Topic: Measurements and Instrumentation
The error in measurement of a dc voltmeter with input signal: 1.5 V, voltage range: 2V, accuracy: $\pm(25$ ppm of reading + 5 ppm of range) is
- A. $\pm 50\text{ }\mu\text{V}$
- B. $\pm 30\text{ }\mu\text{V}$
- C. $\pm 47.5\text{ }\mu\text{V}$
- D. $\pm 10\text{ }\mu\text{V}$
Answer: C. $\pm 47.5\text{ }\mu\text{V}$
Explanation: The error is computed by summing the reading error and the range error components. Error $= \pm [ (1.5 \times 25 \times 10^{-6}) + (2 \times 5 \times 10^{-6}) ] = \pm (37.5 \times 10^{-6} + 10 \times 10^{-6}) = \pm 47.5\text{ }\mu\text{V}$.