产品选型指南

A J-type thermocouple uses iron and a copper-nickel alloy to generate a thermoelectric voltage in response to a temperature difference. It provides relatively high thermoelectric output and performs well across low-to-medium and medium temperature ranges. This article explains its construction, operating principle, temperature range, accuracy, limitations, applications, and key selection considerations.

K-type thermocouples are among the most widely used thermocouple sensors in industrial, HVAC, maintenance, and laboratory applications. They generate a thermoelectric voltage through the Seebeck effect and offer a broad temperature range, fast response, simple construction, and good overall versatility.

A thermocouple does not measure the average temperature along the entire probe. Its temperature signal is generated at the measuring junction where the two dissimilar thermocouple conductors are joined. In most probes, this junction is located near the probe tip, although its exact position depends on whether the junction is exposed, grounded, or ungrounded. Understanding the true sensing location is essential for correct probe placement and reliable temperature measurement.

A thermocouple accuracy class describes the permissible deviation of the thermocouple itself from the standardized temperature–EMF relationship. The allowable tolerance depends on thermocouple type, temperature range and the applicable standard. Understanding Class 1, Class 2 and Class 3 helps users select the correct probe and assess the achievable accuracy of the complete temperature measurement system.

A thermocouple thermometer may support a very wide measurement range, but the actual temperatures it can measure safely also depend on the thermocouple probe type, sheath, insulation, construction, and connecting components. This article explains the difference between thermometer measurement range and probe temperature range, and how to determine the actual usable range of a complete thermocouple measurement system.

A thermocouple can cover a wide temperature range, but its actual usable range is not determined by thermocouple type alone. Probe construction, sheath and insulation materials, connectors, and the thermometer input range can all impose additional limits. Understanding these factors helps ensure the correct thermocouple probe and thermometer are selected for a given application.

K-, J-, T-, and E-type thermocouples are widely used base-metal thermocouples. Because each type uses a different combination of conductor materials, they differ in temperature range, thermoelectric output, environmental suitability, and typical applications. This article compares their key characteristics and explains how to select the appropriate thermocouple for a specific measurement task.

A thermocouple generates a voltage based on the temperature difference between its measuring junction and reference junction rather than the measuring junction temperature alone. Cold junction compensation (CJC) measures the temperature near the thermocouple input terminals and applies the required correction so the instrument can determine the actual measuring-junction temperature. This article explains how CJC works, how it is implemented, and what can cause compensation errors.

A thermocouple does not measure the absolute temperature of its measuring junction directly. Instead, it generates a thermoelectric voltage related to the temperature difference between the measuring junction and the reference junction. This article explains the functions of the hot and cold junctions, why the cold junction is not necessarily “cold,” and how cold-junction compensation affects practical temperature measurements.

A thermocouple measurement system normally consists of a thermometer and a thermocouple probe, so the accuracy specified for the instrument alone does not represent the accuracy of the complete measurement system. This article explains the differences between thermometer accuracy, probe accuracy, and overall system accuracy, as well as the main sources of error in practical thermocouple measurements.

A thermocouple generates a thermoelectric voltage determined by the temperatures of both the measuring junction and the reference junction. A thermocouple thermometer therefore cannot determine the measuring-junction temperature from voltage alone. Cold junction compensation measures the temperature near the instrument terminals and mathematically corrects for the reference-junction temperature so that the actual measurement temperature can be calculated accurately.

A thermocouple thermometer is a contact temperature measuring instrument that converts a temperature difference into a small thermoelectric voltage. The instrument measures this voltage, determines the reference-junction temperature, applies cold junction compensation, and uses the appropriate thermocouple reference function to calculate the actual measurement temperature.