Thermocouple meters

The thermocouples provide fast and precise measurements and can be used for example in production, transport, storage, catering, kitchens, supermarkets ...

The thermocouple temperature gauge consists of the connection of two wires of a different metal. At a certain temperature, a potential difference appears between the opposite ends of the two wires (Seebeck effect), whereby the respective variations are linearly related at small intervals.

Therefore, it is possible to determine the temperature when the potential difference and the characteristics of the two metals are known. The measuring end of the thermocouple probe is called the hot junction, while the connection of the thermocouple to the meter is the cold junction.

An error occurs when the cold junction is exposed to room temperature. This error can be prevented by literally placing the cold junction in an ice bath and forcing a reference temperature of 0°C, or by electronically compensating for the temperature effect of the cold junction.

  • fast response
  • direct contact possible
  • wide temperature range
  • long service life

There are different types of thermocouples, determined by an ANSI code that uses a letter of the alphabet. These types consist of different metal alloys of the plus and minus pole and therefore have their specific temperature range. Types E, K, J and T are the most useful, with type K thermocouple being the most commonly used in temperature measurements.

The only difference between these types of thermocouples lies in the measuring range and accuracy. This is mainly due to the difference in metals used to make these different thermocouples. See table below.

Type K thermocouple is used mainly for general temperature measurements in normal environments. Due to its wide temperature range, the Type K thermocouple is the most popular type. At Hanna Instruments, type K has a range of -50.0 to 1350°C. Thermocouple type K has the longest lifetime due to the metals used (Nickel-Chrome/Nickel-Aluminium). These are chemically more inert than the copper or iron used in types J and T.

Choosing a thermocouple depends primarily on the measuring range. The accuracy will also vary. Type T thermocouples should be the most accurate (because of their smaller range). Type J and K have a similar accuracy, but are less accurate than type T.