The primary difference between Type J and Type K thermocouples is the measuring range, and the sensitivity. Type K is the most common general-purpose thermocouple with a sensitivity of approximately 41 µV/°C. A wide variety of probes are available in its −50°C to +900°C / -58°F to +1652°F range. Type K wire color standard is yellow (+) and red (-). Type J has a more restricted range of −50 to +400°C, but higher sensitivity of about 50 µV/°C. Type J wire color standard is white (+) and red (-).
Specifications
Ambient
Type
Application
Temperature Range
Accuracy
K
Beaded wire for fast response in air and gas in difficult to access areas
-50 to 300ºC -58 to 572ºF Max. short-term operating temperature: 250°C (482°F)
± 0.4%
It is an ultra fast response naked-bead thermocouple suitable for many general purpose applications.