Which combination of thermocouple types is commonly used for temperature sensing?

• A. A, B, C type
• B. L, M, N type
• C. S, R, B type
• D. J, K, T type

Answer: (D)

Thermocouples come in several metal pairings, and the choice depends on temperature range, environment, and cost. For everyday temperature sensing, the combination of J, K, and T types is the most common. J (iron-constantan) is solid for moderate temperatures, K (chromel-alumel) covers a broad range and is widely used because it’s cheap and robust, and T (copper-constantan) excels at lower temperatures with good accuracy and fast response.

These three types are widely supported by instrumentation and data acquisition hardware, with readily available connectors and reference data, which makes them the go-to choice in many labs and industrial settings. The other groups are more specialized: S, R, and B are noble-metal types used at very high temperatures but at a higher cost and with different behavior that isn’t as broadly suitable for general sensing. L and M are less common, and N is similar to K but isn’t as universally deployed as K. So the best-supported, most commonly used trio is J, K, and T.