a voltmeter has low resistance or high resistance?why?

Asked by Gayatri Narkhede | 30th Jun, 2013, 10:31: AM

Expert Answer:

Voltmeters are put in parallel with the load in order to measure the potential difference between two *different* points. 
If they are in parallel with the load, then at the first junction the current will split and flow into both paths (Kirchhoff's Laws). However, if current is flowing through the voltmeter, then it is not all flowing through the load, and the potential difference across the load would change when the voltmeter is added and removed. This is unfavourable. Therefore, the voltmeter must have a very high resistance so that current doesn't flow through it. (In reality, a little bit of current does still flow through, but it is insignificant in most cases.)

Answered by  | 30th Jun, 2013, 04:28: PM

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