Thermocouples

A thermocouple is used in electronics, and it consists of a pair of dissimilar metal wires that are joined at one end where a net thermoelectric voltage is generated between the open ends of the wires. This thermoelectric voltage is generated according to the amount of the temperature difference that exists between the two loose ends. This potential difference that is developed in thermocouples is converted into electric potential difference.

Thermocouples are basically cheap and interchangeable with standard connectors, and they can be used to measure a wide range of temperatures. The only limitation in thermocouple wiring is its precision, where system errors that are less than 1 degree Celsius are difficult to achieve.

There are many applications for thermocouples, including thermocouples in differential thermal analysis and as indicators and controllers that do something useful like controlling a heating system. They are used in different measuring applications in medical research, scientific, industrial and food temperature. You have to choose the efficiency of thermocouple according to the required temperature range and sensitivity.

The thermocouple welder can be used for tack welding a hot junction. All that has to be done is to hold the thermocouple wire against the body with the tack welder, and press it down until the power supply is triggered. You will find that the weld can be done within half a second. If you wonder how to weld thermocouples, you will discover that the wires can be welded separately when they are a short distance apart. You just have to adjust the ‘heat’ and ‘time’ on the thermocouple to get either a permanent or removable weld.

There are different thermocouple types in the market, which you have to choose and use as you require. The gas valve thermocouple tends to create an electromagnet in the gas valve, which opens and permits the flow of gas to the main burners. As the thermocouple has to heat before starting the burner, gas appliances come with a startup mode where the knob has to be depressed for thirty seconds after lighting the pilot. After this, there is sufficient electricity generated for the valve to operate correctly.

Thermocouple colors are usually used to indicate the thermocouple type and the polarity of the thermoelectric voltage that is available. The thermocouple recorder loggers are usually preferred in applications needing the monitoring of extremely high temperatures or the monitoring of temperatures over a wide range.

Today, the most commonly used brands of thermocouples are Allison engine thermocouple and Omega thermocouple. There are also different thermocouples used for thermocouple compression fitting. It is up to you to choose the brand and type of thermocouple you need for your appliance.