Thermocouple is one of the most popular type of temperature sensors used in industry. Thermocouple uses thermoelectric effect
The construction of thermocouple sensors
Thermocouple is produced as two wires: metal (alloy) X and metal (alloy) Y join (welded) at one end. Such pair of wires is then coiled with an electrical insulator and tightly coated in metal jacket welded on the end. The end product looks like a metal wire with one end smooth, and at the other end with two thin wires X and Y led out.
Advantages of thermocouple sensors
• Simple construction.
• Good signal repeatability between different units.
• Small dimensions, and in consequence small inertia and heat capacity.
• Wide range of temperature measurement.
• Reliability and durability.
• Thermocouple generate an active signal (voltage) that allows to work without power supply; and with small
impedance, that gives better resistance to electromagnetic noise.
• Low production cost in case of popular thermocouples.