Calibration drift is best described as which of the following?

• A. A sudden jump in output after recalibration
• B. A gradual change in sensor output or calibration constants with time
• C. A random noise on the signal
• D. A change caused by external electrical interference

Answer: (B)

Calibration drift is a gradual, time-related change in the sensor’s response, so the output slowly moves away from its previously calibrated value. This happens as sensing elements age and are affected by environmental factors, causing small, persistent shifts in gain or offset over time. Because the change evolves slowly, the reading drifts and needs periodic recalibration to restore accuracy. It’s not a sudden jump (that would imply a fault), not just random noise (which fluctuates without a trend), and not primarily caused by external interference (which tends to produce spikes or noise rather than a steady trend).