A Quick Guide: How to read Thermocouple Reference Table (Type K, E, J, T, N)

How to Use Thermocouple Reference Table

Let’s take type K thermocouple temperature vs. voltage table as an example. A type k thermocouple is a common tool used for measuring temperature. It works by measuring the thermoelectric voltage, which varies with temperature. This table lists the thermoelectric voltage values of k type thermocouple for different temperatures. The millivolt outputs for each thermocouple type across the entire temperature ranges are determined by NIST and presented in this table.

Before getting directly into the table, it would be helpful to know some simple steps to fully understand how to read the table.

3 Steps to Use the Table

1. Determine the Temperature: Find the temperature you need to measure. For example, let's say the temperature is -50°C.
2. Locate the Corresponding Voltage: Find -50°C on the left side of the table, then look across the top to find the reference junction temperature. For instance, if the reference junction temperature is -5°C, find the column for -5°C.
3. Read the Voltage Value: Read the thermoelectric voltage value where the row and column intersect. In this example, the voltage value for -50°C with a -5°C reference junction is -2.067 millivolts.

Example:

Suppose you need to measure the temperature of an object, and the reference junction temperature is -5°C. If you read a voltage of -2.067 millivolts, you can find that the object's temperature is -50°C using the table.

Thermoelectric Voltage in Millivolts

3 Important Tips to Keep in Mind When Using a Table

• Calibration and Accuracy: make sure the thermocouple and the measuring device are properly calibrated to ensure accurate readings.
• Reference Junction Temperature: verify that the reference junction temperature is correctly set, as it affects the measurement results.
• This table is very helpful for accurately measuring temperature. Just match the voltage reading with the reference junction temperature to find the actual temperature of the object.

In the following tables, we will show temperature and voltage reference tables of several common thermocouple types (from Table 1 to 5) at certain temperature interval as an example. The reference junction temperature is 0°C.

Table 1: Type K thermocouples - Thermoelectric Voltage in Millivolts

Table 2: Type E thermocouples - Thermoelectric Voltage in Millivolts

Table 3: Type J thermocouples - Thermoelectric Voltage in Millivolts

Table 4: Type T thermocouples - Thermoelectric Voltage in Millivolts

Table 5: Type N thermocouples - Thermoelectric Voltage in Millivolts

Want more information about the complete reference table?