GATE 2023 IN – Question 64
A 1.999 V true-RMS $3\tfrac12$-digit multimeter has accuracy ±0.1% of reading ±2 digits. It measures 100 A RMS line current through a 100:5 Class-1 current transformer with burden $0.1$ Ω ±0.5%. The worst-case absolute error in meter output is ______ V (three decimal places).
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Correct answer: 0.009 to 0.011
Explanation
The nominal secondary current is 5 A and burden voltage 0.5 V. The conventional worst-case first-order percentage sum is $1+0.5+0.1=1.6\%$, giving 0.008 V. On the 1.999 V range, two least-significant digits add 0.002 V. Total error: **0.010 V**; retaining multiplicative cross terms gives the same rounded result.