Calibration & Measurement Confidence#

Trusting the readings. Accuracy, resolution, systematic error, uncertainty. This section comes last because it applies to everything above — every measurement has limits, and knowing those limits is what separates data from guessing.

• Is my instrument accurate enough for this? — Matching instrument specs to measurement needs. When a 3½-digit DMM is fine and when 5½ digits are necessary. When scope sample rate matters and when it doesn’t.
• Could this be a measurement artifact? — Questioning the reading before trusting it. Probe artifacts, aliasing, ground bounce, capacitive coupling from a nearby hand — all the ways a measurement can lie.
• When was this last calibrated / compensated? — Probe compensation, scope self-cal, DMM calibration status. The things worth checking periodically and the things worth checking every session.
• What’s the actual uncertainty? — Understanding measurement uncertainty beyond just “accuracy.” Resolution, repeatability, environmental effects, and knowing how many digits of a reading are real.