The development of contact temperature sensors ended in principle towards the end of 19th century. Already at the start of the 18th century there existed efforts to establish uniform criteria – scales – for the measurement of temperature. Even today, in the 21st century, these efforts still continue – even though today the discussion is about milli- and micro-Kelvin.
The mere development of temperature sensors lasted for about 250 years. In the approximately 110 years thereafter until today temperature became the most frequently measured unit. The thermocouples play a decisive role here – they have a share of approximately 60% of the production and application numbers. The functional principle of temperature sensors has basically not changed since the beginnings in the 17th century. The apparent disadvantage that the electric measuring value of thermocouples is in the range of a few millivolts has been more than compensated by the instrument technology available today.
The possibility to adapt especially thermocouples almost without problems to practically any industrial measurement task makes them a nearly ideal sensor.
More information you`ll find in our document Thermocouples for industrial applications.