member

    Last edited: Sep 18, 2015
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