Thermal EMF Error in Current Sense Resistors

Whenever the junction of two dissimilar metals is heated, there is a voltage generated across the junction, the magnitude and polarity of which depends upon the specific metals and the amount of heat applied and is expressed in microvolts per degree centigrade.This phenomenon is known as the Seebeck or thermocouple effect and occurs in resistors at the resistor element/ termination junction. It appears as a battery in the circuit and is a significant source of error in low level DC measurements. This demonstration measures and compares the Thermal EMF error, in both magnitude and decay time, of four different resistor technologies.

6/8/2012 5:57:48 PM