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