What is the response time of a thermocouple?
The response time of a thermocouple is governed by the type of thermocouple junction, the diameter of the sensor and the environmental conditions of a particular application. In general a smaller diameter thermoocouple will have a faster response time than a larger diameter of the same construction, but the maximum temperature will be lower. An exposed junction will have the fastest response but will be limited in application use.
The table below shows typical response times for mineral insulated thermocouples assemblies with insulated junctions being plunged into boiling water from air at 20°C. The figures refer to the times taken for the thermocouple junctions to achieve 63.2% of this instantaneous step change. For assemblies with grounded junctions the response times are approximately 50% of those listed.
Typical Response Times for Mineral Insulated Thermocouples