A digital ammeter on its range resolves (one "digit" )

PHYSICS · Multi-part · Fermi University Physics · Scientific Practice & Experimental Methods · Quantities, units and the practice of measurement · Uncertainty in measurement

Measurement and Method, Ch The instrument: resolution, sensitivity, calibration and traceability

Problem

A digital ammeter on its

2.000\,\mathrm{A}

range resolves

1\,\mathrm{mA}

(one "digit"

=0.001\,\mathrm{A}

). Its specification is

\pm(1.2\%\ \mathrm{of\ reading} + 4\ \mathrm{digits})

. Find the uncertainty interval, in amperes and as a percentage of the reading, for each of the following readings on this range: ((a))

1.850\,\mathrm{A}

((b))

0.620\,\mathrm{A}

((c))

0.055\,\mathrm{A}

((d)) The ammeter's

200.0\,\mathrm{mA}

range resolves

0.1\,\mathrm{mA}

, with the same specification. Find the interval for the

0.055\,\mathrm{A}

current read on that range instead, and say which range it should be read on.

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