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Homework Help: Triple-Scale Voltmeters.

  1. Feb 22, 2005 #1
    Drawing a circuit

    I have to "devise and draw a circuit for building a triple-scale voltmeter where the scale is changed by connecting to different terminals".

    We did construct a "voltmeter" in lab by connecting a battery eliminator, galvanometer, and resistor. We knew the volts going through it, as well as the ohms, cause we had to set each one. We actually set the resistance to max out the galvanometer, and had the volts set to a constant. We calculated the max current the galvanometer could record, and the reisistance of the galvanometer.

    I understood that part, is the question asking us to do the same thing?? :confused: I don't want someone to construct it for me, just to help explain what the question is asking
    Last edited: Feb 22, 2005
  2. jcsd
  3. Feb 23, 2005 #2
    Lets see. YOu want to construct a triple-scale voltmeter. You said scale is changed by connecting to different terminals.

    A triple-scale voltmeter is able to measure voltages at three voltage ranges. If this is the case,

    you have to do the same thing for the rest of the scales. Only difference is you will use a different voltage (battery) now and for each case find the series resistnace that will maxmize the gal meter current.

    Once you determined the resistors that max the galvanometer current for each voltage range, (say R1 , R2 and R3) u can add these resistors to your circuit in parallel to each other and add some kind of a switch at the junction to switch between resistors (or voltage ranges).
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