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Homework Help: Volmeters in circuits

  1. Feb 23, 2009 #1
    For voltmeters with a finite resistance placed in a circuit, What can be done to get a correect reading of potential difference? my teacher said you would have to place a resistor between the leads of the voltmeter to get a close to correct reading, but im just not quite wrapping my head around this idea.
  2. jcsd
  3. Feb 23, 2009 #2


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    It doesn't make sense to put a resistor across the meter (unless you mean a resistor already in the circuit).

    There isn't much you can do other than to learn the resistance of the meter (often stated on the face of the meter) and do some calculations to see how it is affecting the circuit.

    At one time this was a serious problem because Voltmeters had something like 20K ohms resistance per volt on the range used. However, electronic Voltmeters usually have much higher resistance due to a field affect transistor on the front end. If you have a modern meter it is unlikely that its resistance is affecting a circuit significantly.
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