Question

What is the maximum input voltage that has to be selected to calibrate a dc voltmeter with a full scale voltage range of 1-13v.

(a) ≤ ±14v

(b) ≥ ±13v

(c) ≤ ±15v

(d) = ±14v

I had been asked this question in an international level competition.

This intriguing question comes from Voltage to Current Converter with Floating and Grounded Load topic in portion Operational Amplifier Applications of Linear Integrated Circuits

Answer 1

The correct answer is:

(a) ≤ ±14V

Explanation:

To calibrate a DC voltmeter with a full-scale voltage range of 1–13V, the maximum input voltage needs to be slightly beyond the upper range limit to ensure the voltmeter can accurately measure and display voltages close to the maximum value.

• The calibration process requires accounting for tolerances and ensuring the voltmeter reads correctly over its entire range.
• Choosing a maximum input voltage of ≤ ±14V provides a buffer above the full-scale range of 13V, ensuring the voltmeter is properly calibrated without exceeding safe operational limits.