UNDERSTANDING
THERMOCOUPLES
Every Degree Matters™
Your practical guide to temperature sensing: Thermocouples, RTDs, wire, connectors, and instrumentation.
Our Mission
Thermocouples101.com started as a simple way to demystify thermocouples. Today, it’s a straight-talk guide to both thermocouples and RTD temperature sensors — how they work, when to use each, and how to avoid costly mistakes in the field.
What is a Thermocouple?
A thermocouple is a sensor used to measure temperature. Thermocouples consist of two wire legs made from different metals. The wires legs are welded together at one end, creating a junction. This junction is where the temperature is measured. When the junction experiences a change in temperature, a voltage is created.
The voltage can then be interpreted using thermocouple reference tables to calculate the temperature. This phenomenon is known as the Seebeck Effect.
Wide Range
-200°C to +2300°C (-328°F to +4172°F)
Fast Response
Milliseconds reaction
Durable
Rugged construction
Self-Powered
No external power
How It Works
The Thermocouple Junction
The thermocouple junction produces a tiny voltage where the two different metals join. Heating the junction makes the voltage increase. Cooling makes it decrease. When the thermocouple is connected to a meter, it converts these voltage changes into an accurate temperature reading.
Explore Thermocouple Topics
Navigate through our comprehensive guide to master temperature measurement.
Understand the Seebeck effect, junctions, and the physics behind the sensor.
Read MoreDetailed guide to J, K, T, E, N, R, S, and B type thermocouples and their color codes.
View TypesFrom industrial furnaces to food safety - see where thermocouples are used.
Explore UsesAvoid costly errors like mismatched alloys, reverse polarity, and bad junctions.
Avoid ErrorsWhy we also cover RTDs
Most people start their temperature-sensor journey with thermocouples. They’re rugged, affordable, and everywhere.
But once you care about tight accuracy and long-term stability, you’ll quickly run into RTD temperature sensors.
At Thermocouples101, we walk you through both:
- How thermocouples and RTDs work
- When each makes sense in the real world
- How to wire, install, and troubleshoot them
Quick Decision Guide
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Visit SiteReady to Measure?
TIP TEMPerature Products has over 25 years of experience helping clients find the perfect thermocouple solution.