Answer to Question #65002 in Electric Circuits for megha

Question

what is meant by range of an ammeter? also of voltmeter and galvanometer?

Answer 1

Range of ammeter(voltmeter) is maximum current(voltage) that this ammeter(voltmeter) can measure. The range corresponds to full-scale voltage or current. The advantage of using ranges is greater accuracy.
For example, suppose you measure 0.8V on a 1V range and on a 100V range.
For an analog meter, you estimate the reading by eye against a scale, while for a digital meter there is an analog to digital converter with a certain number of bits resolution.
Suppose 10 bits corresponds to full scale - 1 bit is about 0.1V on a 100V scale and 0.001V on a 1V scale. So on the 1V scale you have 0.8V +/- 0.001V or about 0.1% accuracy, and on the 100V scale you have 0.8V +/- 0.1V or about 10% accuracy.
A similar problem exists on the analog meter - you just can't read it that well.