A three-point calibration checks an instrument at 0 percent, 50 percent, and which additional percent?

A three-point calibration checks an instrument at 0 percent, 50 percent, and which additional percent?

• A. 100 percent
• B. 25 percent
• C. 75 percent
• D. 60 percent

Answer: (A)

Three-point calibration uses low, mid, and high reference levels to define how the instrument responds across its full range. By starting at zero, you fix any offset so the output lines up with the true zero. The midpoint tests the slope in the middle of the range, helping to confirm linear behavior. The final reference must be the maximum end of the scale to verify the span and to catch any nonlinearity or gain error that only appears near full-scale. If you skipped testing the top end, you might miss errors that show up at maximum input. So the additional calibration point should be the upper end of the scale, ensuring accurate operation at full scale.

Three-point calibration uses low, mid, and high reference levels to define how the instrument responds across its full range. By starting at zero, you fix any offset so the output lines up with the true zero. The midpoint tests the slope in the middle of the range, helping to confirm linear behavior. The final reference must be the maximum end of the scale to verify the span and to catch any nonlinearity or gain error that only appears near full-scale. If you skipped testing the top end, you might miss errors that show up at maximum input. So the additional calibration point should be the upper end of the scale, ensuring accurate operation at full scale.