Ungrounded vs. grounded thermocouples
This article will explain the difference between ungrounded and grounded thermocouples.
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Thermocouples are also known as "probes".
Thermocouples are made of two different metals in the form of wires that are welded together to form a junction. The junction is protected by a metal hull.
It is not possible to determine whether the thermocouple is grounded or ungrounded just by looking at it.
You will need a multimeter to perform this test, as shown in this video by Omega.
Source: https://www.omega.com/en-us/resources/selecting-a-thermocouple
Ungrounded thermocouples
When a thermocouple is ungrounded, the junction is detached from the sensor hull and electrically isolated.
The detached junction results in slower response times compared to grounded probes. The electrically isolated junction prevents the signal from being interrupted by electrical noise. The accuracy of the temperature measurement is much higher.
At Cropster, we recommend ungrounded probes to measure your temperatures.
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Grounded thermocouples
When a thermocouple is grounded, the junction is welded directly to the inside of the hull at the tip of the sensor, which results in an effective heat transfer, thus faster response times.
However, grounded thermocouples are prone to inducing noise from ground loops, which results in a less accurate reading.
These types of probes are recommended to measure the temperature of gases and liquids.
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Congratulations! You have learned what the difference is between the ungrounded and grounded thermocouples.
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