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Temperature measurement: fundamentals, measurement principles, and sensors
Fundamentals of temperature measurement
Temperature describes the thermal state of a body and is measured via physical effects such as resistance change or thermal radiation. It is not a directly visible quantity, but must be determined technically.
Several factors are decisive for a reliable measurement: the measurement principle, the sensor technology, the design of the probe, as well as ambient conditions and calibration status.
In this fundamentals section, the physical relationships, measurement methods, and influencing factors are systematically explained – as a basis for reproducible and standards-compliant measurement results.
Physical principles
Temperature is a fundamental physical quantity. It describes the thermal state of a system and is based on the kinetic energy of particles. Of decisive importance in practice are the underlying temperature scales, reference points, and normative definitions.
Anyone who wants to measure temperature correctly must understand exactly what is being measured – and under what conditions comparability is achieved.
How is temperature measured? – Setup and resolution
Temperature is measured either by direct contact or via non-contact radiation measurement. Both methods follow different physical principles and place different demands on sensor technology and application.
This page explains the measurement principles systematically and shows when each method is technically appropriate.
Sensors – operating principle and selection
Whether resistance thermometer, thermocouple, or NTC: each sensor principle has specific characteristics in terms of accuracy, temperature range, response time, and long-term stability.
The selection of the right sensor determines the quality of the measurement – not the instrument alone.
Probes – design and response time
In addition to the sensor type, the mechanical design plays a central role. Immersion probes, penetration probes, surface probes, and air probes differ significantly in their design and thermal response time.
This page explains how the design, material, and contact conditions influence the measurement result.
Avoiding measurement errors – how to measure temperature correctly and precisely
Errors usually arise not in the measuring instrument, but in the application. Insufficient contact, incorrect emissivity, thermal influence, or lack of calibration lead to systematic deviations.
Here, typical sources of error are analysed and methodical countermeasures are presented.
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