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How is a galvanometer converted into a voltmeter? |
Answer» Solution :A galvanometer can be converted into a voltmeter by CONNECTING a high resistance in series with it.  In figure, p.d. across AB is `V=(R+G)I_g` `R=V/I_g-G` To convert a galvanometer into a voltmeter , a high resistance is connected in series with the coil. The galvanometer with this modification is called a voltmeter. The value of the high resistance R to be connected in series with the coil depends on the maximum potential difference to be measured . If `I_g` be the current for a FULL SCALE DEFLECTION then, `V=I_g(G+R)` G is the resistance of the galvanometer.  `therefore R=V/I_g-G` Since G and R are constants , the scale can be graduated to read potential differences directly. A voltmeter is used for measurement of potential difference . It should be connected in parallel in a circuit. |
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