Learning path · 11 articles · about 22 min
Temperature calibration in practice
Bench-level technique for PRTs, thermocouples and loggers: sources, immersion, self-heating, hysteresis, references and the ice point.
For: Laboratory technicians and engineers performing or specifying temperature calibrations.
- 01CalibrationHow to calibrate a Pt100Calibration by comparison against a reference thermometer, and the factors that decide the uncertainty.2 min
- 02CalibrationChoosing calibration pointsCalibrate where you measure. Points should bracket the use range and include any temperature where a decision is made.2 min
- 03CalibrationLiquid bath versus dry-block calibratorA stirred liquid bath offers the best uniformity; a dry block offers speed, portability and no fluid — the choice is about uncertainty and practicality.2 min
- 04CalibrationImmersion depth and stem conductionA probe conducts heat along its stem. Insufficient immersion makes the sensor read closer to room temperature than to the medium.2 min
- 05CalibrationSelf-heating in resistance thermometersThe measuring current warms the sensing element. The effect depends on the medium — so calibrate at a current and condition representative of use.2 min
- 06CalibrationHysteresis in temperature sensorsA sensor can read differently at the same temperature depending on where it came from. Calibrations that only approach from one direction hide it.2 min
- 07CalibrationSelecting a reference thermometerThe reference sets the floor of your uncertainty. Choose it for stability and a calibration uncertainty comfortably below what you need to deliver.2 min
- 08CalibrationThe ice-point checkA properly made ice bath gives 0 °C to within a few millikelvin — a cheap, repeatable way to watch a PRT for drift between calibrations.2 min
- 09UncertaintyThe reference thermometer's contribution to uncertaintyThe reference contributes its certificate uncertainty, its drift since calibration, and any interpolation or self-heating effects. Together they set the floor of what can be claimed.2 min
- 10CalibrationHow temperature data loggers are calibratedLoggers are calibrated as a system — sensor, electronics and firmware — usually in a chamber, at the points that matter for their use.2 min
- 11CalibrationHow thermocouples are calibratedThermocouples measure with the whole wire, not just the tip — which is why immersion, homogeneity and the reference junction dominate their calibration.2 min
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