Omega Speaker Systems TC-08 manual How a thermocouple works

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TC-08 User's Guide

2.2How a thermocouple works

In a closed circuit of two dissimilar metals (a thermocouple), an electric current flows when one of the two junctions is heated with respect to the other. The current continues to flow as long as the two junctions are at different temperatures. The magnitude and direction of the current is a function of the temperature difference between the junctions and of the thermal properties of the metals used in the circuit. This phenomenon is known as the Seebeck Effect.

The conductors can be made of any two dissimilar metals, and when the hot junction is heated the current flow can be observed. If the positions of the hot and cold junctions are reversed, current flows in the opposite direction.

A thermocouple circuit actually generates a measurable, low-voltage output that is almost directly proportional to the temperature difference between the hot junction and the cold junction. A change in this temperature difference produces some net change in the voltage.

Note: More information on choosing and using thermocouples can be found at www.omega.com.