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How to measure current induced through loops

  1. Dec 14, 2008 #1
    I'm doing some experiments, and I need to measure the current (and/or voltage) going through several loops of wire as a magnet slides through. The magnet slides parallel under the loops at a certain speed. I have a multimeter and an ammeter. The problem with the ammeter is that it's just a needle and is made for DC current.

    I realized that as the magnet slides toward the center of the loops, the flux increases (positive current), and then as it slides away from the center, the flux decreases (negative current). The current changes so quickly that the needle on the ammeter barely moves, as is expected. With the multimeter, how can I accurately measure the current? I realize it is not steady, but in general, any ideas? I tried measuring the current with the digital multimeter set to AC, but it was varying with currents of between .008-.040 A, which is a big range; and when I make the magnet slide by slower, it tends to be higher, which makes me think that the meter is reading it as I'd like.

    Thank you to anyone who can help me!
  2. jcsd
  3. Dec 14, 2008 #2


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    Well, if you haven't the right measurement apparatus to measure AC, it is somehow difficult to measure. What you could eventually try to do is to put in a rectifier bridge with 4 diodes, but I'm not even sure this will work, as there is a non-neglegible voltage drop over the diodes, and you might not generate enough EMF to overcome this.
  4. Dec 15, 2008 #3
    Well, the digital multimeter can measure AC, but I'm not sure if THIS type of AC is going to be measured correctly by the multimeter. Thanks though.
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