Norman Yarvin wrote:
Right; that's why the whole wire has to be of the thermocouple materials, not just the bit at the end. (Well, perhaps not precisely "has to", but close enough for that to be the standard engineering practice.) It still usually is good enough for the purposes of analysis to regard the junctions as being voltage sources, though.
Well, the proper setup is two identical conductors of "any" conductive material run in parallel finally ending in material A from the selected thermocouple pairing. Both endpoints are bridged by a wire of the B material type. One junction is placed at the point of interest. the other is kept at a controlled or measurable temperature. ( usually a reference block with a PT100/PT1000 resistor added to determine reference temperature ) What you measure is temperature differential between the two A|B junctions. All other potential changes compensate along the wire run. If your (poi) junction is comprised of multiple contacts at different temperatures I see room for improvements. uwe
