A Type K thermocouple is one of the most common and widely used thermocouples in temperature measurement. It consists of two different metals: Nickel-Chromium (NiCr) for the positive leg (also called the “hot” leg) and Nickel-Aluminum (NiAl) for the negative leg (also called the “cold” leg). When the junction of these two metals is exposed to a temperature gradient, it generates a voltage (Seebeck effect) that can be correlated to temperature.

Key Characteristics of Type K Thermocouple

1. Temperature Range

• General Range: Typically -200°C to +1372°C (-328°F to +2502°F).
• This wide range makes Type K thermocouples versatile for many applications, including both low and high-temperature measurements.

2. Accuracy

• The accuracy of a Type K thermocouple is generally ±2.2°C or 0.75% of the temperature reading (whichever is greater). While not as precise as RTDs or thermistors, Type K thermocouples are good for many industrial and scientific applications.
• Accuracy can vary depending on the temperature range and quality of the thermocouple.

3. Materials and Construction

• Positive Leg (Chromel): A nickel-chromium alloy.
• Negative Leg (Alumel): A nickel-aluminum alloy.
• The two wires are usually insulated with materials like ceramic or fiberglass, especially at higher temperatures.