MALVERN, PENNSYLVANIA - Jan. 18, 2012 - Vishay Precision Group, Inc. (NYSE: VPG) today announced that its Vishay Foil Resistors division (VFR) has released a new video that  demonstrates the thermal EMF characteristics of four resistor technologies: thin film, thick film, metal strip, and Bulk Metal® Foil. The short video demonstrates how a slight temperature rise can introduce significant thermal EMF error voltages in the thin film, thick film, and metal strip resistors, but causes practically zero thermal EMF error in the Bulk Metal Foil resistor.
Electronic components, and resistors in particular, incorporate dissimilar metals in their construction. When one of the two junctions of dissimilar metals is heated, a voltage is generated between the two junctions. This is known as the Seebeck or thermocouple effect, and it occurs in resistors at the resistor's two element/termination junctions. When heat is applied to  either junction, the error voltage increase is directly proportional to the temperature increase. This is called thermal EMF, and it can be a very big problem in applications where it is necessary to make accurate, low-level circuit measurements.
Using a test that measures and compares the thermal EMF error of a resistor, in both magnitude and decay time, the demo video introduced today highlights the inherent low thermal EMF characteristics of VPG Bulk Metal® Foil resistors. The test system used in this demonstration consists of a precision voltmeter, laptop, thermal EMF test fixture, and 50 m
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© Publicnow - 2012